1
|
Malinowski R, Singh D, Kasprzewska A, Blicharz S, Basińska-Barczak A. Vascular tissue - boon or bane? How pathogens usurp long-distance transport in plants and the defence mechanisms deployed to counteract them. THE NEW PHYTOLOGIST 2024. [PMID: 39101283 DOI: 10.1111/nph.20030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2024] [Accepted: 06/13/2024] [Indexed: 08/06/2024]
Abstract
Evolutionary emergence of specialised vascular tissues has enabled plants to coordinate their growth and adjust to unfavourable external conditions. Whilst holding a pivotal role in long-distance transport, both xylem and phloem can be encroached on by various biotic factors for systemic invasion and hijacking of nutrients. Therefore, a complete understanding of the strategies deployed by plants against such pathogens to restrict their entry and establishment within plant tissues, is of key importance for the future development of disease-tolerant crops. In this review, we aim to describe how microorganisms exploit the plant vascular system as a route for gaining access and control of different host tissues and metabolic pathways. Highlighting several biological examples, we detail the wide range of host responses triggered to prevent or hinder vascular colonisation and effectively minimise damage upon biotic invasions.
Collapse
Affiliation(s)
- Robert Malinowski
- Department of Integrative Plant Biology, Institute of Plant Genetics of the Polish Academy of Sciences, ul. Strzeszynska 34, Poznań, 60-479, Poland
| | - Deeksha Singh
- Department of Integrative Plant Biology, Institute of Plant Genetics of the Polish Academy of Sciences, ul. Strzeszynska 34, Poznań, 60-479, Poland
| | - Anna Kasprzewska
- Regulation of Gene Expression Team, Institute of Plant Genetics of the Polish Academy of Sciences, ul. Strzeszynska 34, Poznań, 60-479, Poland
| | - Sara Blicharz
- Department of Integrative Plant Biology, Institute of Plant Genetics of the Polish Academy of Sciences, ul. Strzeszynska 34, Poznań, 60-479, Poland
| | - Aneta Basińska-Barczak
- Department of Integrative Plant Biology, Institute of Plant Genetics of the Polish Academy of Sciences, ul. Strzeszynska 34, Poznań, 60-479, Poland
| |
Collapse
|
2
|
Roychowdhury R, Mishra S, Anand G, Dalal D, Gupta R, Kumar A, Gupta R. Decoding the molecular mechanism underlying salicylic acid (SA)-mediated plant immunity: an integrated overview from its biosynthesis to the mode of action. PHYSIOLOGIA PLANTARUM 2024; 176:e14399. [PMID: 38894599 DOI: 10.1111/ppl.14399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2024] [Revised: 05/05/2024] [Accepted: 05/16/2024] [Indexed: 06/21/2024]
Abstract
Salicylic acid (SA) is an important phytohormone, well-known for its regulatory role in shaping plant immune responses. In recent years, significant progress has been made in unravelling the molecular mechanisms underlying SA biosynthesis, perception, and downstream signalling cascades. Through the concerted efforts employing genetic, biochemical, and omics approaches, our understanding of SA-mediated defence responses has undergone remarkable expansion. In general, following SA biosynthesis through Avr effectors of the pathogens, newly synthesized SA undergoes various biochemical changes to achieve its active/inactive forms (e.g. methyl salicylate). The activated SA subsequently triggers signalling pathways associated with the perception of pathogen-derived signals, expression of defence genes, and induction of systemic acquired resistance (SAR) to tailor the intricate regulatory networks that coordinate plant immune responses. Nonetheless, the mechanistic understanding of SA-mediated plant immune regulation is currently limited because of its crosstalk with other signalling networks, which makes understanding this hormone signalling more challenging. This comprehensive review aims to provide an integrated overview of SA-mediated plant immunity, deriving current knowledge from diverse research outcomes. Through the integration of case studies, experimental evidence, and emerging trends, this review offers insights into the regulatory mechanisms governing SA-mediated immunity and signalling. Additionally, this review discusses the potential applications of SA-mediated defence strategies in crop improvement, disease management, and sustainable agricultural practices.
Collapse
Affiliation(s)
- Rajib Roychowdhury
- Department of Plant Pathology and Weed Research, Institute of Plant Protection, Agricultural Research Organization (ARO) - Volcani Institute, Rishon Lezion, Israel
| | - Sapna Mishra
- Department of Plant Pathology and Weed Research, Institute of Plant Protection, Agricultural Research Organization (ARO) - Volcani Institute, Rishon Lezion, Israel
| | - Gautam Anand
- Department of Plant Pathology and Weed Research, Institute of Plant Protection, Agricultural Research Organization (ARO) - Volcani Institute, Rishon Lezion, Israel
| | - Debalika Dalal
- Department of Botany, Visva-Bharati Central University, Santiniketan, West Bengal, India
| | - Rupali Gupta
- Department of Plant Pathology and Weed Research, Institute of Plant Protection, Agricultural Research Organization (ARO) - Volcani Institute, Rishon Lezion, Israel
| | - Ajay Kumar
- Amity Institute of Biotechnology, Amity University, Noida, Uttar Pradesh, India
| | - Ravi Gupta
- College of General Education, Kookmin University, Seoul, South Korea
| |
Collapse
|
3
|
Király L, Zechmann B, Albert R, Bacsó R, Schwarczinger I, Kolozsváriné Nagy J, Gullner G, Hafez YM, Künstler A. Enhanced Resistance to Viruses in Nicotiana edwardsonii 'Columbia' Is Dependent on Salicylic Acid, Correlates with High Glutathione Levels, and Extends to Plant-Pathogenic Bacteria and Abiotic Stress. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2024; 37:36-50. [PMID: 37750816 DOI: 10.1094/mpmi-07-23-0106-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/27/2023]
Abstract
Our earlier research showed that an interspecific tobacco hybrid (Nicotiana edwardsonii 'Columbia' [NEC]) displays elevated levels of salicylic acid (SA) and enhanced resistance to localized necrotic symptoms (hypersensitive response [HR]) caused by tobacco mosaic virus (TMV) and tobacco necrosis virus (TNV), as compared with another interspecific hybrid (Nicotiana edwardsonii [NE]) derived from the same parents. In the present study, we investigated whether symptomatic resistance in NEC is indeed associated with the inhibition of TMV and TNV and whether SA plays a role in this process. We demonstrated that enhanced viral resistance in NEC is manifested as both milder local necrotic (HR) symptoms and reduced levels of TMV and TNV. The presence of an adequate amount of SA contributes to the enhanced defense response of NEC to TMV and TNV, as the absence of SA resulted in seriously impaired viral resistance. Elevated levels of subcellular tripeptide glutathione (GSH) in NEC plants in response to viral infection suggest that in addition to SA, GSH may also contribute to the elevated viral resistance of NEC. Furthermore, we found that NEC displays an enhanced resistance not only to viral pathogens but also to bacterial infections and abiotic oxidative stress induced by paraquat treatments. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
Collapse
Affiliation(s)
- Lóránt Király
- Department of Plant Pathophysiology, Plant Protection Institute, Centre for Agricultural Research, ELKH, H-1022, Budapest, Hungary
| | - Bernd Zechmann
- Center for Microscopy and Imaging, Baylor University, One Bear Place, no. 97046, Waco, TX 76798, U.S.A
| | - Réka Albert
- Institute of Plant Sciences and Environmental Protection, Faculty of Agriculture, University of Szeged, H-6800, Hódmezővásárhely, Hungary
| | - Renáta Bacsó
- Department of Plant Pathophysiology, Plant Protection Institute, Centre for Agricultural Research, ELKH, H-1022, Budapest, Hungary
| | - Ildikó Schwarczinger
- Department of Plant Pathophysiology, Plant Protection Institute, Centre for Agricultural Research, ELKH, H-1022, Budapest, Hungary
| | - Judit Kolozsváriné Nagy
- Department of Plant Pathophysiology, Plant Protection Institute, Centre for Agricultural Research, ELKH, H-1022, Budapest, Hungary
| | - Gábor Gullner
- Department of Plant Pathophysiology, Plant Protection Institute, Centre for Agricultural Research, ELKH, H-1022, Budapest, Hungary
| | - Yaser Mohamed Hafez
- EPCRS Excellence Center & Plant Pathology and Biotechnology Lab, Department of Agricultural Botany, Faculty of Agriculture, Kafrelsheikh University, 33516 Kafr-El-Sheikh, Egypt
| | - András Künstler
- Department of Plant Pathophysiology, Plant Protection Institute, Centre for Agricultural Research, ELKH, H-1022, Budapest, Hungary
| |
Collapse
|
4
|
He S, Huang K, Li B, Lu G, Wang A. Functional Analysis of a Salicylate Hydroxylase in Sclerotinia sclerotiorum. J Fungi (Basel) 2023; 9:1169. [PMID: 38132770 PMCID: PMC10744347 DOI: 10.3390/jof9121169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2023] [Revised: 11/27/2023] [Accepted: 11/30/2023] [Indexed: 12/23/2023] Open
Abstract
Salicylic acid plays a crucial role during plant defense to Sclerotinia sclerotiorum. Some bacteria and a few fungi can produce salicylate hydroxylase to degrade SA to suppress plant defense and increase their virulence. But there has been no single salicylate hydroxylase in Sclerotinia sclerotiorum identified until now. In this study, we found that SS1G_02963 (SsShy1), among several predicted salicylate hydroxylases in S. sclerotiorum, was induced approximately 17.6-fold during infection, suggesting its potential role in virulence. SsShy1 could catalyze the conversion of SA to catechol when heterologous expression in E. coli. Moreover, overexpression of SsShy1 in Arabidopsis thaliana decreased the SA concentration and the resistance to S. sclerotiorum, confirming that SsShy1 is a salicylate hydroxylase. Deletion mutants of SsShy1 (∆Ssshy1) showed slower growth, less sclerotia production, more sensitivity to exogenous SA, and lower virulence to Brassica napus. The complemented strain with a functional SsShy1 gene recovered the wild-type phenotype. These results indicate that SsShy1 plays an important role in growth and sclerotia production of S. sclerotiorum, as well as the ability to metabolize SA affects the virulence of S. sclerotiorum.
Collapse
Affiliation(s)
- Shengfei He
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (S.H.); (K.H.); (B.L.); (G.L.)
- Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Kun Huang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (S.H.); (K.H.); (B.L.); (G.L.)
- Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Baoge Li
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (S.H.); (K.H.); (B.L.); (G.L.)
- Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Guodong Lu
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (S.H.); (K.H.); (B.L.); (G.L.)
| | - Airong Wang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (S.H.); (K.H.); (B.L.); (G.L.)
- Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| |
Collapse
|
5
|
Cheng B, Xu L, Bilal MS, Huang Q, Niu D, Ma H, Zhou S, Peng A, Wei G, Chen F, Zeng L, Lin H, Baig A, Wang X, Zou X, Zhao H. Small RNAs contribute to citrus Huanglongbing tolerance by manipulating methyl salicylate signaling and exogenous methyl salicylate primes citrus groves from emerging infection. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2023; 116:1309-1324. [PMID: 37614043 DOI: 10.1111/tpj.16426] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 07/14/2023] [Accepted: 08/01/2023] [Indexed: 08/25/2023]
Abstract
Citrus production is severely threatened by the devastating Huanglongbing (HLB) disease globally. By studying and analyzing the defensive behaviors of an HLB-tolerant citrus cultivar 'Shatangju', we discovered that citrus can sense Candidatus Liberibacter asiaticus (CLas) infection and induce immune responses against HLB, which can be further strengthened by both endogenously produced and exogenously applied methyl salicylate (MeSA). This immune circuit is turned on by an miR2977-SAMT (encoding a citrus Salicylate [SA] O-methyltransferase) cascade, by which CLas infection leads to more in planta MeSA production and aerial emission. We provided both transgenic and multi-year trail evidences that MeSA is an effective community immune signal. Ambient MeSA accumulation and foliage application can effectively induce defense gene expression and significantly boost citrus performance. We also found that miRNAs are battle fields between citrus and CLas, and about 30% of the differential gene expression upon CLas infection are regulated by miRNAs. Furthermore, CLas hijacks host key processes by manipulating key citrus miRNAs, and citrus employs miRNAs that coordinately regulate defense-related genes. Based on our results, we proposed that miRNAs and associated components are key targets for engineering or breeding resistant citrus varieties. We anticipate that MeSA-based management, either induced expression or external application, would be a promising tool for HLB control.
Collapse
Affiliation(s)
- Baoping Cheng
- Plant Protection Research Institute, Guangdong Academy of Agricultural Sciences/Guangdong Provincial Key Laboratory of High Technology for Plant Protection, Guangzhou, 510640, China
- Key Laboratory of Green Prevention and Control on Fruits and Vegetables in South China, Ministry of Agriculture and Rural Affairs, Guangzhou, Guangdong, 510642, China
| | - Le Xu
- College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, 210095, China
| | - Muhammad Saqib Bilal
- College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, 210095, China
| | - Qing Huang
- College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, 210095, China
| | - Dongdong Niu
- College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, 210095, China
| | - Hongyu Ma
- College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, 210095, China
| | - Shaoxia Zhou
- College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, 210095, China
| | - Aitian Peng
- Plant Protection Research Institute, Guangdong Academy of Agricultural Sciences/Guangdong Provincial Key Laboratory of High Technology for Plant Protection, Guangzhou, 510640, China
- Key Laboratory of Green Prevention and Control on Fruits and Vegetables in South China, Ministry of Agriculture and Rural Affairs, Guangzhou, Guangdong, 510642, China
| | - Guo Wei
- Department of Plant Sciences, University of Tennessee, Knoxville, Tennessee, 37996, USA
| | - Feng Chen
- Department of Plant Sciences, University of Tennessee, Knoxville, Tennessee, 37996, USA
| | - Liang Zeng
- Biozeron Biotech. Co., Ltd., Shanghai, 200120, China
| | - Hong Lin
- San Joaquin Valley Agricultural Sciences Center, USDA-ARS, Parlier, California, 93658, USA
| | - Ayesha Baig
- Department of Biotechnology, COMSATS University Islamabad Abbottabad Campus, Abbottabad, KPK, 22010, Pakistan
| | - Xuefeng Wang
- National Citrus Engineering Research Center, Citrus Research Institute, Southwest University, Beibei, Chongqing, 400712, China
| | - Xiuping Zou
- National Citrus Engineering Research Center, Citrus Research Institute, Southwest University, Beibei, Chongqing, 400712, China
| | - Hongwei Zhao
- College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, 210095, China
| |
Collapse
|
6
|
Nehela Y, Killiny N. Gamma-Aminobutyric Acid Supplementation Boosts the Phytohormonal Profile in ' Candidatus Liberibacter asiaticus'-Infected Citrus. PLANTS (BASEL, SWITZERLAND) 2023; 12:3647. [PMID: 37896110 PMCID: PMC10609878 DOI: 10.3390/plants12203647] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 10/17/2023] [Accepted: 10/18/2023] [Indexed: 10/29/2023]
Abstract
The devastating citrus disease, Huanglongbing (HLB), is associated with 'Candidatus Liberibacter sp.' and transmitted by citrus psyllids. Unfortunately, HLB has no known sustainable cure yet. Herein, we proposed γ-aminobutyric acid (GABA) as a potential eco-friendly therapeutic solution to HLB. Herein, we used GC/MS-based targeted metabolomics combined with gene expression to investigate the role of GABA in citrus response against HLB and to better understand its relationship(s) with different phytohormones. GABA supplementation via root drench boosts the accumulation of endogenous GABA in the leaves of both healthy and 'Ca. L. asiaticus'-infected trees. GABA accumulation benefits the activation of a multi-layered defensive system via modulating the phytohormone levels and regulating the expression of their biosynthesis genes and some pathogenesis-related proteins (PRs) in both healthy and 'Ca. L. asiaticus'-infected plants. Moreover, our findings showed that GABA application stimulates auxin biosynthesis in 'Ca. L. asiaticus'-infected plants via the activation of the indole-3-pyruvate (I3PA) pathway, not via the tryptamine (TAM)-dependent pathway, to enhance the growth of HLB-affected trees. Likewise, GABA accumulation was associated with the upregulation of SA biosynthesis genes, particularly the PAL-dependent route, resulting in higher SA levels that activated CsPR1, CsPR2, CsPR5, and CsWRKY70, which are prominent to activation of the SA-mediated pathway. Additionally, higher GABA levels were correlated with an enhanced JA profile and linked with both CsPR3 and CsPR4, which activates the JA-mediated pathway. Collectively, our findings suggest that exogenous GABA application might be a promising alternative and eco-friendly strategy that helps citrus trees battle HLB.
Collapse
Affiliation(s)
- Yasser Nehela
- Department of Plant Pathology, Citrus Research and Education Center, University of Florida, 700 Experiment Station Rd., Lake Alfred, FL 33850, USA;
- Department of Agricultural Botany, Faculty of Agriculture, Tanta University, Tanta 31527, Egypt
| | - Nabil Killiny
- Department of Plant Pathology, Citrus Research and Education Center, University of Florida, 700 Experiment Station Rd., Lake Alfred, FL 33850, USA;
| |
Collapse
|
7
|
Zhang S, Wang X, He J, Zhang S, Zhao T, Fu S, Zhou C. A Sec-dependent effector, CLIBASIA_04425, contributes to virulence in ' Candidatus Liberibater asiaticus'. FRONTIERS IN PLANT SCIENCE 2023; 14:1224736. [PMID: 37554557 PMCID: PMC10405523 DOI: 10.3389/fpls.2023.1224736] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Accepted: 07/05/2023] [Indexed: 08/10/2023]
Abstract
Citrus Huanglongbing (HLB) is the most destructive citrus disease worldwide, mainly caused by 'Candidatus Liberibacter asiaticus' (CLas). It encodes a large number of Sec-dependent effectors that contribute to HLB progression. In this study, an elicitor triggering ROS burst and cell death in Nicotiana benthamiana, CLIBASIA_04425 (CLas4425), was identified. Of particular interest, its cell death-inducing activity is associated with its subcellular localization and the cytoplasmic receptor Botrytis-induced kinase 1 (BIK1). Compared with CLas infected psyllids, CLas4425 showed higher expression level in planta. The transient expression of CLas4425 in N. benthamiana and its overexpression in Citrus sinensis enhanced plant susceptibility to Pseudomonas syringae pv. tomato DC3000 ΔhopQ1-1 and CLas, respectively. Furthermore, the salicylic acid (SA) level along with the expression of genes NPR1/EDS1/NDR1/PRs in SA signal transduction was repressed in CLas4425 transgenic citrus plants. Taken together, CLas4425 is a virulence factor that promotes CLas proliferation, likely by interfering with SA-mediated plant immunity. The results obtained facilitate our understanding of CLas pathogenesis.
Collapse
Affiliation(s)
- Shushe Zhang
- Citrus Research Institute, Southwest University/National Citrus Engineering Research Center, Chongqing, China
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Chinese Academy of Agriculture Sciences, Institute of Plant Protection, Beijing, China
| | - Xuefeng Wang
- Citrus Research Institute, Southwest University/National Citrus Engineering Research Center, Chongqing, China
| | - Jun He
- Citrus Research Institute, Southwest University/National Citrus Engineering Research Center, Chongqing, China
| | - Song Zhang
- Guangxi Citrus Breeding and Cultivation Engineering Technology Center Academy of Specialty Crops, Guangxi, Guilin, China
| | - Tingchang Zhao
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Chinese Academy of Agriculture Sciences, Institute of Plant Protection, Beijing, China
| | - Shimin Fu
- Citrus Research Institute, Southwest University/National Citrus Engineering Research Center, Chongqing, China
| | - Changyong Zhou
- Citrus Research Institute, Southwest University/National Citrus Engineering Research Center, Chongqing, China
| |
Collapse
|
8
|
Zheng Y, Zhang J, Li Y, Liu Y, Liang J, Wang C, Fang F, Deng X, Zheng Z. Pathogenicity and Transcriptomic Analyses of Two " Candidatus Liberibacter asiaticus" Strains Harboring Different Types of Phages. Microbiol Spectr 2023; 11:e0075423. [PMID: 37071011 PMCID: PMC10269750 DOI: 10.1128/spectrum.00754-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Accepted: 03/31/2023] [Indexed: 04/19/2023] Open
Abstract
"Candidatus Liberibacter asiaticus" is one of the putative causal agents of citrus Huanglongbing (HLB), a highly destructive disease threatening the global citrus industry. Several types of phages had been identified in "Ca. Liberibacter asiaticus" strains and found to affect the biology of "Ca. Liberibacter asiaticus." However, little is known about the influence of phages in "Ca. Liberibacter asiaticus" pathogenicity. In this study, two "Ca. Liberibacter asiaticus" strains, PYN and PGD, harboring different types of phages were collected and used for pathogenicity analysis in periwinkle (Catharanthus roseus). Strain PYN carries a type 1 phage (P-YN-1), and PGD harbors a type 2 phage (P-GD-2). Compared to strain PYN, strain PGD exhibited a faster reproduction rate and higher virulence in periwinkle: leaf symptoms appeared earlier, and there was a stronger inhibition in the growth of new flush. Estimation of phage copy numbers by type-specific PCR indicated that there are multiple copies of phage P-YN-1 in strain PYN, while strain PGD carries only a single copy of phage P-GD-2. Genome-wide gene expression profiling revealed the lytic activity of P-YN-1 phage, as evidenced by the unique expression of genes involved in lytic cycle, which may limit the propagation of strain PYN and lead to a delayed infection in periwinkle. However, the activation of genes involved in lysogenic conversion of phage P-GD-1 indicated it could reside within the "Ca. Liberibacter asiaticus" genome as a prophage form in strain PGD. Comparative transcriptome analysis showed that the significant differences in expression of virulence factor genes, including genes associated with pathogenic effectors, transcriptional factors, the Znu transport system, and the heme biosynthesis pathway, could be another major determinant of virulence variation between two "Ca. Liberibacter asiaticus" strains. This study expanded our knowledge of "Ca. Liberibacter asiaticus" pathogenicity and provided new insights into the differences in pathogenicity between "Ca. Liberibacter asiaticus" strains. IMPORTANCE Citrus Huanglongbing (HLB), also called citrus greening disease, is a highly destructive disease threatening citrus production worldwide. "Candidatus Liberibacter asiaticus" is one of the most common putative causal agents of HLB. Phages of "Ca. Liberibacter asiaticus" have recently been identified and found to affect "Ca. Liberibacter asiaticus" biology. Here, we found that "Ca. Liberibacter asiaticus" strains harboring different types of phages (type 1 or type 2) showed different levels of pathogenicity and multiplication patterns in the periwinkle plant (Catharanthus roseus). Transcriptome analysis revealed the possible lytic activity of type 1 phage in a "Ca. Liberibacter asiaticus" strain, which could limit the propagation of "Ca. Liberibacter asiaticus" and lead to the delayed infection in periwinkle. The heterogeneity in the transcriptome profiles, particularly the significant differences in expression of virulence factors genes, could be another major determinant of difference in virulence observed between the two "Ca. Liberibacter asiaticus" strains. These findings improved our understanding of "Ca. Liberibacter asiaticus"-phage interaction and provided insight into "Ca. Liberibacter asiaticus" pathogenicity.
Collapse
Affiliation(s)
- Yongqin Zheng
- National Key Laboratory of Green Pesticide, South China Agricultural University, Guangzhou, Guangdong, China
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, Guangdong, China
| | - Jingxue Zhang
- National Key Laboratory of Green Pesticide, South China Agricultural University, Guangzhou, Guangdong, China
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, Guangdong, China
| | - Yun Li
- National Key Laboratory of Green Pesticide, South China Agricultural University, Guangzhou, Guangdong, China
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, Guangdong, China
| | - Yaoxin Liu
- Horticulture Research Institute, Guangxi Academy of Agricultural Sciences, Nanning, Guangxi, China
| | - Jiayin Liang
- National Key Laboratory of Green Pesticide, South China Agricultural University, Guangzhou, Guangdong, China
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, Guangdong, China
| | - Cheng Wang
- National Key Laboratory of Green Pesticide, South China Agricultural University, Guangzhou, Guangdong, China
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, Guangdong, China
| | - Fang Fang
- National Key Laboratory of Green Pesticide, South China Agricultural University, Guangzhou, Guangdong, China
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, Guangdong, China
| | - Xiaoling Deng
- National Key Laboratory of Green Pesticide, South China Agricultural University, Guangzhou, Guangdong, China
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, Guangdong, China
| | - Zheng Zheng
- National Key Laboratory of Green Pesticide, South China Agricultural University, Guangzhou, Guangdong, China
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, Guangdong, China
| |
Collapse
|
9
|
Pandey SS, Xu J, Achor DS, Li J, Wang N. Microscopic and Transcriptomic Analyses of Early Events Triggered by ' Candidatus Liberibacter asiaticus' in Young Flushes of Huanglongbing-Positive Citrus Trees. PHYTOPATHOLOGY 2023; 113:985-997. [PMID: 36449527 DOI: 10.1094/phyto-10-22-0360-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
'Candidatus Liberibacter asiaticus' (CLas) is associated with the devastating citrus disease Huanglongbing (HLB). Young flushes are the center of the HLB pathosystem due to their roles in the psyllid life cycle and in the acquisition and transmission of CLas. However, the early events of CLas infection and how CLas modulates young flush physiology remain poorly understood. Here, transmission electron microscopy analysis showed that the mean diameter of the sieve pores decreased in young leaves of HLB-positive trees after CLas infection, consistent with CLas-triggered callose deposition. RNA-seq-based global expression analysis of young leaves of HLB-positive sweet orange with (CLas-Pos) and without (CLas-Neg) detectable CLas demonstrated a significant impact on gene expression in young leaves, including on the expression of genes involved in host immunity, stress response, and plant hormone biosynthesis and signaling. CLas-Pos and CLas-Neg expression data displayed distinct patterns. The number of upregulated genes was higher than that of the downregulated genes in CLas-Pos for plant-pathogen interactions, glutathione metabolism, peroxisome, and calcium signaling, which are commonly associated with pathogen infections, compared with the healthy control. On the contrary, the number of upregulated genes was lower than that of the downregulated genes in CLas-Neg for genes involved in plant-pathogen interactions and peroxisome biogenesis/metabolism. Additionally, a time-course quantitative reverse transcription-PCR-based expression analysis visualized the induced expression of companion cell-specific genes, phloem protein 2 genes, and sucrose transport genes in young flushes triggered by CLas. This study advances our understanding of early events during CLas infection of citrus young flushes.
Collapse
Affiliation(s)
- Sheo Shankar Pandey
- Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Lake Alfred, FL 33850
| | - Jin Xu
- Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Lake Alfred, FL 33850
| | - Diann S Achor
- Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Lake Alfred, FL 33850
| | - Jinyun Li
- Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Lake Alfred, FL 33850
| | - Nian Wang
- Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Lake Alfred, FL 33850
| |
Collapse
|
10
|
Liu HQ, Zhao ZL, Li HJ, Yu SJ, Cong L, Ding LL, Ran C, Wang XF. Accurate prediction of huanglongbing occurrence in citrus plants by machine learning-based analysis of symbiotic bacteria. FRONTIERS IN PLANT SCIENCE 2023; 14:1129508. [PMID: 37313258 PMCID: PMC10258322 DOI: 10.3389/fpls.2023.1129508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 05/02/2023] [Indexed: 06/15/2023]
Abstract
Huanglongbing (HLB), the most prevalent citrus disease worldwide, is responsible for substantial yield and economic losses. Phytobiomes, which have critical effects on plant health, are associated with HLB outcomes. The development of a refined model for predicting HLB outbreaks based on phytobiome markers may facilitate early disease detection, thus enabling growers to minimize damages. Although some investigations have focused on differences in the phytobiomes of HLB-infected citrus plants and healthy ones, individual studies are inappropriate for generating common biomarkers useful for detecting HLB on a global scale. In this study, we therefore obtained bacterial information from several independent datasets representing hundreds of citrus samples from six continents and used these data to construct HLB prediction models based on 10 machine learning algorithms. We detected clear differences in the phyllosphere and rhizosphere microbiomes of HLB-infected and healthy citrus samples. Moreover, phytobiome alpha diversity indices were consistently higher for healthy samples. Furthermore, the contribution of stochastic processes to citrus rhizosphere and phyllosphere microbiome assemblies decreased in response to HLB. Comparison of all constructed models indicated that a random forest model based on 28 bacterial genera in the rhizosphere and a bagging model based on 17 bacterial species in the phyllosphere predicted the health status of citrus plants with almost 100% accuracy. Our results thus demonstrate that machine learning models and phytobiome biomarkers may be applied to evaluate the health status of citrus plants.
Collapse
Affiliation(s)
- Hao-Qiang Liu
- Citrus Research Institute, Southwest University/Chinese Academy of Agricultural Sciences, National Engineering Research Center for Citrus, Chongqing, China
| | - Ze-long Zhao
- Shanghai BIOZERON Biotechnology Co., Ltd., Shanghai, China
| | - Hong-Jun Li
- Citrus Research Institute, Southwest University/Chinese Academy of Agricultural Sciences, National Engineering Research Center for Citrus, Chongqing, China
| | - Shi-Jiang Yu
- Citrus Research Institute, Southwest University/Chinese Academy of Agricultural Sciences, National Engineering Research Center for Citrus, Chongqing, China
| | - Lin Cong
- Citrus Research Institute, Southwest University/Chinese Academy of Agricultural Sciences, National Engineering Research Center for Citrus, Chongqing, China
| | - Li-Li Ding
- Citrus Research Institute, Southwest University/Chinese Academy of Agricultural Sciences, National Engineering Research Center for Citrus, Chongqing, China
| | - Chun Ran
- Citrus Research Institute, Southwest University/Chinese Academy of Agricultural Sciences, National Engineering Research Center for Citrus, Chongqing, China
| | - Xue-Feng Wang
- Citrus Research Institute, Southwest University/Chinese Academy of Agricultural Sciences, National Engineering Research Center for Citrus, Chongqing, China
| |
Collapse
|
11
|
Ghosh D, Kokane S, Savita BK, Kumar P, Sharma AK, Ozcan A, Kokane A, Santra S. Huanglongbing Pandemic: Current Challenges and Emerging Management Strategies. PLANTS (BASEL, SWITZERLAND) 2022; 12:plants12010160. [PMID: 36616289 PMCID: PMC9824665 DOI: 10.3390/plants12010160] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 12/06/2022] [Accepted: 12/07/2022] [Indexed: 05/09/2023]
Abstract
Huanglongbing (HLB, aka citrus greening), one of the most devastating diseases of citrus, has wreaked havoc on the global citrus industry in recent decades. The culprit behind such a gloomy scenario is the phloem-limited bacteria "Candidatus Liberibacter asiaticus" (CLas), which are transmitted via psyllid. To date, there are no effective long-termcommercialized control measures for HLB, making it increasingly difficult to prevent the disease spread. To combat HLB effectively, introduction of multipronged management strategies towards controlling CLas population within the phloem system is deemed necessary. This article presents a comprehensive review of up-to-date scientific information about HLB, including currently available management practices and unprecedented challenges associated with the disease control. Additionally, a triangular disease management approach has been introduced targeting pathogen, host, and vector. Pathogen-targeting approaches include (i) inhibition of important proteins of CLas, (ii) use of the most efficient antimicrobial or immunity-inducing compounds to suppress the growth of CLas, and (iii) use of tools to suppress or kill the CLas. Approaches for targeting the host include (i) improvement of the host immune system, (ii) effective use of transgenic variety to build the host's resistance against CLas, and (iii) induction of systemic acquired resistance. Strategies for targeting the vector include (i) chemical and biological control and (ii) eradication of HLB-affected trees. Finally, a hypothetical model for integrated disease management has been discussed to mitigate the HLB pandemic.
Collapse
Affiliation(s)
- Dilip Ghosh
- Plant Virology Laboratory, ICAR-Central Citrus Research Institute, Nagpur 440033, India
- Correspondence: (D.G.); (A.K.S.); (S.S.)
| | - Sunil Kokane
- Plant Virology Laboratory, ICAR-Central Citrus Research Institute, Nagpur 440033, India
| | - Brajesh Kumar Savita
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Roorkee 247667, India
| | - Pranav Kumar
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Roorkee 247667, India
| | - Ashwani Kumar Sharma
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Roorkee 247667, India
- Correspondence: (D.G.); (A.K.S.); (S.S.)
| | - Ali Ozcan
- Vocational School of Technical Sciences, Karamanoglu Mehmetbey University, 70200 Karaman, Turkey
- Scientific and Technological Studies Application and Research Center, Karamanoglu Mehmetbey University, 70200 Karaman, Turkey
| | - Amol Kokane
- Plant Virology Laboratory, ICAR-Central Citrus Research Institute, Nagpur 440033, India
| | - Swadeshmukul Santra
- Departments of Chemistry, Nano Science Technology Center, and Burnett School of Biomedical Sciences, University of Central Florida, Orlando, FL 32816, USA
- Correspondence: (D.G.); (A.K.S.); (S.S.)
| |
Collapse
|
12
|
Bernardini C, Turner D, Wang C, Welker S, Achor D, Artiga YA, Turgeon R, Levy A. Candidatus Liberibacter asiaticus accumulation in the phloem inhibits callose and reactive oxygen species. PLANT PHYSIOLOGY 2022; 190:1090-1094. [PMID: 35880843 PMCID: PMC9516723 DOI: 10.1093/plphys/kiac346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 06/30/2022] [Indexed: 06/15/2023]
Abstract
CLas inhibits callose deposition in the sieve pores and the accumulation of reactive oxygen species to favor its cell-to-cell movement.
Collapse
Affiliation(s)
- Chiara Bernardini
- Citrus Research and Education Center, University of Florida, Lake Alfred, Florida 33850, USA
| | - Donielle Turner
- Citrus Research and Education Center, University of Florida, Lake Alfred, Florida 33850, USA
| | - Chunxia Wang
- Citrus Research and Education Center, University of Florida, Lake Alfred, Florida 33850, USA
| | - Stacy Welker
- Citrus Research and Education Center, University of Florida, Lake Alfred, Florida 33850, USA
| | - Diann Achor
- Citrus Research and Education Center, University of Florida, Lake Alfred, Florida 33850, USA
| | - Yosvanis Acanda Artiga
- Citrus Research and Education Center, University of Florida, Lake Alfred, Florida 33850, USA
| | - Robert Turgeon
- School of Integrative Plant Science, Plant Biology Section, Cornell University, Ithaca, New York 14853, USA
| | | |
Collapse
|
13
|
Abstract
Although the phloem is a highly specialized tissue, certain pathogens, including phytoplasmas, spiroplasmas, and viruses, have evolved to access and live in this sequestered and protected environment, causing substantial economic harm. In particular, Candidatus Liberibacter spp. are devastating citrus in many parts of the world. Given that most phloem pathogens are vectored, they are not exposed to applied chemicals and are therefore difficult to control. Furthermore, pathogens use the phloem network to escape mounted defenses. Our review summarizes the current knowledge of phloem anatomy, physiology, and biochemistry relevant to phloem/pathogen interactions. We focus on aspects of anatomy specific to pathogen movement, including sieve plate structure and phloem-specific proteins. Phloem sampling techniques are discussed. Finally, pathogens that cause particular harm to the phloem of crop species are considered in detail.
Collapse
Affiliation(s)
- Jennifer D Lewis
- Plant Gene Expression Center, USDA-ARS, Albany, California, USA
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, California, USA
| | - Michael Knoblauch
- School of Biological Sciences, Washington State University, Pullman, Washington, USA
| | - Robert Turgeon
- Plant Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, New York, USA;
| |
Collapse
|
14
|
Jain M, Cai L, Black I, Azadi P, Carlson RW, Jones KM, Gabriel DW. ' Candidatus Liberibacter asiaticus'-Encoded BCP Peroxiredoxin Suppresses Lipopolysaccharide-Mediated Defense Signaling and Nitrosative Stress In Planta. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2022; 35:257-273. [PMID: 34931906 DOI: 10.1094/mpmi-09-21-0230-r] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The lipopolysaccharides (LPS) of gram-negative bacteria trigger a nitrosative and oxidative burst in both animals and plants during pathogen invasion. Liberibacter crescens strain BT-1 is a surrogate for functional genomic studies of the uncultured pathogenic 'Candidatus Liberibacter' spp. that are associated with severe diseases such as citrus greening and potato zebra chip. Structural determination of L. crescens LPS revealed the presence of a very long chain fatty acid modification. L. crescens LPS pretreatment suppressed growth of Xanthomonas perforans on nonhost tobacco (Nicotiana benthamiana) and X. citri subsp. citri on host orange (Citrus sinensis), confirming bioactivity of L. crescens LPS in activation of systemic acquired resistance (SAR). L. crescens LPS elicited a rapid burst of nitric oxide (NO) in suspension cultured tobacco cells. Pharmacological inhibitor assays confirmed that arginine-utilizing NO synthase (NOS) activity was the primary source of NO generation elicited by L. crescens LPS. LPS treatment also resulted in biological markers of NO-mediated SAR activation, including an increase in the glutathione pool, callose deposition, and activation of the salicylic acid and azelaic acid (AzA) signaling networks. Transient expression of 'Ca. L. asiaticus' bacterioferritin comigratory protein (BCP) peroxiredoxin in tobacco compromised AzA signaling, a prerequisite for LPS-triggered SAR. Western blot analyses revealed that 'Ca. L. asiaticus' BCP peroxiredoxin prevented peroxynitrite-mediated tyrosine nitration in tobacco. 'Ca. L. asiaticus' BCP peroxiredoxin (i) attenuates NO-mediated SAR signaling and (ii) scavenges peroxynitrite radicals, which would facilitate repetitive cycles of 'Ca. L. asiaticus' acquisition and transmission by fecund psyllids throughout the limited flush period in citrus.[Formula: see text] Copyright © 2022 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
Collapse
Affiliation(s)
- Mukesh Jain
- Plant Pathology Department, University of Florida, Gainesville, FL 32611, U.S.A
| | - Lulu Cai
- Plant Pathology Department, University of Florida, Gainesville, FL 32611, U.S.A
| | - Ian Black
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, U.S.A
| | - Parastoo Azadi
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, U.S.A
| | - Russell W Carlson
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, U.S.A
| | - Kathryn M Jones
- Department of Biological Science, Florida State University, Tallahassee, FL 32306, U.S.A
| | - Dean W Gabriel
- Plant Pathology Department, University of Florida, Gainesville, FL 32611, U.S.A
| |
Collapse
|
15
|
Du M, Wang S, Dong L, Qu R, Zheng L, He Y, Chen S, Zou X. Overexpression of a " Candidatus Liberibacter Asiaticus" Effector Gene CaLasSDE115 Contributes to Early Colonization in Citrus sinensis. Front Microbiol 2022; 12:797841. [PMID: 35265048 PMCID: PMC8899593 DOI: 10.3389/fmicb.2021.797841] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 12/20/2021] [Indexed: 11/29/2022] Open
Abstract
Huanglongbing (HLB), caused by "Candidatus liberibacter asiaticus" (CaLas), is one of the most devastating diseases in citrus but its pathogenesis remains poorly understood. Here, we reported the role of the CaLasSDE115 (CLIBASIA_05115) effector, encoded by CaLas, during pathogen-host interactions. Bioinformatics analyses showed that CaLasSDE115 was 100% conserved in all reported CaLas strains but had sequence differences compared with orthologs from other "Candidatus liberibacter." Prediction of protein structures suggested that the crystal structure of CaLasSDE115 was very close to that of the invasion-related protein B (IalB), a virulence factor from Bartonella henselae. Alkaline phosphatase (PhoA) assay in E. coli further confirmed that CaLasSDE115 was a Sec-dependent secretory protein while subcellular localization analyses in tobacco showed that the mature protein of SDE115 (mSDE115), without its putative Sec-dependent signal peptide, was distributed in the cytoplasm and the nucleus. Expression levels of CaLasSDE115 in CaLas-infected Asian citrus psyllid (ACP) were much higher (∼45-fold) than those in CaLas-infected Wanjincheng oranges, with the expression in symptomatic leaves being significantly higher than that in asymptomatic ones. Additionally, the overexpression of mSDE115 favored CaLas proliferation during the early stages (2 months) of infection while promoting the development of symptoms. Hormone content and gene expression analysis of transgenic plants also suggested that overexpressing mSDE115 modulated the transcriptional regulation of genes involved in systemic acquired resistance (SAR) response. Overall, our data indicated that CaLasSDE115 effector contributed to the early colonization of citrus by the pathogen and worsened the occurrence of Huanglongbing symptoms, thereby providing a theoretical basis for further exploring the pathogenic mechanisms of Huanglongbing disease in citrus.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | - Xiuping Zou
- National Citrus Engineering Research Center, Citrus Research Institute, Southwest University, Chongqing, China
| |
Collapse
|
16
|
Ma W, Pang Z, Huang X, Xu J, Pandey SS, Li J, Achor DS, Vasconcelos FNC, Hendrich C, Huang Y, Wang W, Lee D, Stanton D, Wang N. Citrus Huanglongbing is a pathogen-triggered immune disease that can be mitigated with antioxidants and gibberellin. Nat Commun 2022; 13:529. [PMID: 35082290 PMCID: PMC8791970 DOI: 10.1038/s41467-022-28189-9] [Citation(s) in RCA: 42] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 01/04/2022] [Indexed: 12/17/2022] Open
Abstract
Huanglongbing (HLB) is a devastating disease of citrus, caused by the phloem-colonizing bacterium Candidatus Liberibacter asiaticus (CLas). Here, we present evidence that HLB is an immune-mediated disease. We show that CLas infection of Citrus sinensis stimulates systemic and chronic immune responses in phloem tissue, including callose deposition, production of reactive oxygen species (ROS) such as H2O2, and induction of immunity-related genes. The infection also upregulates genes encoding ROS-producing NADPH oxidases, and downregulates antioxidant enzyme genes, supporting that CLas causes oxidative stress. CLas-triggered ROS production localizes in phloem-enriched bark tissue and is followed by systemic cell death of companion and sieve element cells. Inhibition of ROS levels in CLas-positive stems by NADPH oxidase inhibitor diphenyleneiodonium (DPI) indicates that NADPH oxidases contribute to CLas-triggered ROS production. To investigate potential treatments, we show that addition of the growth hormone gibberellin (known to have immunoregulatory activities) upregulates genes encoding H2O2-scavenging enzymes and downregulates NADPH oxidases. Furthermore, foliar spray of HLB-affected citrus with gibberellin or antioxidants (uric acid, rutin) reduces H2O2 concentrations and cell death in phloem tissues and reduces HLB symptoms. Thus, our results indicate that HLB is an immune-mediated disease that can be mitigated with antioxidants and gibberellin.
Collapse
Affiliation(s)
- Wenxiu Ma
- Citrus Research and Education Center, Department of Microbiology and Cell Science, IFAS, University of Florida, Lake Alfred, FL, USA
| | - Zhiqian Pang
- Citrus Research and Education Center, Department of Microbiology and Cell Science, IFAS, University of Florida, Lake Alfred, FL, USA
| | - Xiaoen Huang
- Citrus Research and Education Center, Department of Microbiology and Cell Science, IFAS, University of Florida, Lake Alfred, FL, USA
| | - Jin Xu
- Citrus Research and Education Center, Department of Microbiology and Cell Science, IFAS, University of Florida, Lake Alfred, FL, USA
| | - Sheo Shankar Pandey
- Citrus Research and Education Center, Department of Microbiology and Cell Science, IFAS, University of Florida, Lake Alfred, FL, USA
| | - Jinyun Li
- Citrus Research and Education Center, Department of Microbiology and Cell Science, IFAS, University of Florida, Lake Alfred, FL, USA
| | - Diann S Achor
- Citrus Research and Education Center, Department of Microbiology and Cell Science, IFAS, University of Florida, Lake Alfred, FL, USA
| | - Fernanda N C Vasconcelos
- Citrus Research and Education Center, Department of Microbiology and Cell Science, IFAS, University of Florida, Lake Alfred, FL, USA
| | - Connor Hendrich
- Citrus Research and Education Center, Department of Microbiology and Cell Science, IFAS, University of Florida, Lake Alfred, FL, USA
| | - Yixiao Huang
- Citrus Research and Education Center, Department of Microbiology and Cell Science, IFAS, University of Florida, Lake Alfred, FL, USA
| | - Wenting Wang
- Citrus Research and Education Center, Department of Microbiology and Cell Science, IFAS, University of Florida, Lake Alfred, FL, USA
| | - Donghwan Lee
- Citrus Research and Education Center, Department of Microbiology and Cell Science, IFAS, University of Florida, Lake Alfred, FL, USA
| | - Daniel Stanton
- Citrus Research and Education Center, Department of Microbiology and Cell Science, IFAS, University of Florida, Lake Alfred, FL, USA
| | - Nian Wang
- Citrus Research and Education Center, Department of Microbiology and Cell Science, IFAS, University of Florida, Lake Alfred, FL, USA.
| |
Collapse
|
17
|
Ibanez F, Suh JH, Wang Y, Rivera M, Setamou M, Stelinski LL. Salicylic acid mediated immune response of Citrus sinensis to varying frequencies of herbivory and pathogen inoculation. BMC PLANT BIOLOGY 2022; 22:7. [PMID: 34979915 PMCID: PMC8722004 DOI: 10.1186/s12870-021-03389-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 12/08/2021] [Indexed: 05/07/2023]
Abstract
BACKGROUND Plant immunity against pathogens and pests is comprised of complex mechanisms orchestrated by signaling pathways regulated by plant hormones [Salicylic acid (SA) and Jasmonic acid (JA)]. Investigations of plant immune response to phytopathogens and phloem-feeders have revealed that SA plays a critical role in reprogramming of the activity and/or localization of transcriptional regulators via post-translational modifications. We explored the contributing effects of herbivory by a phytopathogen vector [Asian citrus psyllid, Diaphorina citri] and pathogen [Candidatus Liberibacter asiaticus (CaLas)] infection on response of sweet orange [Citrus sinensis (L.) Osbeck] using manipulative treatments designed to mimic the types of infestations/infections that citrus growers experience when cultivating citrus in the face of Huanglongbing (HLB) disease. RESULTS A one-time (7 days) inoculation access period with CaLas-infected vectors caused SA-associated upregulation of PR-1, stimulating defense response after a long period of infection without herbivory (270 and 360 days). In contrast, while repeated (monthly) 'pulses' of 7 day feeding injury by psyllids stimulated immunity in CaLas-infected citrus by increasing SA in leaves initially (up to 120 days), long-term (270 and 360 days) repeated herbivory caused SA to decrease coincident with upregulation of genes associated with SA metabolism (BMST and DMR6). Similarly, transcriptional responses and metabolite (SA and its analytes) accumulation in citrus leaves exposed to a continuously reproducing population of D. citri exhibited a transitory upregulation of genes associated with SA signaling at 120 days and a posterior downregulation after long-term psyllid (adults and nymphs) feeding (270 and 360 days). CONCLUSIONS Herbivory played an important role in regulation of SA accumulation in mature leaves of C. sinensis, whether or not those trees were coincidentally infected with CaLas. Our results indicate that prevention of feeding injury inflicted by D. citri from the tritrophic interaction may allow citrus plants to better cope with the consequences of CaLas infection, highlighting the importance of vector suppression as a component of managing this cosmopolitan disease.
Collapse
Affiliation(s)
- Freddy Ibanez
- Department of Entomology and Nematology, Citrus Research and Education Center, University of Florida, Lake Alfred, Florida, 33850 USA
- Present address: Texas A&M University-AgriLife Research, 2415 E Highway 83 –, Weslaco, TX 78596 USA
| | - Joon Hyuk Suh
- Department of Food Science and Human Nutrition, Citrus Research and Education Center, University of Florida, Lake Alfred, Florida, 33850 USA
| | - Yu Wang
- Department of Food Science and Human Nutrition, Citrus Research and Education Center, University of Florida, Lake Alfred, Florida, 33850 USA
| | - Monique Rivera
- Department of Entomology, University of California Riverside, Riverside, California, 92521 USA
| | - Mamoudou Setamou
- Texas A&M University-Kingsville Citrus Center, 312 N International Blvd, Weslaco, TX 78599 USA
| | - Lukasz L. Stelinski
- Department of Entomology and Nematology, Citrus Research and Education Center, University of Florida, Lake Alfred, Florida, 33850 USA
| |
Collapse
|
18
|
Killiny N. Generous Hosts: ' Candidatus Liberibacter asiaticus' Growth in Madagascar Periwinkle ( Catharanthus roseus) Highlights Its Nutritional Needs. PHYTOPATHOLOGY 2022; 112:89-100. [PMID: 34598662 DOI: 10.1094/phyto-05-21-0200-fi] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
'Candidatus Liberibacter asiaticus', the putative causal agent of citrus greening, is not available in pure culture yet. In addition to trees of citrus and citrus relatives, 'Ca. L. asiaticus' can grow in Madagascar periwinkle (Catharanthus roseus). Using gas chromatography-mass spectrometry, we compared the phloem sap composition in sweet orange 'Valencia' (Citrus sinensis) and periwinkle plants after the infection with 'Ca. L. asiaticus'. Interestingly, in contrast to our previous studies of total leaf metabolites, we found that, compared with uninfected phloem sap, the organic acids implicated in the tricarboxylic acid cycle (TCA) cycle including citrate, isocitrate, succinate, fumarate, and malate were reduced significantly in the infected phloem saps of both species. As a result of the reduction of organic acids content, the pH of infected phloem saps was increased. We hypothesize that the bacterial growth induces the mitochondrial TCA cycle in parenchyma cells to produce more of these compounds to be used as a bacterial carbon source. Once these compounds reach a low level in the phloem sap, the bacterium may send a signal, yet to be identified, to initiate a feedback loop to further induce the TCA cycle. Phloem blockage might be another reason behind the reduced translocation of TCA cycle intermediates within the phloem. The net result, localized availability of organic acids, likely benefits bacterial growth and may explain the unequal distribution of 'Ca. L. asiaticus' within infected trees. These findings may help in designing media for the pure culturing of 'Ca. L. asiaticus'.
Collapse
Affiliation(s)
- Nabil Killiny
- Department of Plant Pathology, Citrus Research and Education Center, IFAS, University of Florida, Lake Alfred, FL 33850
| |
Collapse
|
19
|
Pandey SS, Hendrich C, Andrade MO, Wang N. Candidatus Liberibacter: From Movement, Host Responses, to Symptom Development of Citrus Huanglongbing. PHYTOPATHOLOGY 2022; 112:55-68. [PMID: 34609203 DOI: 10.1094/phyto-08-21-0354-fi] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Candidatus Liberibacter spp. are fastidious α-proteobacteria that cause multiple diseases on plant hosts of economic importance, including the most devastating citrus disease: Huanglongbing (HLB). HLB was reported in Asia a century ago but has since spread worldwide. Understanding the pathogenesis of Candidatus Liberibacter spp. remains challenging as they are yet to be cultured in artificial media and infect the phloem, a sophisticated environment that is difficult to manipulate. Despite those challenges, tremendous progress has been made on Ca. Liberibacter pathosystems. Here, we first reviewed recent studies on genetic information of flagellar and type IV pili biosynthesis, their expression profiles, and movement of Ca. Liberibacter spp. inside the plant and insect hosts. Next, we reviewed the transcriptomic, proteomic, and metabolomic studies of susceptible and tolerant plant genotypes to Ca. Liberibacter spp. infection and how Ca. Liberibacter spp. adapt in plants. Analyses of the interactions between plants and Ca. Liberibacter spp. imply the involvement of immune response in the Ca. Liberibacter pathosystems. Lastly, we reviewed how Ca. Liberibacter spp. movement inside and interactions with plants lead to symptom development.
Collapse
Affiliation(s)
- Sheo Shankar Pandey
- Citrus Research and Education Center, Department of Microbiology and Cell Sciences, University of Florida, Lake Alfred, FL 33850, U.S.A
| | - Connor Hendrich
- Citrus Research and Education Center, Department of Microbiology and Cell Sciences, University of Florida, Lake Alfred, FL 33850, U.S.A
| | - Maxuel O Andrade
- Brazilian Biorenewables National Laboratory (LNBR), Brazilian Centre for Research in Energy and Materials (CNPEM), Campinas, SP, Brazil
| | - Nian Wang
- Citrus Research and Education Center, Department of Microbiology and Cell Sciences, University of Florida, Lake Alfred, FL 33850, U.S.A
| |
Collapse
|
20
|
De Francesco A, Lovelace AH, Shaw D, Qiu M, Wang Y, Gurung F, Ancona V, Wang C, Levy A, Jiang T, Ma W. Transcriptome Profiling of ' Candidatus Liberibacter asiaticus' in Citrus and Psyllids. PHYTOPATHOLOGY 2022; 112:116-130. [PMID: 35025694 DOI: 10.1094/phyto-08-21-0327-fi] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
'Candidatus Liberibacter asiaticus' (Las) is an emergent bacterial pathogen that is associated with the devastating citrus huanglongbing (HLB). Vectored by the Asian citrus psyllid, Las colonizes the phloem tissue of citrus, causing severe damage to infected trees. So far, cultivating pure Las culture in axenic media has not been successful, and dual-transcriptome analyses aiming to profile gene expression in both Las and its hosts have a low coverage of the Las genome because of the low abundance of bacterial RNA in total RNA extracts from infected tissues. Therefore, a lack of understanding of the Las transcriptome remains a significant knowledge gap. Here, we used a bacterial cell enrichment procedure and confidently determined the expression profiles of approximately 84% of the Las genes. Genes that exhibited high expression in citrus include transporters, ferritin, outer membrane porins, specific pilins, and genes involved in phage-related functions, cell wall modification, and stress responses. We also found 106 genes to be differentially expressed in citrus versus Asian citrus psyllids. Genes related to transcription or translation and resilience to host defense response were upregulated in citrus, whereas genes involved in energy generation and the flagella system were expressed to higher levels in psyllids. Finally, we determined the relative expression levels of potential Sec-dependent effectors, which are considered as key virulence factors of Las. This work advances our understanding of HLB biology and offers novel insight into the interactions of Las with its plant host and insect vector.
Collapse
Affiliation(s)
- Agustina De Francesco
- Department of Microbiology and Plant Pathology, University of California, Riverside, CA 92521, U.S.A
| | - Amelia H Lovelace
- The Sainsbury Laboratory, Norwich Research Park, NR4 7UH, United Kingdom
| | - Dipan Shaw
- Department of Computer Science and Engineering, University of California, Riverside, CA 92521, U.S.A
| | - Min Qiu
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Yuanchao Wang
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Fatta Gurung
- Citrus Center, Department of Agriculture, Agribusiness and Environmental Sciences, Texas A&M University-Kingsville, Weslaco, TX 78599, U.S.A
| | - Veronica Ancona
- Citrus Center, Department of Agriculture, Agribusiness and Environmental Sciences, Texas A&M University-Kingsville, Weslaco, TX 78599, U.S.A
| | - Chunxia Wang
- Citrus Research and Education Center, University of Florida, Lake Alfred, FL 33850, U.S.A
| | - Amit Levy
- Citrus Research and Education Center, University of Florida, Lake Alfred, FL 33850, U.S.A
| | - Tao Jiang
- Department of Computer Science and Engineering, University of California, Riverside, CA 92521, U.S.A
| | - Wenbo Ma
- Department of Microbiology and Plant Pathology, University of California, Riverside, CA 92521, U.S.A
- The Sainsbury Laboratory, Norwich Research Park, NR4 7UH, United Kingdom
| |
Collapse
|
21
|
Wu T, Zhang H, Bi Y, Yu Y, Liu H, Yang H, Yuan B, Ding X, Chu Z. Tal2c Activates the Expression of OsF3H04g to Promote Infection as a Redundant TALE of Tal2b in Xanthomonas oryzae pv. oryzicola. Int J Mol Sci 2021; 22:ijms222413628. [PMID: 34948428 PMCID: PMC8707247 DOI: 10.3390/ijms222413628] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Revised: 12/15/2021] [Accepted: 12/16/2021] [Indexed: 12/11/2022] Open
Abstract
Xanthomonas oryzae delivers transcription activator-like effectors (TALEs) into plant cells to facilitate infection. Following economic principles, the redundant TALEs are rarely identified in Xanthomonas. Previously, we identified the Tal2b, which activates the expression of the rice 2-oxoglutarate-dependent dioxygenase gene OsF3H03g to promote infection in the highly virulent strain of X. oryzae pv. oryzicola HGA4. Here, we reveal that another clustered TALE, Tal2c, also functioned as a virulence factor to target rice OsF3H04g, a homologue of OsF3H03g. Transferring Tal2c into RS105 induced expression of OsF3H04g to coincide with increased susceptibility in rice. Overexpressing OsF3H04g caused higher susceptibility and less salicylic acid (SA) production compared to wild-type plants. Moreover, CRISPR–Cas9 system-mediated editing of the effector-binding element in the promoters of OsF3H03g or OsF3H04g was found to specifically enhance resistance to Tal2b- or Tal2c-transferring strains, but had no effect on resistance to either RS105 or HGA4. Furthermore, transcriptome analysis revealed that several reported SA-related and defense-related genes commonly altered expression in OsF3H04g overexpression line compared with those identified in OsF3H03g overexpression line. Overall, our results reveal a functional redundancy mechanism of pathogenic virulence in Xoc in which tandem Tal2b and Tal2c specifically target homologues of host genes to interfere with rice immunity by reducing SA.
Collapse
Affiliation(s)
- Tao Wu
- State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai’an 271018, China; (T.W.); (H.Z.); (Y.Y.); (H.L.)
- State Key Laboratory of Hybrid Rice, Hubei Hongshan Laboratory, College of Life Sciences, Wuhan University, Wuhan 430072, China;
| | - Haimiao Zhang
- State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai’an 271018, China; (T.W.); (H.Z.); (Y.Y.); (H.L.)
- Shandong Provincial Key Laboratory for Biology of Vegetable Diseases and Insect Pests, College of Plant Protection, Shandong Agricultural University, Tai’an 271018, China
| | - Yunya Bi
- State Key Laboratory of Hybrid Rice, Hubei Hongshan Laboratory, College of Life Sciences, Wuhan University, Wuhan 430072, China;
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan 430062, China;
| | - Yue Yu
- State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai’an 271018, China; (T.W.); (H.Z.); (Y.Y.); (H.L.)
| | - Haifeng Liu
- State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai’an 271018, China; (T.W.); (H.Z.); (Y.Y.); (H.L.)
| | - Hong Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan 430062, China;
| | - Bin Yuan
- Institute of Plant Protection and Soil Fertilizer, Hubei Academy of Agricultural Sciences, Wuhan 430064, China;
| | - Xinhua Ding
- State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai’an 271018, China; (T.W.); (H.Z.); (Y.Y.); (H.L.)
- Shandong Provincial Key Laboratory for Biology of Vegetable Diseases and Insect Pests, College of Plant Protection, Shandong Agricultural University, Tai’an 271018, China
- Correspondence: (X.D.); (Z.C.); Tel.: +86-538-8245569 (X.D.); +86-27-68752095 (Z.C.)
| | - Zhaohui Chu
- State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai’an 271018, China; (T.W.); (H.Z.); (Y.Y.); (H.L.)
- State Key Laboratory of Hybrid Rice, Hubei Hongshan Laboratory, College of Life Sciences, Wuhan University, Wuhan 430072, China;
- Correspondence: (X.D.); (Z.C.); Tel.: +86-538-8245569 (X.D.); +86-27-68752095 (Z.C.)
| |
Collapse
|
22
|
Hu B, Rao MJ, Deng X, Pandey SS, Hendrich C, Ding F, Wang N, Xu Q. Molecular signatures between citrus and Candidatus Liberibacter asiaticus. PLoS Pathog 2021; 17:e1010071. [PMID: 34882744 PMCID: PMC8659345 DOI: 10.1371/journal.ppat.1010071] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Citrus Huanglongbing (HLB), also known as citrus greening, is one of the most devastating citrus diseases worldwide. Candidatus Liberibacter asiaticus (CLas) is the most prevalent strain associated with HLB, which is yet to be cultured in vitro. None of the commercial citrus cultivars are resistant to HLB. The pathosystem of Ca. Liberibacter is complex and remains a mystery. In this review, we focus on the recent progress in genomic research on the pathogen, the interaction of host and CLas, and the influence of CLas infection on the transcripts, proteins, and metabolism of the host. We have also focused on the identification of candidate genes for CLas pathogenicity or the improvements of HLB tolerance in citrus. In the end, we propose potentially promising areas for mechanistic studies of CLas pathogenicity, defense regulators, and genetic improvement for HLB tolerance/resistance in the future.
Collapse
Affiliation(s)
- Bin Hu
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (Ministry of Agriculture), Huazhong Agricultural University, Wuhan, Hubei, China
| | - Muhammad Junaid Rao
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (Ministry of Agriculture), Huazhong Agricultural University, Wuhan, Hubei, China
| | - Xiuxin Deng
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (Ministry of Agriculture), Huazhong Agricultural University, Wuhan, Hubei, China
| | - Sheo Shankar Pandey
- Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Lake Alfred, Florida, United States of America
| | - Connor Hendrich
- Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Lake Alfred, Florida, United States of America
| | - Fang Ding
- Hubei Key Laboratory of Plant Pathology, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Nian Wang
- Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Lake Alfred, Florida, United States of America
| | - Qiang Xu
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (Ministry of Agriculture), Huazhong Agricultural University, Wuhan, Hubei, China
| |
Collapse
|
23
|
Identification of citrus greening based on visual symptoms: A grower's diagnostic toolkit. Heliyon 2021; 7:e08387. [PMID: 34841106 PMCID: PMC8605348 DOI: 10.1016/j.heliyon.2021.e08387] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2021] [Revised: 11/01/2021] [Accepted: 11/11/2021] [Indexed: 11/23/2022] Open
Abstract
Citrus greening is one of the world's most serious diseases of citrus that affects all cultivars and causes the systematic death of trees worldwide. The disease is caused mostly by the bacteria Candidatus Liberibacter species. The wind, rain, and touch of infected workers cannot transmit this infectious disease. The Asian Citrus Psyllid (ACP), a minuscule insect, is one of the main vectors that transmit the disease by feeding on citrus leaves. Citrus greening management is also quite expensive since no successful treatment for the cure has been found, except to remove all affected vegetables from healthy crops to eliminate the bacterial spread. Citrus greening is also the most challenging task, as signs of other citrus diseases and nutritional deficiencies are identical. The major signs of this disease are asymmetrical, blotchy mottling patterns on leaves. Here, several visible indications of citrus greening were addressed, which will enable farmers at the root level to detect and avoid this condition prior to its having a dramatic influence on citrus plantations. We also talked about the pen test method to determine symptoms as symmetrical or asymmetrical throughout the mid-vine, regardless of whether they are impacted by citrus greening or lack of nutrients.
Collapse
|
24
|
Lally RD, Donaleshen K, Chirwa U, Eastridge K, Saintilnord W, Dickinson E, Murphy R, Borst S, Horgan K, Dawson K. Transcriptomic Response of Huanglongbing-Infected Citrus sinensis Following Field Application of a Microbial Fermentation Product. FRONTIERS IN PLANT SCIENCE 2021; 12:754391. [PMID: 34917102 PMCID: PMC8669595 DOI: 10.3389/fpls.2021.754391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 11/05/2021] [Indexed: 06/14/2023]
Abstract
Huanglongbing (HLB) is considered the most destructive disease in Citrus production and threatens the future of the industry. Microbial-derived defense elicitors have gained recognition for their role in plant defense priming. This work assessed a 5% (V/V) microbial fermentation application (MFA) and its role in the elicitation of defense responses in HLB-infected Citrus sinensis trees following a foliar application with a pump sprayer. Using a PCR detection method, HLB infection levels were monitored in healthy and infected trees for 20months. Nutrient analysis assessed N, P, K, Ca, Mg, Mn, Zn, Fe, B, and Cu concentrations in the trees. MFA significantly increased Cu concentrations in treated trees and resulted in the stabilization of disease index (DI) in infected trees. Initial real-time qPCR analysis of defense-associated genes showed a significant increase in pathogenesis-related protein 2 (PR2) and phenylalanine ammonia lyase (PAL) gene expression in healthy and HLB-infected trees in response to MFA. Gene expression of PR2 and PAL peaked 6h post-microbial fermentation application during an 8-h sampling period. A transcriptomic assessment using GeneChip microarray of the hour 6 samples revealed differential expression of 565 genes when MFA was applied to healthy trees and 909 genes when applied infected citrus trees when compared to their respective controls. There were 403 uniquely differentially expressed genes in response to MFA following an intersectional analysis of both healthy and infected citrus trees. The transcriptomic analysis revealed that several genes associated with plant development, growth, and defense were upregulated in response to MFA, including multiple PR genes, lignin formation genes, ROS-related genes, hormone synthases, and hormone regulators. This study provides further evidence that MFA may play an important role as a plant elicitor in an integrated pest management strategy in citrus and other agronomically important crops.
Collapse
Affiliation(s)
| | | | | | | | - Wesley Saintilnord
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY, United States
| | | | | | | | | | | |
Collapse
|
25
|
Li X, Ruan H, Zhou C, Meng X, Chen W. Controlling Citrus Huanglongbing: Green Sustainable Development Route Is the Future. FRONTIERS IN PLANT SCIENCE 2021; 12:760481. [PMID: 34868155 PMCID: PMC8636133 DOI: 10.3389/fpls.2021.760481] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 10/06/2021] [Indexed: 05/12/2023]
Abstract
Huanglongbing (HLB) is the most severe bacterial disease of citrus crops caused by Candidatus Liberibacter spp. It causes a reduction in fruit yield, poor fruit quality, and even plants death. Due to the lack of effective medicine, HLB is also called citrus "AIDS." Currently, it is essential for the prevention and control of HLB to use antibiotics and pesticides while reducing the spread of HLB by cultivating pathogen-free seedlings, removing disease trees, and killing Asian citrus psyllid (ACP). New compounds [e.g., antimicrobial peptides (AMPs) and nanoemulsions] with higher effectiveness and less toxicity were also found and they have made significant achievements. However, further evaluation is required before these new antimicrobial agents can be used commercially. In this review, we mainly introduced the current strategies from the aspects of physical, chemical, and biological and discussed their environmental impacts. We also proposed a green and ecological strategy for controlling HLB basing on the existing methods and previous research results.
Collapse
Affiliation(s)
- Xue Li
- MOE Key Laboratory of Laser Life Science, Institute of Laser Life Science, Guangzhou, China
- Guangdong Provincial Key Laboratory of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou, China
| | - Huaqin Ruan
- State Key Laboratory of Biocontrol and Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Chengqian Zhou
- Neuroscience Laboratory, Hugo Moser Research Institute at Kennedy Krieger, Baltimore, MD, United States
| | - Xiangchun Meng
- Key Laboratory of South Subtropical Fruit Biology and Genetic Resource Utilization (MOA), Guangzhou, China
- Key Laboratory of Tropical and Subtropical Fruit Tree Research, Guangzhou, China
- Institute of Fruit Tree Research, Guangdong Academy of Agricultural Science, Guangzhou, China
| | - Wenli Chen
- MOE Key Laboratory of Laser Life Science, Institute of Laser Life Science, Guangzhou, China
- Guangdong Provincial Key Laboratory of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou, China
| |
Collapse
|
26
|
Wang J, Haapalainen M, Nissinen AI, Pirhonen M. Dual Transcriptional Profiling of Carrot and ' Candidatus Liberibacter solanacearum' at Different Stages of Infection Suggests Complex Host-Pathogen Interaction. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2021; 34:1281-1297. [PMID: 34319773 DOI: 10.1094/mpmi-10-20-0274-r] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The interactions between the phloem-limited pathogen 'Candidatus Liberibacter solanacearum' haplotype C and carrot (Daucus carota subsp. sativus) were studied at 4, 5, and 9 weeks postinoculation (wpi), by combining dual RNA-Seq results with data on bacterial colonization and observations of the plant phenotype. In the infected plants, genes involved in jasmonate biosynthesis, salicylate signaling, pathogen-associated molecular pattern- and effector-triggered immunity, and production of pathogenesis-related proteins were up-regulated. At 4 wpi, terpenoid synthesis-related genes were up-regulated, presumably as a response to the psyllid feeding, whereas at 5 and 9 wpi, genes involved in both the terpenoid and flavonoid production were down-regulated and phenylpropanoid genes were up-regulated. Chloroplast-related gene expression was down-regulated, in concordance with the observed yellowing of the infected plant leaves. Both the RNA-Seq data and electron microscopy suggested callose accumulation in the infected phloem vessels, likely to impair the transport of photosynthates, while phloem regeneration was suggested by the formation of new sieve cells and the upregulation of cell wall-related gene expression. The 'Ca. L. solanacearum' genes involved in replication, transcription, and translation were expressed at high levels at 4 and 5 wpi, whereas, at 9 wpi, the Flp pilus genes were highly expressed, suggesting adherence and reduced mobility of the bacteria. The 'Ca. L. solanacearum' genes encoding ATP and C4-dicarboxylate uptake were differentially expressed between the early and late infection stages, suggesting a change in the dependence on different host-derived energy sources. HPE1 effector and salicylate hydroxylase were expressed, presumably to suppress host cell death and salicylic acid-dependent defenses during the infection.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
Collapse
Affiliation(s)
- Jinhui Wang
- University of Helsinki, Department of Agricultural Sciences, P. O. Box 27, FI-00014 University of Helsinki, Finland
| | - Minna Haapalainen
- University of Helsinki, Department of Agricultural Sciences, P. O. Box 27, FI-00014 University of Helsinki, Finland
| | - Anne I Nissinen
- Natural Resources Institute Finland (Luke), Natural Resources, Tietotie 2C, FI-31600 Jokioinen, Finland
| | - Minna Pirhonen
- University of Helsinki, Department of Agricultural Sciences, P. O. Box 27, FI-00014 University of Helsinki, Finland
| |
Collapse
|
27
|
Bauters L, Stojilković B, Gheysen G. Pathogens pulling the strings: Effectors manipulating salicylic acid and phenylpropanoid biosynthesis in plants. MOLECULAR PLANT PATHOLOGY 2021; 22:1436-1448. [PMID: 34414650 PMCID: PMC8518561 DOI: 10.1111/mpp.13123] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 07/15/2021] [Accepted: 08/01/2021] [Indexed: 06/01/2023]
Abstract
During evolution, plants have developed sophisticated ways to cope with different biotic and abiotic stresses. Phytohormones and secondary metabolites are known to play pivotal roles in defence responses against invading pathogens. One of the key hormones involved in plant immunity is salicylic acid (SA), of which the role in plant defence is well established and documented. Plants produce an array of secondary metabolites categorized in different classes, with the phenylpropanoids as major players in plant immunity. Both SA and phenylpropanoids are needed for an effective immune response by the plant. To successfully infect the host, pathogens secrete proteins, called effectors, into the plant tissue to lower defence. Secreted effectors can interfere with several metabolic or signalling pathways in the host to facilitate infection. In this review, we will focus on the different strategies pathogens have developed to affect the levels of SA and phenylpropanoids to increase plant susceptibility.
Collapse
Affiliation(s)
- Lander Bauters
- Department of BiotechnologyFaculty of Bioscience EngineeringGhent UniversityGhentBelgium
| | - Boris Stojilković
- Department of BiotechnologyFaculty of Bioscience EngineeringGhent UniversityGhentBelgium
| | - Godelieve Gheysen
- Department of BiotechnologyFaculty of Bioscience EngineeringGhent UniversityGhentBelgium
| |
Collapse
|
28
|
Yuan X, Chen C, Bassanezi RB, Wu F, Feng Z, Shi D, Li J, Du Y, Zhong L, Zhong B, Lu Z, Song X, Hu Y, Ouyang Z, Liu X, Xie J, Rao X, Wang X, Wu DO, Guan Z, Wang N. Region-Wide Comprehensive Implementation of Roguing Infected Trees, Tree Replacement, and Insecticide Applications Successfully Controls Citrus Huanglongbing. PHYTOPATHOLOGY 2021; 111:1361-1368. [PMID: 33356429 DOI: 10.1094/phyto-09-20-0436-r] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Huanglongbing (HLB) is a devastating citrus disease worldwide. A three-pronged approach to controlling HLB has been suggested, namely, removal of HLB-symptomatic trees, psyllid control, and replacement with HLB-free trees. However, such a strategy did not lead to successful HLB control in many citrus-producing regions, such as Florida. We hypothesize that this is because of the small-scale or incomprehensive implementation of the program; conversely, a comprehensive implementation of such a strategy at the regional level can successfully control HLB. To test our hypothesis, we investigated the effects of region-wide comprehensive implementation of this scheme to control HLB in Gannan region, China, with a total planted citrus acreage of over 110,000 ha from 2013 to 2019. With the region-wide implementation of comprehensive HLB management, the overall HLB incidence in Gannan decreased from 19.71% in 2014 to 3.86% in 2019. A partial implementation of such a program (without a comprehensive inoculum removal) at the regional level in Brazil resulted in HLB incidence increasing from 1.89% in 2010 to 19.02% in 2019. Using dynamic regression model analyses with data from both Brazil and China, we constructed a model to predict HLB incidence when all three components were applied at 100%. It was predicated that in a region-wide comprehensive implementation of such a program, HLB incidence would be controlled to a level of less than 1%. We conducted economic feasibility analyses and showed that average net profits were positive for groves that implemented the comprehensive strategy, but groves that did not implement it had negative net profits over a 10-year period. Overall, the key for the three-pronged program to successfully control HLB is the large scale (region-wide) and comprehensiveness in implementation. This study provides valuable information to control HLB and other economically important endemic diseases worldwide.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
Collapse
Affiliation(s)
- Xiaoyong Yuan
- Citrus Huanglongbing Joint Laboratory, National Navel Orange Engineering Research Center, Gannan Normal University, Ganzhou, Jiangxi, China
| | - Cixiang Chen
- Ganzhou Plant Protection Department of Fruit Industry/Jiangxi Navel Orange Engineering Research Center, Ganzhou, Jiangxi, China
| | | | - Feng Wu
- Gulf Coast Research and Education Center, University of Florida, Wimauma, FL, U.S.A
| | - Zheng Feng
- Department of Electrical & Computer Engineering, University of Florida, Gainesville, FL, U.S.A
| | - Damin Shi
- Citrus Huanglongbing Joint Laboratory, National Navel Orange Engineering Research Center, Gannan Normal University, Ganzhou, Jiangxi, China
| | - Jinyun Li
- Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Lake Alfred, FL, U.S.A
| | - Yimin Du
- Citrus Huanglongbing Joint Laboratory, National Navel Orange Engineering Research Center, Gannan Normal University, Ganzhou, Jiangxi, China
| | - Ling Zhong
- Plant Protection Bureau, Department of Agriculture, Nanchang, Jiangxi, China
| | - Balian Zhong
- National Navel Orange Engineering Research Center, Gannan Normal University, Ganzhou, Jiangxi, China
| | - Zhanjun Lu
- National Navel Orange Engineering Research Center, Gannan Normal University, Ganzhou, Jiangxi, China
| | - Xiang Song
- Citrus Huanglongbing Joint Laboratory, National Navel Orange Engineering Research Center, Gannan Normal University, Ganzhou, Jiangxi, China
| | - Yan Hu
- Ganzhou Plant Protection Department of Fruit Industry/Jiangxi Navel Orange Engineering Research Center, Ganzhou, Jiangxi, China
| | - Zhigang Ouyang
- Citrus Huanglongbing Joint Laboratory, National Navel Orange Engineering Research Center, Gannan Normal University, Ganzhou, Jiangxi, China
| | - Xinjun Liu
- Citrus Huanglongbing Joint Laboratory, National Navel Orange Engineering Research Center, Gannan Normal University, Ganzhou, Jiangxi, China
| | - Jinzhao Xie
- Ganzhou Plant Protection Department of Fruit Industry/Jiangxi Navel Orange Engineering Research Center, Ganzhou, Jiangxi, China
| | - Xi Rao
- Plant Protection Bureau, Department of Agriculture, Nanchang, Jiangxi, China
| | - Xi Wang
- Plant Protection Bureau, Department of Agriculture, Nanchang, Jiangxi, China
| | - Dapeng Oliver Wu
- Department of Electrical & Computer Engineering, University of Florida, Gainesville, FL, U.S.A
| | - Zhengfei Guan
- Gulf Coast Research and Education Center, University of Florida, Wimauma, FL, U.S.A
| | - Nian Wang
- Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Lake Alfred, FL, U.S.A
| |
Collapse
|
29
|
Darolt JC, Bento FDMM, Merlin BL, Peña L, Cônsoli FL, Wulff NA. The Genome of " Candidatus Liberibacter asiaticus" Is Highly Transcribed When Infecting the Gut of Diaphorina citri. Front Microbiol 2021; 12:687725. [PMID: 34322103 PMCID: PMC8312247 DOI: 10.3389/fmicb.2021.687725] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 06/04/2021] [Indexed: 11/13/2022] Open
Abstract
The Asian citrus psyllid, Diaphorina citri, is the vector of the bacterium "Candidatus Liberibacter asiaticus" (Las), associated with the devastating, worldwide citrus disease huanglongbing. In order to explore the molecular interactions of this bacterium with D. citri during the vector acquisition process, cDNA libraries were sequenced on an Illumina platform, obtained from the gut of adult psyllids confined in healthy (H) and in Las-infected young shoots (Las) for different periods of times (I = 1/2 days, II = 3/4 days, and III = 5/6 days). In each sampling time, three biological replicates were collected, containing 100 guts each, totaling 18 libraries depleted in ribosomal RNA. Reads were quality-filtered and mapped against the Chinese JXGC Las strain and the Floridian strain UF506 for the analysis of the activity of Las genome and SC1, SC2, and type 3 (P-JXGC-3) prophages of the studied Las strain. Gene activity was considered only if reads of at least two replicates for each acquisition access period mapped against the selected genomes, which resulted in coverages of 44.4, 79.9, and 94.5% of the JXGC predicted coding sequences in Las I, Las II, and Las III, respectively. These genes indicate an active metabolism and increased expression according to the feeding time in the following functional categories: energy production, amino acid metabolism, signal translation, cell wall, and replication and repair of genetic material. Pilins were among the most highly expressed genes regardless of the acquisition time, while only a few genes from cluster I of flagella were not expressed. Furthermore, the prophage region had a greater coverage of reads for SC1 and P-JXGC-3 prophages and low coverage in SC2 and no indication of activity for the lysis cycle. This research presents the first descriptive analysis of Las transcriptome in the initial steps of the D. citri gut colonization, where 95% of Las genes were active.
Collapse
Affiliation(s)
- Josiane Cecília Darolt
- Instituto de Química, Universidade Estadual Paulista “Julio de Mesquita Filho” – UNESP, Araraquara, Brazil
- Departamento de Pesquisa & Desenvolvimento, Fundo de Defesa da Citricultura – Fundecitrus, Araraquara, Brazil
| | - Flavia de Moura Manoel Bento
- Laboratório de Interações em Insetos, Departamento de Entomologia e Acarologia, Escola Superior de Agricultura Luiz de Queiroz, Universidade de São Paulo, Piracicaba, Brazil
| | - Bruna Laís Merlin
- Laboratório de Interações em Insetos, Departamento de Entomologia e Acarologia, Escola Superior de Agricultura Luiz de Queiroz, Universidade de São Paulo, Piracicaba, Brazil
| | - Leandro Peña
- Departamento de Pesquisa & Desenvolvimento, Fundo de Defesa da Citricultura – Fundecitrus, Araraquara, Brazil
- Instituto de Biologia Molecular y Celular de Plantas – Consejo Superior de Investigaciones Científicas, Universidade Politécnica de Valencia, Valencia, Spain
| | - Fernando Luis Cônsoli
- Laboratório de Interações em Insetos, Departamento de Entomologia e Acarologia, Escola Superior de Agricultura Luiz de Queiroz, Universidade de São Paulo, Piracicaba, Brazil
| | - Nelson Arno Wulff
- Instituto de Química, Universidade Estadual Paulista “Julio de Mesquita Filho” – UNESP, Araraquara, Brazil
- Departamento de Pesquisa & Desenvolvimento, Fundo de Defesa da Citricultura – Fundecitrus, Araraquara, Brazil
| |
Collapse
|
30
|
Li J, Kolbasov VG, Lee D, Pang Z, Huang Y, Collins N, Wang N. Residue Dynamics of Streptomycin in Citrus Delivered by Foliar Spray and Trunk Injection and Effect on ' Candidatus Liberibacter asiaticus' Titer. PHYTOPATHOLOGY 2021; 111:1095-1103. [PMID: 33267628 DOI: 10.1094/phyto-09-20-0427-r] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Streptomycin (STR) has been used to control citrus huanglongbing (HLB) caused by 'Candidatus Liberibacter asiaticus' (CLas) via foliar spray. Here, we studied the residue dynamics of STR and its effect on CLas titers in planta applied by foliar spray and trunk injection of 3-year-old citrus trees that were naturally infected by CLas in the field. After foliar spray, STR levels in leaves peaked at 2 to 7 days postapplication (dpa) and gradually declined thereafter. The STR spray did not significantly affect CLas titers in leaves of treated plants as determined by quantitative PCR. After trunk injection, peak levels of STR were observed 7 to 14 dpa in the leaf and root tissues, and near-peak levels were sustained for another 14 days before significantly declining. At 12 months after injection, moderate to low or undetectable levels of STR were observed in the leaf, root, and fruit, depending on the doses of STR injected, with a residue level of 0.28 µg/g in harvested fruit at the highest injection concentration of 2.0 µg/tree. CLas titers in leaves were significantly reduced by trunk injection of STR at 1.0 or 2.0 g/tree, starting from 7 dpa and throughout the experimental period. The reduction of CLas titers was positively correlated with STR residue levels in leaves. The in planta minimum effective concentration of STR needed to suppress the CLas titer to an undetectable level (cycle threshold ≥36.0) was 1.92 µg/g fresh weight. Determination of the in planta minimum effective concentration of STR against CLas and its spatiotemporal residue levels in planta provides the guidance to use STR for HLB management.
Collapse
Affiliation(s)
- Jinyun Li
- Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Lake Alfred, FL 33850
| | - Vladimir G Kolbasov
- Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Lake Alfred, FL 33850
| | - Donghwan Lee
- Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Lake Alfred, FL 33850
| | - Zhiqian Pang
- Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Lake Alfred, FL 33850
| | - Yixiao Huang
- Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Lake Alfred, FL 33850
| | - Nicole Collins
- Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Lake Alfred, FL 33850
| | - Nian Wang
- Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Lake Alfred, FL 33850
| |
Collapse
|
31
|
Vasconcelos FNC, Li J, Pang Z, Vincent C, Wang N. The Total Population Size of ' Candidatus Liberibacter asiaticus' Inside the Phloem of Citrus Trees and the Corresponding Metabolic Burden Related to Huanglongbing Disease Development. PHYTOPATHOLOGY 2021; 111:1122-1128. [PMID: 33090080 DOI: 10.1094/phyto-09-20-0388-r] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
'Candidatus Liberibacter asiaticus' (CLas) is the predominant causal agent of citrus huanglongbing, the most devastating citrus disease worldwide. CLas colonizes phloem tissue and causes phloem dysfunction. The pathogen population size in local tissues and in the whole plant is critical for the development of disease symptoms by determining the load of pathogenicity factors and metabolic burden to the host. However, the total population size of CLas in a whole plant and the ratio of CLas to citrus cells in local tissues have not been addressed previously. The total CLas population size for 2.5-year-old 'Valencia' sweet orange on 'Kuharske' citrange rootstock trees was quantified using quantitative PCR to be approximately 1.74 × 109 cells/tree, whereas 7- and 20-year-old sweet orange trees were estimated to be 4.3 × 1010 cells/tree, and 6.0 × 1010 cells/tree, respectively. The majority of CLas cells were distributed in leaf tissues (55.58%), followed by those in branch (36.78%), feeder root (4.75%), trunk (2.39%), and structural root (0.51%) tissues. The ratios of citrus cells to CLas cells for branch, leaf, trunk, feeder root, and structural root samples were within approximately 39 to 79, 44 to 124, 153 to 1,355, 191 to 1,054, and 561 to 3,760, respectively, representing the metabolic burden of CLas in different organs. It was estimated that the ratios of phloem cells to CLas cells for branch, leaf, trunk, feeder root, and structural root samples are approximately 0.39 to 0.79, 0.44 to 1.24, 1.53 to 13.55, 1.91 to 10.54, and 5.61 to 37.60, respectively. Approximately 0.01% of the total citrus phloem volume was estimated to be occupied by CLas, explaining the difficulty to observe CLas in most tissues under transmission electron microscopy. The CLas titer inside the leaf was estimated to be approximately 1.64 × 106 cells/leaf or 9.2 × 104 cells cm-2 in leaves, approximately 104 times less than that of typical apoplastic bacterial pathogens. This study provides quantitative estimates of phloem colonization by bacterial pathogens and furthers the understanding of the biology and virulence mechanisms of CLas.
Collapse
Affiliation(s)
- Fernanda N C Vasconcelos
- Citrus Research and Education Center (CREC), Department of Microbiology and Cell Science, University of Florida, Lake Alfred, FL 33850
| | - Jinuyn Li
- Citrus Research and Education Center (CREC), Department of Microbiology and Cell Science, University of Florida, Lake Alfred, FL 33850
| | - Zhiqian Pang
- Citrus Research and Education Center (CREC), Department of Microbiology and Cell Science, University of Florida, Lake Alfred, FL 33850
| | - Christopher Vincent
- Citrus Research and Education Center (CREC), Department of Horticultural Sciences, University of Florida, Lake Alfred, FL 33850
| | - Nian Wang
- Citrus Research and Education Center (CREC), Department of Microbiology and Cell Science, University of Florida, Lake Alfred, FL 33850
| |
Collapse
|
32
|
Alves MN, Cifuentes-Arenas JC, Raiol-Junior LL, Ferro JA, Peña L. Early Population Dynamics of " Candidatus Liberibacter asiaticus" in Susceptible and Resistant Genotypes After Inoculation With Infected Diaphorina citri Feeding on Young Shoots. Front Microbiol 2021; 12:683923. [PMID: 34177870 PMCID: PMC8219961 DOI: 10.3389/fmicb.2021.683923] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Accepted: 04/29/2021] [Indexed: 11/14/2022] Open
Abstract
Huanglongbing is a highly destructive citrus disease associated with “Candidatus Liberibacter asiaticus” (Las), a phloem−limited and non-culturable bacterium, naturally transmitted by the psyllid Diaphorina citri. Although diverse approaches have been used to understand the molecular mechanisms involved in the pathogen–host interaction, such approaches have focused on already infected and/or symptomatic plants, missing early events in the initial days post-inoculation. This study aimed to identify the time course of Las multiplication and whole-plant colonization immediately following inoculation by infected psyllids feeding for 2 days. Thus, the experimental approach was to track Las titers after psyllid inoculation in new shoots (NS) of Citrus × sinensis (susceptible), Murraya paniculata (partially resistant), and Bergera koenigii (fully resistant). Soon after psyllid removal, Las titers dropped until the 10–12th days in all three species. Following this, Las titers increased exponentially only in C. × sinensis and M. paniculata, indicating active bacterial multiplication. In C. × sinensis, Las reached a stationary phase at ∼5 log Las cells/g of tissue from the 40th day onward, while in M. paniculata, Las increased at a lower rate of up to ∼3 log Las cells/g of tissue between the 40th and 60th days, decreasing gradually thereafter and becoming undetectable from the 160th day onward. In B. koenigii, Las titers decreased from the start and remained undetectable. In C. × sinensis, an average of 2.6 log of Las cells/g of tissue was necessary for Las to move out of 50% of the NS in 23.6 days and to colonize the rest of the plant, causing a successful infection. Conversely, the probability of Las moving out of the NS remained below 50% in M. paniculata and zero in B. koenigii. To our knowledge, this is the first study on Las dynamics and whole-plant colonization during the earliest stages of infection. Identification of critical time-points for either successful multiplication or Las resistance may help to elucidate initial events of Las–host interactions that may be missed due to longer sampling intervals and at later stages of infection.
Collapse
Affiliation(s)
- Mônica Neli Alves
- Faculdade de Ciências Agrárias e Veterinárias (FCAV), Universidade Estadual Paulista (UNESP), Jaboticabal, Brazil.,Fundo de Defesa da Citricultura (Fundecitrus), Araraquara, Brazil
| | | | | | - Jesus Aparecido Ferro
- Faculdade de Ciências Agrárias e Veterinárias (FCAV), Universidade Estadual Paulista (UNESP), Jaboticabal, Brazil
| | - Leandro Peña
- Fundo de Defesa da Citricultura (Fundecitrus), Araraquara, Brazil.,Instituto de Biología Molecular y Celular de Plantas (IBMCP), Consejo Superior de Investigaciones Científicas (CSIC), Universidad Politécnica de Valencia (UPV), Valencia, Spain
| |
Collapse
|
33
|
Pandey SS, Nogales da Costa Vasconcelos F, Wang N. Spatiotemporal Dynamics of ' Candidatus Liberibacter asiaticus' Colonization Inside Citrus Plant and Huanglongbing Disease Development. PHYTOPATHOLOGY 2021; 111:921-928. [PMID: 33174821 DOI: 10.1094/phyto-09-20-0407-r] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
'Candidatus Liberibacter asiaticus' (CLas), the causal agent of citrus huanglongbing (HLB), colonizes inside the phloem and is naturally transmitted by the Asian citrus psyllid (ACP). Here, we investigated spatiotemporal CLas colonization in different tissues after ACP transmission. Of the nine plants successfully infected via ACP transmission, CLas was detected in the roots of all trees at 75 days postremoval of ACPs (DPR) but in the mature leaf of only one tree; this finding is consistent with the model that CLas moves passively from source to sink tissues. At 75 and 365 DPR, CLas was detected in 11.1 and 43.1% of mature leaves not fed on by ACPs during transmission, respectively, unveiling active movement to the source tissue. The difference in colonization timing of sink and source tissues indicates that CLas is capable of both passive and active movement, with passive movement being dominant. At 225 DPR, leaves fed on by ACPs during the young stage showed the highest ratio of HLB symptomatic leaves and the highest CLas titer, followed by leaves that emerged after ACP removal and mature leaves not fed on by ACPs. Importantly, our data showed that ACPs were unable to transmit CLas via feeding on mature leaves. It is estimated that it takes 3 years at most for CLas to infect the whole tree. Overall, spatiotemporal detection of CLas in different tissues after ACP transmission helps visualize the infection process of CLas in planta and subsequent HLB symptom development and provides evidence showing that young leaves should be the focus of HLB management.
Collapse
Affiliation(s)
- Sheo Shankar Pandey
- Citrus Research and Education Center, Department of Microbiology and Cell Science, University of Florida, Lake Alfred, FL 33850
| | | | - Nian Wang
- Citrus Research and Education Center, Department of Microbiology and Cell Science, University of Florida, Lake Alfred, FL 33850
| |
Collapse
|
34
|
Li B, Zhang Y, Qiu D, Francis F, Wang S. Comparative Proteomic Analysis of Sweet Orange Petiole Provides Insights Into the Development of Huanglongbing Symptoms. FRONTIERS IN PLANT SCIENCE 2021; 12:656997. [PMID: 33953735 PMCID: PMC8092123 DOI: 10.3389/fpls.2021.656997] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 03/10/2021] [Indexed: 06/12/2023]
Abstract
Huanglongbing (HLB) is the most destructive citrus disease worldwide. This is associated with the phloem-limited bacterium Candidatus Liberibacter, and the typical symptom is leaf blotchy mottle. To better understand the biological processes involved in the establishment of HLB disease symptoms, the comparative proteomic analysis was performed to reveal the global protein accumulation profiles in leaf petiole, where there are massive HLB pathogens of Ca. L. asiaticus-infected Newhall sweet orange (Citrus sinensis) plants at the asymptomatic and symptomatic stages compared to their healthy counterpart. Photosynthesis, especially the pathway involved in the photosystem I and II light reactions, was shown to be suppressed throughout the whole Ca. L. asiaticus infection cycle. Also, starch biosynthesis was induced after the symptom-free prodromal period. Many defense-associated proteins were more extensively regulated in the petiole with the symptoms than the ones from healthy plants. The change of salicylic and jasmonic acid levels in different disease stages had a positive correlation with the abundance of phytohormone biosynthesis-related proteins. Moreover, the protein-protein interaction network analysis indicated that an F-type ATPase and an alpha-1,4 glucan phosphorylase were the core nodes in the interactions of differentially accumulated proteins. Our study indicated that the infected citrus plants probably activated the non-unified and lagging enhancement of defense responses against Ca. L. asiaticus at the expense of photosynthesis and contribute to find out the key Ca. L. asiaticus-responsive genes for tolerance and resistance breeding.
Collapse
Affiliation(s)
- Bo Li
- The State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
- Functional and Evolutionary Entomology, Gembloux Agro-Bio Tech, University of Liège, Gembloux, Belgium
| | - Yi Zhang
- The State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Dewen Qiu
- The State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Frédéric Francis
- Functional and Evolutionary Entomology, Gembloux Agro-Bio Tech, University of Liège, Gembloux, Belgium
| | - Shuangchao Wang
- The State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| |
Collapse
|
35
|
" Candidatus Liberibacter asiaticus" Secretes Nonclassically Secreted Proteins That Suppress Host Hypersensitive Cell Death and Induce Expression of Plant Pathogenesis-Related Proteins. Appl Environ Microbiol 2021; 87:AEM.00019-21. [PMID: 33579681 PMCID: PMC8091116 DOI: 10.1128/aem.00019-21] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Although emerging evidence indicates that bacteria extracellularly export many cytoplasmic proteins referred to as non-classically secreted proteins (ncSecPs) for their own benefit, the mechanisms and functional significance of the ncSecPs in extracellular milieu remain elusive. "Candidatus Liberibacter asiaticus" (CLas) is a fastidious Gram-negative bacterium that causes Huanglongbing (HLB), the most globally devastating citrus disease. In this study, using the SecretomeP program coupled with an Escherichia coli alkaline phosphatase assay, we identified 27 ncSecPs from the CLas genome. Further, we demonstrated that 10 of these exhibited significantly higher levels of gene expression in citrus than in psyllid hosts, and particularly suppressed hypersensitive response (HR)-based cell death and H2O2 overaccumulation in Nicotiana benthamiana, indicating their opposing effects on early plant defenses. However, these proteins also dramatically enhanced the gene expression of pathogenesis-related 1 protein (PR-1), PR-2, and PR-5, essential components of plant defense mechanisms. Additional experiments disclosed that the increased expression of these PR genes, in particular PR-1 and PR-5, could negatively regulate HR-based cell death development and H2O2 accumulation. Remarkably, CLas infection clearly induced gene expression of PR-1, PR-2, and PR-5 in both HLB-tolerant and HLB-susceptible species of citrus plants. Taken together, we hypothesized that CLas has evolved an arsenal of ncSecPs that function cooperatively to overwhelm the early plant defenses by inducing host PR genes.IMPORTANCE In this study, we present a combined computational and experimental methodology that allows a rapid and efficient identification of the ncSecPs from bacteria, in particular the unculturable bacteria like CLas. Meanwhile, the study determined that a number of CLas ncSecPs suppressed HR-based cell death, and thus indicated a novel role for the bacterial ncSecPs in extracellular milieu. More importantly, these ncSecPs were found to suppress cell death presumably by utilizing host PR proteins. The data overall provide a novel clue to understand the CLas pathogenesis and also suggest a new way by which phytopathogens manipulate host cellular machinery to establish infection.
Collapse
|
36
|
Zou X, Zhao K, Liu Y, Du M, Zheng L, Wang S, Xu L, Peng A, He Y, Long Q, Chen S. Overexpression of Salicylic Acid Carboxyl Methyltransferase ( CsSAMT1) Enhances Tolerance to Huanglongbing Disease in Wanjincheng Orange ( Citrus sinensis (L.) Osbeck). Int J Mol Sci 2021; 22:ijms22062803. [PMID: 33802058 PMCID: PMC7999837 DOI: 10.3390/ijms22062803] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 03/05/2021] [Accepted: 03/08/2021] [Indexed: 11/30/2022] Open
Abstract
Citrus Huanglongbing (HLB) disease or citrus greening is caused by Candidatus Liberibacter asiaticus (Las) and is the most devastating disease in the global citrus industry. Salicylic acid (SA) plays a central role in regulating plant defenses against pathogenic attack. SA methyltransferase (SAMT) modulates SA homeostasis by converting SA to methyl salicylate (MeSA). Here, we report on the functions of the citrus SAMT (CsSAMT1) gene from HLB-susceptible Wanjincheng orange (Citrus sinensis (L.) Osbeck) in plant defenses against Las infection. The CsSAMT1 cDNA was expressed in yeast. Using in vitro enzyme assays, yeast expressing CsSAMT1 was confirmed to specifically catalyze the formation of MeSA using SA as a substrate. Transgenic Wanjincheng orange plants overexpressing CsSAMT1 had significantly increased levels of SA and MeSA compared to wild-type controls. HLB resistance was evaluated for two years and showed that transgenic plants displayed significantly alleviated symptoms including a lack of chlorosis, low bacterial counts, reduced hyperplasia of the phloem cells, and lower levels of starch and callose compared to wild-type plants. These data confirmed that CsSAMT1 overexpression confers an enhanced tolerance to Las in citrus fruits. RNA-seq analysis revealed that CsSAMT1 overexpression significantly upregulated the citrus defense response by enhancing the transcription of disease resistance genes. This study provides insight for improving host resistance to HLB by manipulation of SA signaling in citrus fruits.
Collapse
|
37
|
Yang F, Xiao K, Pan H, Liu J. Chloroplast: The Emerging Battlefield in Plant-Microbe Interactions. FRONTIERS IN PLANT SCIENCE 2021; 12:637853. [PMID: 33747017 PMCID: PMC7966814 DOI: 10.3389/fpls.2021.637853] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 01/28/2021] [Indexed: 05/08/2023]
Abstract
Higher plants and some algae convert the absorbed light into chemical energy through one of the most important organelles, chloroplast, for photosynthesis and store it in the form of organic compounds to supply their life activities. However, more and more studies have shown that the role of chloroplasts is more than a factory for photosynthesis. In the process of light conversion to chemical energy, any damage to the components of chloroplast may affect the photosynthesis efficiency and promote the production of by-products, reactive oxygen species, that are mainly produced in the chloroplasts. Substantial evidence show that chloroplasts are also involved in the battle of plants and microbes. Chloroplasts are important in integrating a variety of external environmental stimuli and regulate plant immune responses by transmitting signals to the nucleus and other cell compartments through retrograde signaling pathways. Besides, chloroplasts can also regulate the biosynthesis and signal transduction of phytohormones, including salicylic acid and jasmonic acid, to affect the interaction between the plants and microbes. Since chloroplasts play such an important role in plant immunity, correspondingly, chloroplasts have become the target of pathogens. Different microbial pathogens target the chloroplast and affect its functions to promote their colonization in the host plants.
Collapse
Affiliation(s)
| | | | | | - Jinliang Liu
- College of Plant Sciences, Jilin University, Changchun, China
| |
Collapse
|
38
|
Gallinger J, Zikeli K, Zimmermann MR, Görg LM, Mithöfer A, Reichelt M, Seemüller E, Gross J, Furch ACU. Specialized 16SrX phytoplasmas induce diverse morphological and physiological changes in their respective fruit crops. PLoS Pathog 2021; 17:e1009459. [PMID: 33765095 PMCID: PMC8023467 DOI: 10.1371/journal.ppat.1009459] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 04/06/2021] [Accepted: 03/07/2021] [Indexed: 11/19/2022] Open
Abstract
The host-pathogen combinations-Malus domestica (apple)/`Candidatus Phytoplasma mali´, Prunus persica (peach)/`Ca. P. prunorum´ and Pyrus communis (pear)/`Ca. P. pyri´ show different courses of diseases although the phytoplasma strains belong to the same 16SrX group. While infected apple trees can survive for decades, peach and pear trees die within weeks to few years. To this date, neither morphological nor physiological differences caused by phytoplasmas have been studied in these host plants. In this study, phytoplasma-induced morphological changes of the vascular system as well as physiological changes of the phloem sap and leaf phytohormones were analysed and compared with non-infected plants. Unlike peach and pear, infected apple trees showed substantial reductions in leaf and vascular area, affecting phloem mass flow. In contrast, in infected pear mass flow and physicochemical characteristics of phloem sap increased. Additionally, an increased callose deposition was detected in pear and peach leaves but not in apple trees in response to phytoplasma infection. The phytohormone levels in pear were not affected by an infection, while in apple and peach trees concentrations of defence- and stress-related phytohormones were increased. Compared with peach and pear trees, data from apple suggest that the long-lasting morphological adaptations in the vascular system, which likely cause reduced sap flow, triggers the ability of apple trees to survive phytoplasma infection. Some phytohormone-mediated defences might support the tolerance.
Collapse
Affiliation(s)
- Jannicke Gallinger
- Institute for Plant Protection in Fruit Crops and Viticulture, Julius Kühn-Institut, Federal Research Institute for Cultivated Plants, Dossenheim, Germany
| | - Kerstin Zikeli
- Institute for Plant Protection in Fruit Crops and Viticulture, Julius Kühn-Institut, Federal Research Institute for Cultivated Plants, Dossenheim, Germany
| | - Matthias R. Zimmermann
- Plant Physiology, Matthias-Schleiden-Institute for Genetics, Bioinformatics and Molecular Botany, Faculty of Biological Science, Friedrich-Schiller-University Jena, Jena, Germany
| | - Louisa M. Görg
- Institute for Plant Protection in Fruit Crops and Viticulture, Julius Kühn-Institut, Federal Research Institute for Cultivated Plants, Dossenheim, Germany
| | - Axel Mithöfer
- Research Group Plant Defense Physiology, Max-Planck Institute for Chemical Ecology, Jena, Germany
| | - Michael Reichelt
- Department of Biochemistry, Max-Planck Institute for Chemical Ecology, Jena, Germany
| | - Erich Seemüller
- Institute for Plant Protection in Fruit Crops and Viticulture, Julius Kühn-Institut, Federal Research Institute for Cultivated Plants, Dossenheim, Germany
| | - Jürgen Gross
- Institute for Plant Protection in Fruit Crops and Viticulture, Julius Kühn-Institut, Federal Research Institute for Cultivated Plants, Dossenheim, Germany
| | - Alexandra C. U. Furch
- Plant Physiology, Matthias-Schleiden-Institute for Genetics, Bioinformatics and Molecular Botany, Faculty of Biological Science, Friedrich-Schiller-University Jena, Jena, Germany
| |
Collapse
|
39
|
Cruzado-Gutiérrez RK, Sadeghi R, Prager SM, Casteel CL, Parker J, Wenninger EJ, Price WJ, Bosque-Pérez NA, Karasev AV, Rashed A. Interspecific interactions within a vector-borne complex are influenced by a co-occurring pathosystem. Sci Rep 2021; 11:2242. [PMID: 33500488 PMCID: PMC7838419 DOI: 10.1038/s41598-021-81710-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 01/05/2021] [Indexed: 11/25/2022] Open
Abstract
Potato virus Y (PVY) and zebra chip (ZC) disease are major threats to solanaceous crop production in North America. PVY can be spread by aphid vectors and through vegetative propagation in potatoes. ZC is associated with "Candidatus Liberibacter solanacearum" (Lso), which is transmitted by the tomato/potato psyllid, Bactericera cockerelli Šulc (Hemiptera: Triozidae). As these two pathosystems may co-occur, we studied whether the presence of one virus strain, PVY°, affected the host preference, oviposition, and egg hatch rate of Lso-free or Lso-carrying psyllids in tomato plants. We also examined whether PVY infection influenced Lso transmission success by psyllids, Lso titer and plant chemistry (amino acids, sugars, and phytohormones). Lso-carrying psyllids showed a preference toward healthy hosts, whereas the Lso-free psyllids preferentially settled on the PVY-infected tomatoes. Oviposition of the Lso-carrying psyllids was lower on PVY-infected than healthy tomatoes, but Lso transmission, titer, and psyllid egg hatch were not significantly affected by PVY. The induction of salicylic acid and its related responses, and not nutritional losses, may explain the reduced attractiveness of the PVY-infected host to the Lso-carrying psyllids. Although our study demonstrated that pre-existing PVY infection can reduce oviposition by the Lso-carrying vector, the preference of the Lso-carrying psyllids to settle on healthy hosts could contribute to Lso spread to healthy plants in the presence of PVY infection in a field.
Collapse
Affiliation(s)
- Regina K Cruzado-Gutiérrez
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Aberdeen R&E Center, Aberdeen, ID, 83210, USA
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Moscow, ID, 83844, USA
| | - Rohollah Sadeghi
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Moscow, ID, 83844, USA
| | - Sean M Prager
- Department of Plant Science, University of Saskatchewan, Saskatoon, SK, S7N 5A8, Canada
| | - Clare L Casteel
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY, 14853, USA
| | - Jessica Parker
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Moscow, ID, 83844, USA
| | - Erik J Wenninger
- Department of Entomology, Plant Pathology and Nematology, Kimberly Research & Extension Center, University of Idaho, Kimberly, ID, 83341, USA
| | - William J Price
- College of Agricultural and Life Sciences, Statistical Programs, University of Idaho, Moscow, ID, 83844, USA
| | - Nilsa A Bosque-Pérez
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Moscow, ID, 83844, USA
| | - Alexander V Karasev
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Moscow, ID, 83844, USA
| | - Arash Rashed
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Aberdeen R&E Center, Aberdeen, ID, 83210, USA.
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Moscow, ID, 83844, USA.
| |
Collapse
|
40
|
Rao MJ, Zuo H, Xu Q. Genomic insights into citrus domestication and its important agronomic traits. PLANT COMMUNICATIONS 2021; 2:100138. [PMID: 33511347 PMCID: PMC7816076 DOI: 10.1016/j.xplc.2020.100138] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 12/04/2020] [Accepted: 12/25/2020] [Indexed: 05/12/2023]
Abstract
Citrus originated in Southeast Asia, and it has become one of the most important fruit crops worldwide. Citrus has a long and obscure domestication history due to its clonal propagation, long life cycle, wide sexual compatibility, and complex genetic background. As the genomic information of both wild and cultivated citrus becomes available, their domestication history and underlying traits or genes are becoming clear. This review outlines the genomic features of wild and cultivated species. We propose that the reduction of citric acid is a critical trait for citrus domestication. The genetic model representing the change during domestication may be associated with a regulatory complex known as WD-repeat-MYB-bHLH-WRKY (WMBW), which is involved in acidification and anthocyanin accumulation. The reduction in or loss of anthocyanins may be due to a hitchhiking effect of fruit acidity selection, in which mutation occurs in the common regulator of these two pathways in some domesticated types. Moreover, we have summarized the domestication traits and candidate genes for breeding purposes. This review represents a comprehensive summary of the genes controlling key traits of interest, such as acidity, metabolism, and disease resistance. It also sheds light on recent advances in early flowering from transgenic studies and provides a new perspective for fast breeding of citrus. Our review lays a foundation for future research on fruit acidity, flavor, and disease resistance in citrus.
Collapse
Affiliation(s)
- Muhammad Junaid Rao
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops, Ministry of Agriculture, Key Laboratory of Horticultural Plant Biology (Ministry of Education) Huazhong Agricultural University, Wuhan, Hubei 430070, P.R. China
| | - Hao Zuo
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops, Ministry of Agriculture, Key Laboratory of Horticultural Plant Biology (Ministry of Education) Huazhong Agricultural University, Wuhan, Hubei 430070, P.R. China
| | - Qiang Xu
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops, Ministry of Agriculture, Key Laboratory of Horticultural Plant Biology (Ministry of Education) Huazhong Agricultural University, Wuhan, Hubei 430070, P.R. China
| |
Collapse
|
41
|
Franco JY, Thapa SP, Pang Z, Gurung FB, Liebrand TWH, Stevens DM, Ancona V, Wang N, Coaker G. Citrus Vascular Proteomics Highlights the Role of Peroxidases and Serine Proteases during Huanglongbing Disease Progression. Mol Cell Proteomics 2020; 19:1936-1952. [PMID: 32883801 PMCID: PMC7710146 DOI: 10.1074/mcp.ra120.002075] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2020] [Revised: 08/04/2020] [Indexed: 01/17/2023] Open
Abstract
Huanglongbing (HLB) is the most devastating and widespread citrus disease. All commercial citrus varieties are susceptible to the HLB-associated bacterium, Candidatus Liberibacter asiaticus (CLas), which resides in the phloem. The phloem is part of the plant vascular system and is involved in sugar transport. To investigate the plant response to CLas, we enriched for proteins surrounding the phloem in an HLB susceptible sweet orange variety, Washington navel (Citrus sinensis (L) Osbeck). Quantitative proteomics revealed global changes in the citrus proteome after CLas inoculation. Plant metabolism and translation were suppressed, whereas defense-related proteins such as peroxidases, proteases and protease inhibitors were induced in the vasculature. Transcript accumulation and enzymatic activity of plant peroxidases in CLas infected sweet orange varieties under greenhouse and field conditions were assessed. Although peroxidase transcript accumulation was induced in CLas infected sweet orange varieties, peroxidase enzymatic activity varied. Specific serine proteases were up-regulated in Washington navel in the presence of CLas based on quantitative proteomics. Subsequent activity-based protein profiling revealed increased activity of two serine proteases, and reduced activity of one protease in two C. sinensis sweet orange varieties under greenhouse and field conditions. The observations in the current study highlight global reprogramming of the citrus vascular proteome and differential regulation of enzyme classes in response to CLas infection. These results open an avenue for further investigation of diverse responses to HLB across different environmental conditions and citrus genotypes.
Collapse
Affiliation(s)
- Jessica Y Franco
- Department of Plant Pathology, University of California, Davis, California, USA
| | - Shree P Thapa
- Department of Plant Pathology, University of California, Davis, California, USA
| | - Zhiqian Pang
- Citrus Research and Education Center, University of Florida, Lake Alfred, Florida, USA
| | - Fatta B Gurung
- Citrus Center, Texas A&M University- Kingsville, Weslaco, Texas, USA
| | - Thomas W H Liebrand
- Department of Plant Pathology, University of California, Davis, California, USA
| | - Danielle M Stevens
- Department of Plant Pathology, University of California, Davis, California, USA
| | - Veronica Ancona
- Citrus Center, Texas A&M University- Kingsville, Weslaco, Texas, USA
| | - Nian Wang
- Citrus Research and Education Center, University of Florida, Lake Alfred, Florida, USA
| | - Gitta Coaker
- Department of Plant Pathology, University of California, Davis, California, USA.
| |
Collapse
|
42
|
Curtolo M, de Souza Pacheco I, Boava LP, Takita MA, Granato LM, Galdeano DM, de Souza AA, Cristofani-Yaly M, Machado MA. Wide-ranging transcriptomic analysis of Poncirus trifoliata, Citrus sunki, Citrus sinensis and contrasting hybrids reveals HLB tolerance mechanisms. Sci Rep 2020; 10:20865. [PMID: 33257732 PMCID: PMC7705011 DOI: 10.1038/s41598-020-77840-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Accepted: 10/09/2020] [Indexed: 01/04/2023] Open
Abstract
Huanglongbing (HLB), caused mainly by ‘Candidatus Liberibacter asiaticus’ (CLas), is the most devastating citrus disease because all commercial species are susceptible. HLB tolerance has been observed in Poncirus trifoliata and their hybrids. A wide-ranging transcriptomic analysis using contrasting genotypes regarding HLB severity was performed to identify the genetic mechanism associated with tolerance to HLB. The genotypes included Citrus sinensis, Citrus sunki, Poncirus trifoliata and three distinct groups of hybrids obtained from crosses between C. sunki and P. trifoliata. According to bacterial titer and symptomatology studies, the hybrids were clustered as susceptible, tolerant and resistant to HLB. In P. trifoliata and resistant hybrids, genes related to specific pathways were differentially expressed, in contrast to C. sinensis, C. sunki and susceptible hybrids, where several pathways were reprogrammed in response to CLas. Notably, a genetic tolerance mechanism was associated with the downregulation of gibberellin (GA) synthesis and the induction of cell wall strengthening. These defense mechanisms were triggered by a class of receptor-related genes and the induction of WRKY transcription factors. These results led us to build a hypothetical model to understand the genetic mechanisms involved in HLB tolerance that can be used as target guidance to develop citrus varieties or rootstocks with potential resistance to HLB.
Collapse
Affiliation(s)
- Maiara Curtolo
- Centro de Citricultura Sylvio Moreira, Instituto Agronômico de Campinas, Cordeirópolis, SP, Brazil. .,Universidade Estadual de Campinas, Campinas, SP, Brazil.
| | - Inaiara de Souza Pacheco
- Centro de Citricultura Sylvio Moreira, Instituto Agronômico de Campinas, Cordeirópolis, SP, Brazil.,Universidade Estadual de Campinas, Campinas, SP, Brazil
| | - Leonardo Pires Boava
- Centro de Citricultura Sylvio Moreira, Instituto Agronômico de Campinas, Cordeirópolis, SP, Brazil
| | - Marco Aurélio Takita
- Centro de Citricultura Sylvio Moreira, Instituto Agronômico de Campinas, Cordeirópolis, SP, Brazil
| | - Laís Moreira Granato
- Centro de Citricultura Sylvio Moreira, Instituto Agronômico de Campinas, Cordeirópolis, SP, Brazil
| | - Diogo Manzano Galdeano
- Centro de Citricultura Sylvio Moreira, Instituto Agronômico de Campinas, Cordeirópolis, SP, Brazil
| | | | | | - Marcos Antonio Machado
- Centro de Citricultura Sylvio Moreira, Instituto Agronômico de Campinas, Cordeirópolis, SP, Brazil
| |
Collapse
|
43
|
Zhang C, Du P, Yan H, Zhu Z, Wang X, Li W. A Sec-Dependent Secretory Protein of the Huanglongbing-Associated Pathogen Suppresses Hypersensitive Cell Death in Nicotiana benthamiana. Front Microbiol 2020; 11:594669. [PMID: 33329478 PMCID: PMC7734103 DOI: 10.3389/fmicb.2020.594669] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 11/04/2020] [Indexed: 11/13/2022] Open
Abstract
"Candidatus Liberibacter asiaticus" (CLas) is a phloem-restricted Gram-negative bacterium that is the causal agent of citrus huanglongbing (HLB). In this study, we identified a CLas-encoded Sec-dependent secretory protein CLIBASIA_04405 that could contribute to the pathogenicity of this bacterium. The gene expression level of CLIBASIA_04405 was significantly higher in citrus than in psyllids. Transient overexpression of the mature CLIBASIA_04405 protein (m4405) in Nicotiana benthamiana leaves could suppress hypersensitive response (HR)-based cell death and H2O2 accumulation triggered by the mouse BAX and the Phytophthora infestans INF1. An alanine-substitution mutagenesis assay revealed the essential of amino acid clusters EKR45-47 and DE64-65 in cell death suppression. Challenge inoculation of the transgenic N. benthamiana-expressing m4405 with Pseudomonas syringae DC3000ΔhopQ1-1 demonstrated the greatly reduced bacterial proliferation. Remarkably, transcriptome profiling and RT-qPCR analysis disclosed that the gene expression of six small heat shock proteins (sHSPs), a set of plant defense regulators, were significantly elevated in the transgenic m4405 lines compared with those in wild-type N. benthamiana. In addition, the transgenic m4405 lines displayed phenotypes of dwarfism and leaf deformation. Altogether, these data indicated that m4405 was a virulence factor of CLas.
Collapse
Affiliation(s)
- Chao Zhang
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Peixiu Du
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Hailin Yan
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China.,College of Plant Science, Tarim University, Alar, China
| | - Zongcai Zhu
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China.,College of Plant Science, Tarim University, Alar, China
| | - Xuefeng Wang
- Citrus Research Institute, Southwest University, Chongqing, China
| | - Weimin Li
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China
| |
Collapse
|
44
|
Gómez LM, Teixeira-Silva NS, Caserta R, Takita MA, Marques MOM, de Souza AA. Overexpression of Citrus reticulata SAMT in Nicotiana tabacum increases MeSA volatilization and decreases Xylella fastidiosa symptoms. PLANTA 2020; 252:103. [PMID: 33185761 DOI: 10.1007/s00425-020-03511-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 11/03/2020] [Indexed: 06/11/2023]
Abstract
MAIN CONCLUSION Nicotiana tabacum overexpressing CrSAMT from Citrus reticulata increased production of MeSA, which works as an airborne signal in neighboring wild-type plants, inducing PR1 and increasing resistance to the pathogen Xylella fastidiosa. Xylella fastidiosa is one of the major threats to plant health worldwide, affecting yield in many crops. Despite many efforts, the development of highly productive resistant varieties has been challenging. In studying host plant resistance, the S-adenosyl-L-methionine: salicylic acid carboxyl methyltransferase gene (SAMT) from Citrus reticulata, a X. fastidiosa resistant species, was upregulated in response to pathogen infection. SAMT is involved with the catalysis and production of methyl salicylate (MeSA), an airborne signal responsible for triggering systemic acquired resistance. Here we used tobacco as a model system and generated transgenic plants overexpressing C. reticulata SAMT (CrSAMT). We performed an in silico structural characterization of CrSAMT and investigated its biotechnological potential in modulating the immune system in transgenic plants. The increase of MeSA production in transgenic lines was confirmed by gas chromatography (GC-MS). The transgenic lines showed upregulation of PR1, and their incubation with neighboring wild-type plants activated PR1 expression, indicating that MeSA worked as an airborne signal. In addition, transgenic plants showed significantly fewer symptoms when challenged with X. fastidiosa. Altogether, these data suggest that CrSAMT plays a role in host defense response and can be used in biotechnology approaches to confer resistance against X. fastidiosa.
Collapse
Affiliation(s)
- Laura M Gómez
- Centro de Citricultura Sylvio Moreira/IAC, Rodovia Anhanguera, km 158, PO Box 04, Cordeirópolis, SP, 13490-970, Brazil
- Entomology and Plant Pathology Department, Auburn University, Auburn, AL, USA
| | - Natália S Teixeira-Silva
- Centro de Citricultura Sylvio Moreira/IAC, Rodovia Anhanguera, km 158, PO Box 04, Cordeirópolis, SP, 13490-970, Brazil
| | - Raquel Caserta
- Centro de Citricultura Sylvio Moreira/IAC, Rodovia Anhanguera, km 158, PO Box 04, Cordeirópolis, SP, 13490-970, Brazil
| | - Marco A Takita
- Centro de Citricultura Sylvio Moreira/IAC, Rodovia Anhanguera, km 158, PO Box 04, Cordeirópolis, SP, 13490-970, Brazil
| | - Márcia O M Marques
- Departamento de Fitoquímica/IAC, Avenida Doutor Theodureto Almeida Camargo 1500, Campinas, SP, 13012970, Brazil
| | - Alessandra A de Souza
- Centro de Citricultura Sylvio Moreira/IAC, Rodovia Anhanguera, km 158, PO Box 04, Cordeirópolis, SP, 13490-970, Brazil.
| |
Collapse
|
45
|
Qadri M, Short S, Gast K, Hernandez J, Wong ACN. Microbiome Innovation in Agriculture: Development of Microbial Based Tools for Insect Pest Management. FRONTIERS IN SUSTAINABLE FOOD SYSTEMS 2020. [DOI: 10.3389/fsufs.2020.547751] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
|
46
|
Heterologous Expression of the Constitutive Disease Resistance 2 and 8 Genes from Poncirus trifoliata Restored the Hypersensitive Response and Resistance of Arabidopsis cdr1 Mutant to Bacterial Pathogen Pseudomonas syringae. PLANTS 2020; 9:plants9070821. [PMID: 32629813 PMCID: PMC7412121 DOI: 10.3390/plants9070821] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 06/19/2020] [Accepted: 06/29/2020] [Indexed: 01/23/2023]
Abstract
Huanglongbing (HLB), also known as citrus greening, is the most destructive disease of citrus worldwide. In the United States, this disease is associated with a phloem-restricted bacterium, Candidatus Liberibacter asiaticus. Commercial citrus cultivars are susceptible to HLB, but Poncirus trifoliata, a close relative of Citrus, is highly tolerant of HLB. Isolating P. trifoliata gene(s) controlling its HLB tolerance followed by expressing the gene(s) in citrus is considered a potential cisgenic approach to engineering citrus for tolerance to HLB. Previous gene expression studies indicated that the constitutive disease resistance (CDR) genes in P. trifoliata (PtCDRs) may play a vital role in its HLB tolerance. This study was designed to use Arabidopsis mutants as a model system to confirm the function of PtCDRs in plant disease resistance. PtCDR2 and PtCDR8 were amplified from P. trifoliata cDNA and transferred into the Arabidopsis cdr1 mutant, whose resident CDR1 gene was disrupted by T-DNA insertion. The PtCDR2 and PtCDR8 transgenic Arabidopsis cdr1 mutant restored its hypersensitive response to the bacterial pathogen Pseudomonas syringae pv. tomato strain DC3000 (Pst DC3000) expressing avrRpt2. The defense marker gene PATHOGENESIS RELATED 1 (PR1) expressed at much higher levels in the PtCDR2 or PtCDR8 transgenic cdr1 mutant than in the non-transgenic cdr1 mutant with or without pathogen infection. Multiplication of Pst DC3000 bacteria in Arabidopsis was inhibited by the expression of PtCDR2 and PtCDR8. Our results showed that PtCDR2 and PtCDR8 were functional in Arabidopsis and played a positive role in disease resistance and demonstrated that Arabidopsis mutants can be a useful alternate system for screening Poncirus genes before making the time-consuming effort to transfer them into citrus, a perennial woody plant that is highly recalcitrant for Agrobacterium or biolistic-mediated transformation.
Collapse
|
47
|
Acid Soil Improvement Enhances Disease Tolerance in Citrus Infected by Candidatus Liberibacter asiaticus. Int J Mol Sci 2020; 21:ijms21103614. [PMID: 32443846 PMCID: PMC7279377 DOI: 10.3390/ijms21103614] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 05/13/2020] [Accepted: 05/15/2020] [Indexed: 11/20/2022] Open
Abstract
Huanglongbing (HLB) is a devastating citrus disease that has caused massive economic losses to the citrus industry worldwide. The disease is endemic in most citrus-producing areas of southern China, especially in the sweet orange orchards where soil acidification has intensified. In this work, we used lime as soil pH amendment to optimize soil pH and enhance the endurance capacity of citrus against Candidatus Liberibacter asiaticus (CLas). The results showed that regulation of soil acidity is effective to reduce the occurrence of new infections and mitigate disease severity in the presence of HLB disease. We also studied the associated molecular mechanism and found that acid soil improvement can (i) increase the root metabolic activity and up-regulate the expression of ion transporter-related genes in HLB-infected roots, (ii) alleviate the physiological disorders of sieve tube blockage of HLB-infected leaves, (iii) strengthen the citrus immune response by increasing the expression of genes involved in SAR and activating the salicylic acid signal pathway, (iv) up-regulate 55 proteins related to stress/defence response and secondary metabolism. This study contributes to a better understanding of the correlation between environment factors and HLB disease outbreaks and also suggests that acid soil improvement is of potential value for the management of HLB disease in southern China.
Collapse
|
48
|
Gardner CL, da Silva DR, Pagliai FA, Pan L, Padgett-Pagliai KA, Blaustein RA, Merli ML, Zhang D, Pereira C, Teplitski M, Chaparro JX, Folimonova SY, Conesa A, Gezan S, Lorca GL, Gonzalez CF. Assessment of unconventional antimicrobial compounds for the control of 'Candidatus Liberibacter asiaticus', the causative agent of citrus greening disease. Sci Rep 2020; 10:5395. [PMID: 32214166 PMCID: PMC7096471 DOI: 10.1038/s41598-020-62246-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Accepted: 03/11/2020] [Indexed: 01/22/2023] Open
Abstract
In this study, newly identified small molecules were examined for efficacy against ‘Candidatus Liberibacter asiaticus’ in commercial groves of sweet orange (Citrus sinensis) and white grapefruit (Citrus paradisi) trees. We used benzbromarone and/or tolfenamic acid delivered by trunk injection. We evaluated safety and efficacy parameters by performing RNAseq of the citrus host responses, 16S rRNA gene sequencing to characterize citrus-associated microbial communities during treatment, and qRT-PCR as an indirect determination of ‘Ca. L. asiaticus’ viability. Analyses of the C. sinensis transcriptome indicated that each treatment consistently induced genes associated with normal metabolism and growth, without compromising tree viability or negatively affecting the indigenous citrus-associated microbiota. It was found that treatment-associated reduction in ‘Ca. L. asiaticus’ was positively correlated with the proliferation of several core taxa related with citrus health. No symptoms of phytotoxicity were observed in any of the treated trees. Trials were also performed in commercial groves to examine the effect of each treatment on fruit productivity, juice quality and efficacy against ‘Ca. L. asiaticus’. Increased fruit production (15%) was observed in C. paradisi following twelve months of treatment with benzbromarone and tolfenamic acid. These results were positively correlated with decreased ‘Ca. L. asiaticus’ transcriptional activity in root samples.
Collapse
Affiliation(s)
- Christopher L Gardner
- Microbiology and Cell Science Department, Genetics Institute, Institute of Food and Agricultural Science, University of Florida, Gainesville, Florida, United States of America
| | - Danilo R da Silva
- Microbiology and Cell Science Department, Genetics Institute, Institute of Food and Agricultural Science, University of Florida, Gainesville, Florida, United States of America
| | - Fernando A Pagliai
- Microbiology and Cell Science Department, Genetics Institute, Institute of Food and Agricultural Science, University of Florida, Gainesville, Florida, United States of America
| | - Lei Pan
- Microbiology and Cell Science Department, Genetics Institute, Institute of Food and Agricultural Science, University of Florida, Gainesville, Florida, United States of America
| | - Kaylie A Padgett-Pagliai
- Microbiology and Cell Science Department, Genetics Institute, Institute of Food and Agricultural Science, University of Florida, Gainesville, Florida, United States of America
| | - Ryan A Blaustein
- Soil and Water Sciences Department, Genetics Institute, Institute of Food and Agricultural Science, University of Florida, Gainesville, Florida, United States of America
| | - Marcelo L Merli
- Microbiology and Cell Science Department, Genetics Institute, Institute of Food and Agricultural Science, University of Florida, Gainesville, Florida, United States of America
| | - Dan Zhang
- Microbiology and Cell Science Department, Genetics Institute, Institute of Food and Agricultural Science, University of Florida, Gainesville, Florida, United States of America
| | - Cécile Pereira
- Microbiology and Cell Science Department, Genetics Institute, Institute of Food and Agricultural Science, University of Florida, Gainesville, Florida, United States of America
| | - Max Teplitski
- Soil and Water Sciences Department, Genetics Institute, Institute of Food and Agricultural Science, University of Florida, Gainesville, Florida, United States of America
| | - Jose X Chaparro
- Fruit Tree Breeding and Genetics, Horticultural Sciences Department, Institute of Food and Agricultural Science, University of Florida, Gainesville, Florida, United States of America
| | - Svetlana Y Folimonova
- Plant Pathology Department, Institute of Food and Agricultural Science, University of Florida, Gainesville, FL, 32611, USA
| | - Ana Conesa
- Microbiology and Cell Science Department, Genetics Institute, Institute of Food and Agricultural Science, University of Florida, Gainesville, Florida, United States of America
| | - Salvador Gezan
- School of Forest Resources and Conservation, Institute of Food and Agricultural Science, University of Florida, Gainesville, Florida, United States of America
| | - Graciela L Lorca
- Microbiology and Cell Science Department, Genetics Institute, Institute of Food and Agricultural Science, University of Florida, Gainesville, Florida, United States of America
| | - Claudio F Gonzalez
- Microbiology and Cell Science Department, Genetics Institute, Institute of Food and Agricultural Science, University of Florida, Gainesville, Florida, United States of America.
| |
Collapse
|
49
|
Li H, Ying X, Shang L, Redfern B, Kypraios N, Xie X, Xu F, Wang S, Zhang J, Jian H, Yu H, Lv D. Heterologous Expression of CLIBASIA_03915/CLIBASIA_04250 by Tobacco Mosaic Virus Resulted in Phloem Necrosis in the Senescent Leaves of Nicotiana benthamiana. Int J Mol Sci 2020; 21:E1414. [PMID: 32093101 PMCID: PMC7073121 DOI: 10.3390/ijms21041414] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Revised: 02/15/2020] [Accepted: 02/17/2020] [Indexed: 12/02/2022] Open
Abstract
Huanglongbing (HLB), also known as citrus greening, is the most notorious citrus disease worldwide. Candidatus Liberibacter asiaticus (CaLas) is a phloem-restricted bacterium associated with HLB. Because there is no mutant library available, the pathogenesis of CaLas is obscure. In this study, we employed tobacco mosaic virus (TMV) to express two mature secretion proteins CLIBASIA_03915 (m03915) and CLIBASIA_04250 (m04250) in Nicotiana benthamiana (N. benthamiana). Phloem necrosis was observed in the senescent leaves of N. benthamiana that expressed the two low molecular weight proteins, while no phloem necrosis was observed in the plants that expressed the control, green fluorescent protein (GFP). Additionally, no phloem necrosis was observed in the senescent leaves of N. benthamiana that expressed the null mutation of m03915 and frameshifting m04250. The subcellular localizations of m03915 and m04250 were determined by fusion with GFP using confocal microscopy. The subcellular localization of m03915 was found to be as free GFP without a nuclear localization sequence (NLS). However, m04250 did have an NLS. Yeast two-hybrid (Y2H) was carried out to probe the citrus proteins interacting with m03915 and m04250. Six citrus proteins were found to interact with m03915. The identified proteins were involved in the metabolism of compounds, transcription, response to abiotic stress, ubiquitin-mediated protein degradation, etc. The prey of m04250 was involved in the processing of specific pre-mRNAs. Identification of new virulence factors of CaLas will give insight into the pathogenesis of CaLas, and therefore, it will eventually help develop the HLB-resistant citrus.
Collapse
Affiliation(s)
- Hui Li
- College of Agronomy and Biotechnology, Southwest University, Chongqing 400715, China; (H.L.); (L.S.); (H.J.)
- State Cultivation Base of Crop Stress Biology for Southern Mountainous Land of Southwest University, Chongqing 400715, China
| | - Xiaobao Ying
- Gulf Coast Research and Education Center, University of Florida, Wimauma, FL 33598, USA; (X.Y.); (B.R.); (N.K.)
| | - Lina Shang
- College of Agronomy and Biotechnology, Southwest University, Chongqing 400715, China; (H.L.); (L.S.); (H.J.)
| | - Bryce Redfern
- Gulf Coast Research and Education Center, University of Florida, Wimauma, FL 33598, USA; (X.Y.); (B.R.); (N.K.)
| | - Nicholas Kypraios
- Gulf Coast Research and Education Center, University of Florida, Wimauma, FL 33598, USA; (X.Y.); (B.R.); (N.K.)
| | - Xuejun Xie
- Changzhou Institute of Technology, Changzhou 213032, China;
| | - FeiFei Xu
- Heilongjiang Academy of Agricultural Sciences, Harbin 10086, China (S.W.); (J.Z.); (H.Y.)
| | - Shaopeng Wang
- Heilongjiang Academy of Agricultural Sciences, Harbin 10086, China (S.W.); (J.Z.); (H.Y.)
| | - Jinghua Zhang
- Heilongjiang Academy of Agricultural Sciences, Harbin 10086, China (S.W.); (J.Z.); (H.Y.)
| | - Hongju Jian
- College of Agronomy and Biotechnology, Southwest University, Chongqing 400715, China; (H.L.); (L.S.); (H.J.)
- State Cultivation Base of Crop Stress Biology for Southern Mountainous Land of Southwest University, Chongqing 400715, China
| | - Hongtao Yu
- Heilongjiang Academy of Agricultural Sciences, Harbin 10086, China (S.W.); (J.Z.); (H.Y.)
| | - Dianqiu Lv
- College of Agronomy and Biotechnology, Southwest University, Chongqing 400715, China; (H.L.); (L.S.); (H.J.)
- State Cultivation Base of Crop Stress Biology for Southern Mountainous Land of Southwest University, Chongqing 400715, China
| |
Collapse
|
50
|
Andrade MO, Pang Z, Achor DS, Wang H, Yao T, Singer BH, Wang N. The flagella of 'Candidatus Liberibacter asiaticus' and its movement in planta. MOLECULAR PLANT PATHOLOGY 2020; 21:109-123. [PMID: 31721403 PMCID: PMC6913195 DOI: 10.1111/mpp.12884] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Citrus huanglongbing (HLB) is the most devastating citrus disease worldwide. 'Candidatus Liberibacter asiaticus' (Las) is the most prevalent HLB causal agent that is yet to be cultured. Here, we analysed the flagellar genes of Las and Rhizobiaceae and observed two characteristics unique to the flagellar proteins of Las: (i) a shorter primary structure of the rod capping protein FlgJ than other Rhizobiaceae bacteria and (ii) Las contains only one flagellin-encoding gene flaA (CLIBASIA_02090), whereas other Rhizobiaceae species carry at least three flagellin-encoding genes. Only flgJAtu but not flgJLas restored the swimming motility of Agrobacterium tumefaciens flgJ mutant. Pull-down assays demonstrated that FlgJLas interacts with FlgB but not with FliE. Ectopic expression of flaALas in A. tumefaciens mutants restored the swimming motility of ∆flaA mutant and ∆flaAD mutant, but not that of the null mutant ∆flaABCD. No flagellum was observed for Las in citrus and dodder. The expression of flagellar genes was higher in psyllids than in planta. In addition, western blotting using flagellin-specific antibody indicates that Las expresses flagellin protein in psyllids, but not in planta. The flagellar features of Las in planta suggest that Las movement in the phloem is not mediated by flagella. We also characterized the movement of Las after psyllid transmission into young flush. Our data support a model that Las remains inside young flush after psyllid transmission and before the flush matures. The delayed movement of Las out of young flush after psyllid transmission provides opportunities for targeted treatment of young flush for HLB control.
Collapse
Affiliation(s)
- Maxuel O. Andrade
- Citrus Research and Education CenterDepartment of Microbiology and Cell ScienceUniversity of Florida/Institute of Food and Agricultural SciencesLake AlfredFLUSA
| | - Zhiqian Pang
- Citrus Research and Education CenterDepartment of Microbiology and Cell ScienceUniversity of Florida/Institute of Food and Agricultural SciencesLake AlfredFLUSA
| | - Diann S. Achor
- Citrus Research and Education CenterDepartment of Microbiology and Cell ScienceUniversity of Florida/Institute of Food and Agricultural SciencesLake AlfredFLUSA
| | - Han Wang
- Citrus Research and Education CenterDepartment of Microbiology and Cell ScienceUniversity of Florida/Institute of Food and Agricultural SciencesLake AlfredFLUSA
| | - Tingshan Yao
- Citrus Research and Education CenterDepartment of Microbiology and Cell ScienceUniversity of Florida/Institute of Food and Agricultural SciencesLake AlfredFLUSA
- National Engineering Research Center for Citrus, Citrus Research Institute, Southwest UniversityChongqing400712People’s Republic of China
| | - Burton H. Singer
- Emerging Pathogens InstituteUniversity of FloridaGainesvilleFLUSA
| | - Nian Wang
- Citrus Research and Education CenterDepartment of Microbiology and Cell ScienceUniversity of Florida/Institute of Food and Agricultural SciencesLake AlfredFLUSA
| |
Collapse
|