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Xia K, Feng Z, Zhang X, Zhou Y, Zhu H, Yao Q. Potential functions of the shared bacterial taxa in the citrus leaf midribs determine the symptoms of Huanglongbing. FRONTIERS IN PLANT SCIENCE 2023; 14:1270929. [PMID: 38034569 PMCID: PMC10682189 DOI: 10.3389/fpls.2023.1270929] [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: 08/01/2023] [Accepted: 10/30/2023] [Indexed: 12/02/2023]
Abstract
Instruction Citrus is a globally important fruit tree whose microbiome plays a vital role in its growth, adaptability, and resistance to stress. Methods With the high throughput sequencing of 16S rRNA genes, this study focused on analyzing the bacterial community, especially in the leaf midribs, of healthy and Huanglongbing (HLB)-infected plants. Results We firstly identified the shared bacterial taxa in the midribs of both healthy and HLB-infected plants, and then analyzed their functions. Results showed that the shared bacterial taxa in midribs belonged to 62 genera, with approximately 1/3 of which modified in the infected samples. Furthermore, 366 metabolic pathways, 5851 proteins, and 1833 enzymes in the shared taxa were predicted. Among these, three metabolic pathways and one protein showed significant importance in HLB infection. With the random forest method, six genera were identified to be significantly important for HLB infection. Notably, four of these genera were also among the significantly different shared taxa. Further functional characterization of these four genera revealed that Pseudomonas and Erwinia likely contributed to plant defense against HLB, while Streptomyces might have implications for plant defense against HLB or the pathogenicity of Candidatus Liberibacter asiaticus (CLas). Disccusion Overall, our study highlights that the functions of the shared taxa in leaf midribs are distinguished between healthy and HLB-infected plants, and these microbiome-based findings can contribute to the management and protection of citrus crops against CLas.
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Affiliation(s)
- Kaili Xia
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (South China), Ministry of Agriculture and Rural Affairs, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, College of Horticulture, South China Agricultural University, Guangzhou, China
- Key Laboratory of Agricultural Microbiomics and Precision Application (MARA), Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Key Laboratory of Agricultural Microbiome (MARA), State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China
| | - Zengwei Feng
- Key Laboratory of Agricultural Microbiomics and Precision Application (MARA), Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Key Laboratory of Agricultural Microbiome (MARA), State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China
| | - Xianjiao Zhang
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (South China), Ministry of Agriculture and Rural Affairs, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, College of Horticulture, South China Agricultural University, Guangzhou, China
- Key Laboratory of Agricultural Microbiomics and Precision Application (MARA), Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Key Laboratory of Agricultural Microbiome (MARA), State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China
| | - Yang Zhou
- Key Laboratory of Agricultural Microbiomics and Precision Application (MARA), Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Key Laboratory of Agricultural Microbiome (MARA), State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China
| | - Honghui Zhu
- Key Laboratory of Agricultural Microbiomics and Precision Application (MARA), Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Key Laboratory of Agricultural Microbiome (MARA), State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China
| | - Qing Yao
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (South China), Ministry of Agriculture and Rural Affairs, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, College of Horticulture, South China Agricultural University, Guangzhou, China
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Nehela Y, Killiny N. Gamma-Aminobutyric Acid Accumulation Contributes to Citrus sinensis Response against ' Candidatus Liberibacter Asiaticus' via Modulation of Multiple Metabolic Pathways and Redox Status. PLANTS (BASEL, SWITZERLAND) 2023; 12:3753. [PMID: 37960112 PMCID: PMC10650511 DOI: 10.3390/plants12213753] [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: 10/30/2023] [Accepted: 10/31/2023] [Indexed: 11/15/2023]
Abstract
Huanglongbing (HLB; also known as citrus greening) is the most destructive bacterial disease of citrus worldwide with no known sustainable cure yet. Herein, we used non-targeted metabolomics and transcriptomics to prove that γ-aminobutyric acid (GABA) accumulation might influence the homeostasis of several metabolic pathways, as well as antioxidant defense machinery, and their metabolism-related genes. Overall, 41 metabolites were detected in 'Valencia' sweet orange (Citrus sinensis) leaf extract including 19 proteinogenic amino acids (PAA), 10 organic acids, 5 fatty acids, and 9 other amines (four phenolic amines and three non-PAA). Exogenous GABA application increased most PAA in healthy (except L-threonine, L-glutamine, L-glutamic acid, and L-methionine) and 'Candidatus L. asiaticus'-infected citrus plants (with no exception). Moreover, GABA accumulation significantly induced L-tryptophan, L-phenylalanine, and α-linolenic acid, the main precursors of auxins, salicylic acid (SA), and jasmonic acid (JA), respectively. Furthermore, GABA supplementation upregulated most, if not all, of amino acids, phenolic amines, phytohormone metabolism-related, and GABA shunt-associated genes in both healthy and 'Ca. L. asiaticus'-infected leaves. Moreover, although 'Ca. L. asiaticus' induced the accumulation of H2O2 and O2•- and generated strong oxidative stress in infected leaves, GABA possibly stimulates the activation of a multilayered antioxidative system to neutralize the deleterious effect of reactive oxygen species (ROS) and maintain redox status within infected leaves. This complex system comprises two major components: (i) the enzymatic antioxidant defense machinery (six POXs, four SODs, and CAT) that serves as the front line in antioxidant defenses, and (ii) the non-enzymatic antioxidant defense machinery (phenolic acids and phenolic amines) that works as a second defense line against 'Ca. L. asiaticus'-induced ROS in citrus infected leaves. Collectively, our findings suggest that GABA might be a promising alternative eco-friendly strategy that helps citrus trees battle HLB particularly, and other diseases in general.
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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;
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Sinha S, Thakuria D, Chaliha C, Uzir P, Hazarika S, Dutta P, Singh AK, Laloo B. Plant growth-promoting traits of culturable seed microbiome of citrus species from Purvanchal Himalaya. FRONTIERS IN PLANT SCIENCE 2023; 14:1104927. [PMID: 37492766 PMCID: PMC10365123 DOI: 10.3389/fpls.2023.1104927] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Accepted: 05/30/2023] [Indexed: 07/27/2023]
Abstract
Despite Northeastern India being "Treasure House of Citrus Genetic Wealth," genetic erosion of citrus diversity poses severe concern with a corresponding loss in seed microbial diversity. The seed microbiome of citrus species unique to the Purvanchal Himalaya is seldom explored for their use in sustainable orchard management. Isolation and characterization of culturable seed microbiomes of eight citrus species, namely, Citrus reticulata Blanco, C. grandis (L.) Osbeck, C. latipes Tanaka, C. megaloxycarpa Lushaigton, C. jambhiri Lush, C. sinensis (L.) Osbeck, C. macroptera Montr, and C. indica Tanaka collected from NE India were carried out. The isolates were then screened for an array of plant growth-promoting (PGP) traits [indole acetic acid (IAA) production, N2 fixation, phosphate and zinc complex dissolution, siderophores, and Hydrogen Cyanide (HCN) production]. The pure culture isolates of seed microbiomes were capable of dissolving insoluble Ca3(PO4)2 (1.31-4.84 µg Pi ml-1 h-1), Zn3(PO4)2 (2.44-3.16 µg Pi ml-1 h-1), AlPO4 (1.74-3.61 µg Pi ml-1 h-1), and FePO4 (1.54-4.61µg Pi ml-1 h-1), mineralized phytate (12.17-18.00 µg Pi ml-1 h-1) and produced IAA-like substances (4.8-187.29 µg ml-1 h-1). A few isolates of the seed microbiome were also able to fix nitrogen, secrete siderophore-like compounds and HCN, and dissolve ZnSO4 and ZnO. The 16S ribosomal Ribonucleic Acid (rRNA)-based taxonomic findings revealed that Bacillus was the most dominant genus among the isolates across citrus species. Isolates CG2-1, CME6-1, CME6-4, CME6-5, CME6-9, CJ7-1, CMA10-1, CI11-3, and CI11-4 were identified as promising bioinoculants for development of microbial consortium having multifaceted PGP traits for nutritional benefits of nitrogen, phosphorus and zinc, and IAA hormonal benefits to citrus crops for better fitness in acid soils.
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Affiliation(s)
- Sakshi Sinha
- School of Natural Resource Management, College of Post Graduate Studies in Agricultural Sciences, Central Agricultural University (Imphal), Umiam, Meghalaya, India
| | - Dwipendra Thakuria
- School of Natural Resource Management, College of Post Graduate Studies in Agricultural Sciences, Central Agricultural University (Imphal), Umiam, Meghalaya, India
| | - Chayanika Chaliha
- School of Natural Resource Management, College of Post Graduate Studies in Agricultural Sciences, Central Agricultural University (Imphal), Umiam, Meghalaya, India
| | - Panchali Uzir
- School of Natural Resource Management, College of Post Graduate Studies in Agricultural Sciences, Central Agricultural University (Imphal), Umiam, Meghalaya, India
| | - Samarendra Hazarika
- Division of System Research and Engineering, Indian Council of Agricultural Research (ICAR) Research Complex for North Eastern Hill Region, Umiam, Meghalaya, India
| | - Pranab Dutta
- School of Crop Protection, College of Post Graduate Studies in Agricultural Sciences, Central Agricultural University (Imphal), Umiam, Meghalaya, India
| | - A. K. Singh
- School of Natural Resource Management, College of Post Graduate Studies in Agricultural Sciences, Central Agricultural University (Imphal), Umiam, Meghalaya, India
| | - Bingiala Laloo
- School of Crop Improvement, College of Post Graduate Studies in Agricultural Sciences, Central Agricultural University (Imphal), Umiam, Meghalaya, India
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Weber KC, Mahmoud LM, Stanton D, Welker S, Qiu W, Grosser JW, Levy A, Dutt M. Insights into the mechanism of Huanglongbing tolerance in the Australian finger lime ( Citrus australasica). FRONTIERS IN PLANT SCIENCE 2022; 13:1019295. [PMID: 36340410 PMCID: PMC9634478 DOI: 10.3389/fpls.2022.1019295] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Accepted: 09/22/2022] [Indexed: 05/13/2023]
Abstract
The Australian finger lime (Citrus australasica) is tolerant to Huanglongbing (HLB; Citrus greening). This species can be utilized to develop HLB tolerant citrus cultivars through conventional breeding and biotechnological approaches. In this report, we conducted a comprehensive analysis of transcriptomic data following a non-choice infection assay to understand the CaLas tolerance mechanisms in the finger lime. After filtering 3,768 differentially expressed genes (DEGs), 2,396 were downregulated and 1,372 were upregulated in CaLas-infected finger lime compared to CaLas-infected HLB-susceptible 'Valencia' sweet orange. Comparative analyses revealed several DEGs belonging to cell wall, β-glucanase, proteolysis, R genes, signaling, redox state, peroxidases, glutathione-S-transferase, secondary metabolites, and pathogenesis-related (PR) proteins categories. Our results indicate that the finger lime has evolved specific redox control systems to mitigate the reactive oxygen species and modulate the plant defense response. We also identified candidate genes responsible for the production of Cys-rich secretory proteins and Pathogenesis-related 1 (PR1-like) proteins that are highly upregulated in infected finger lime relative to noninfected and infected 'Valencia' sweet orange. Additionally, the anatomical analysis of phloem and stem tissues in finger lime and 'Valencia' suggested better regeneration of phloem tissues in finger lime in response to HLB infection. Analysis of callose formation following infection revealed a significant difference in the production of callose plugs between the stem phloem of CaLas+ 'Valencia' sweet orange and finger lime. Understanding the mechanism of resistance will help the scientific community design strategies to protect trees from CaLas infection and assist citrus breeders in developing durable HLB tolerant citrus varieties.
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Affiliation(s)
- Kyle C. Weber
- Citrus Research and Education Center, University of Florida, Lake Alfred, FL, United States
| | - Lamiaa M. Mahmoud
- Citrus Research and Education Center, University of Florida, Lake Alfred, FL, United States
- Pomology Department, Faculty of Agriculture, Mansoura University, Mansoura, Egypt
| | - Daniel Stanton
- Citrus Research and Education Center, University of Florida, Lake Alfred, FL, United States
| | - Stacy Welker
- Citrus Research and Education Center, University of Florida, Lake Alfred, FL, United States
| | - Wenming Qiu
- Institute of Fruit and Tea, Hubei Academy of Agricultural Sciences, Wuhan, China
| | - Jude W. Grosser
- Citrus Research and Education Center, University of Florida, Lake Alfred, FL, United States
| | - Amit Levy
- Citrus Research and Education Center, University of Florida, Lake Alfred, FL, United States
| | - Manjul Dutt
- Citrus Research and Education Center, University of Florida, Lake Alfred, FL, United States
- *Correspondence: Manjul Dutt,
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