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Wang J, Liao Z, Jin X, Liao L, Zhang Y, Zhang R, Zhao X, Qin H, Chen J, He Y, Zhuang C, Tang J, Huang S. Xanthomonas oryzae pv. oryzicola effector Tal10a directly activates rice OsHXK5 expression to facilitate pathogenesis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2024; 119:2423-2436. [PMID: 38995679 DOI: 10.1111/tpj.16929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 04/17/2024] [Accepted: 07/01/2024] [Indexed: 07/13/2024]
Abstract
Bacterial leaf streak (BLS), caused by Xanthomonas oryzae pv. oryzicola (Xoc), is a major bacterial disease in rice. Transcription activator-like effectors (TALEs) from Xanthomonas can induce host susceptibility (S) genes and facilitate infection. However, knowledge of the function of Xoc TALEs in promoting bacterial virulence is limited. In this study, we demonstrated the importance of Tal10a for the full virulence of Xoc. Through computational prediction and gene expression analysis, we identified the hexokinase gene OsHXK5 as a host target of Tal10a. Tal10a directly binds to the gene promoter region and activates the expression of OsHXK5. CRISPR/Cas9-mediated gene editing in the effector binding element (EBE) of OsHXK5 significantly increases rice resistance to Xoc, while OsHXK5 overexpression enhances the susceptibility of rice plants and impairs rice defense responses. Moreover, simultaneous editing of the promoters of OsSULTR3;6 and OsHXK5 confers robust resistance to Xoc in rice. Taken together, our findings highlight the role of Tal10a in targeting OsHXK5 to promote infection and suggest that OsHXK5 represents a potential target for engineering rice resistance to Xoc.
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Affiliation(s)
- Jiuxiang Wang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning, 530004, Guangxi, China
| | - Zhouxiang Liao
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning, 530004, Guangxi, China
- School of Public Health, Guangxi Medical University, Nanning, 530021, China
| | - Xia Jin
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning, 530004, Guangxi, China
| | - Lindong Liao
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning, 530004, Guangxi, China
| | - Yaqi Zhang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning, 530004, Guangxi, China
| | - Rongbo Zhang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning, 530004, Guangxi, China
| | - Xiyao Zhao
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning, 530004, Guangxi, China
| | - Huajun Qin
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning, 530004, Guangxi, China
| | - Jianghong Chen
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning, 530004, Guangxi, China
| | - Yongqiang He
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning, 530004, Guangxi, China
- National Demonstration Center for Experimental Plant Science Education, College of Agriculture, Guangxi University, Nanning, 530004, Guangxi, China
| | - Chuxiong Zhuang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Sciences, South China Agricultural University, Guangzhou, 510642, China
| | - Jiliang Tang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning, 530004, Guangxi, China
| | - Sheng Huang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning, 530004, Guangxi, China
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Roussin-Léveillée C, Rossi CAM, Castroverde CDM, Moffett P. The plant disease triangle facing climate change: a molecular perspective. TRENDS IN PLANT SCIENCE 2024; 29:895-914. [PMID: 38580544 DOI: 10.1016/j.tplants.2024.03.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2023] [Revised: 02/27/2024] [Accepted: 03/06/2024] [Indexed: 04/07/2024]
Abstract
Variations in climate conditions can dramatically affect plant health and the generation of climate-resilient crops is imperative to food security. In addition to directly affecting plants, it is predicted that more severe climate conditions will also result in greater biotic stresses. Recent studies have identified climate-sensitive molecular pathways that can result in plants being more susceptible to infection under unfavorable conditions. Here, we review how expected changes in climate will impact plant-pathogen interactions, with a focus on mechanisms regulating plant immunity and microbial virulence strategies. We highlight the complex interactions between abiotic and biotic stresses with the goal of identifying components and/or pathways that are promising targets for genetic engineering to enhance adaptation and strengthen resilience in dynamically changing environments.
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Affiliation(s)
| | - Christina A M Rossi
- Department of Biology, Wilfrid Laurier University, Waterloo, Ontario, N2L 3C5, Canada
| | | | - Peter Moffett
- Centre SÈVE, Département de Biologie, Université de Sherbrooke, Sherbrooke, Québec, Canada.
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Roussin-Léveillée C, Mackey D, Ekanayake G, Gohmann R, Moffett P. Extracellular niche establishment by plant pathogens. Nat Rev Microbiol 2024; 22:360-372. [PMID: 38191847 DOI: 10.1038/s41579-023-00999-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/21/2023] [Indexed: 01/10/2024]
Abstract
The plant extracellular space, referred to as the apoplast, is inhabited by a variety of microorganisms. Reflecting the crucial nature of this compartment, both plants and microorganisms seek to control, exploit and respond to its composition. Upon sensing the apoplastic environment, pathogens activate virulence programmes, including the delivery of effectors with well-established roles in suppressing plant immunity. We posit that another key and foundational role of effectors is niche establishment - specifically, the manipulation of plant physiological processes to enrich the apoplast in water and nutritive metabolites. Facets of plant immunity counteract niche establishment by restricting water, nutrients and signals for virulence activation. The complex competition to control and, in the case of pathogens, exploit the apoplast provides remarkable insights into the nature of virulence, host susceptibility, host defence and, ultimately, the origin of phytopathogenesis. This novel framework focuses on the ecology of a microbial niche and highlights areas of future research on plant-microorganism interactions.
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Affiliation(s)
| | - David Mackey
- Department of Horticulture and Crop Science, The Ohio State University, Columbus, OH, USA.
- Department of Molecular Genetics, The Ohio State University, Columbus, OH, USA.
- Center for Applied Plant Sciences, The Ohio State University, Columbus, OH, USA.
| | - Gayani Ekanayake
- Department of Horticulture and Crop Science, The Ohio State University, Columbus, OH, USA
| | - Reid Gohmann
- Department of Horticulture and Crop Science, The Ohio State University, Columbus, OH, USA
| | - Peter Moffett
- Centre SÈVE, Département de Biologie, Université de Sherbrooke, Sherbrooke, Québec, Canada.
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Roman-Reyna V, Heiden N, Butchacas J, Toth H, Cooperstone JL, Jacobs JM. The timing of bacterial mesophyll infection shapes the leaf chemical landscape. Microbiol Spectr 2024; 12:e0413823. [PMID: 38426767 PMCID: PMC10986523 DOI: 10.1128/spectrum.04138-23] [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: 12/08/2023] [Accepted: 02/14/2024] [Indexed: 03/02/2024] Open
Abstract
Chemistry in eukaryotic intercellular spaces is shaped by both hosts and symbiotic microorganisms such as bacteria. Pathogenic microorganisms like barley-associated Xanthomonas translucens (Xt) swiftly overtake the inner leaf tissue becoming the dominant microbial community member during disease development. The dynamic metabolic changes due to Xt pathogenesis in the mesophyll spaces remain unknown. Genomic group I of Xt consists of two barley-infecting lineages: pathovar translucens (Xtt) and pathovar undulosa (Xtu). Xtu and Xtt, although genomically distinct, cause similar water-soaked lesions. To define the metabolic signals associated with inner leaf colonization, we used untargeted metabolomics to characterize Xtu and Xtt metabolism signatures associated with mesophyll growth. We found that mesophyll apoplast fluid from infected tissue yielded a distinct metabolic profile and shift from catabolic to anabolic processes over time compared to water-infiltrated control. The pathways with the most differentially expressed metabolites by time were glycolysis, tricarboxylic acid cycle, sucrose metabolism, pentose interconversion, amino acids, galactose, and purine metabolism. Hierarchical clustering and principal component analysis showed that metabolic changes were more affected by the time point rather than the individual colonization of the inner leaves by Xtt compared to Xtu. Overall, in this study, we identified metabolic pathways that explain carbon and nitrogen usage during host-bacterial interactions over time for mesophyll tissue colonization. This foundational research provides initial insights into shared metabolic strategies of inner leaf colonization niche occupation by related but phylogenetically distinct phyllosphere bacteria. IMPORTANCE The phyllosphere is a habitat for microorganisms including pathogenic bacteria. Metabolic shifts in the inner leaf spaces for most plant-microbe interactions are unknown, especially for Xanthomonas species in understudied plants like barley (Hordeum vulgare). Xanthomonas translucens pv. translucens (Xtt) and Xanthomonas translucens pv. undulosa (Xtu) are phylogenomically distinct, but both colonize barley leaves for pathogenesis. In this study, we used untargeted metabolomics to shed light on Xtu and Xtt metabolic signatures. Our findings revealed a dynamic metabolic landscape that changes over time, rather than exhibiting a pattern associated with individual pathovars. These results provide initial insights into the metabolic mechanisms of X. translucens inner leaf pathogenesis.
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Affiliation(s)
- Veronica Roman-Reyna
- Department of Plant Pathology, The Ohio State University, Columbus, Ohio, USA
- Infectious Diseases Institute, The Ohio State University, Columbus, Ohio, USA
| | - Nathaniel Heiden
- Department of Plant Pathology, The Ohio State University, Columbus, Ohio, USA
- Infectious Diseases Institute, The Ohio State University, Columbus, Ohio, USA
| | - Jules Butchacas
- Department of Plant Pathology, The Ohio State University, Columbus, Ohio, USA
- Infectious Diseases Institute, The Ohio State University, Columbus, Ohio, USA
| | - Hannah Toth
- Department of Plant Pathology, The Ohio State University, Columbus, Ohio, USA
- Infectious Diseases Institute, The Ohio State University, Columbus, Ohio, USA
| | - Jessica L. Cooperstone
- Department of Horticulture and Crop Science, The Ohio State University, Columbus, Ohio, USA
- Department of Food Science and Technology, The Ohio State University, Columbus, Ohio, USA
| | - Jonathan M. Jacobs
- Department of Plant Pathology, The Ohio State University, Columbus, Ohio, USA
- Infectious Diseases Institute, The Ohio State University, Columbus, Ohio, USA
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Chicowski AS, Bredow M, Utiyama AS, Marcelino‐Guimarães FC, Whitham SA. Soybean-Phakopsora pachyrhizi interactions: towards the development of next-generation disease-resistant plants. PLANT BIOTECHNOLOGY JOURNAL 2024; 22:296-315. [PMID: 37883664 PMCID: PMC10826999 DOI: 10.1111/pbi.14206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 09/19/2023] [Accepted: 10/08/2023] [Indexed: 10/28/2023]
Abstract
Soybean rust (SBR), caused by the obligate biotrophic fungus Phakopsora pachyrhizi, is a devastating foliar disease threatening soybean production. To date, no commercial cultivars conferring durable resistance to SBR are available. The development of long-lasting SBR resistance has been hindered by the lack of understanding of this complex pathosystem, encompassing challenges posed by intricate genetic structures in both the host and pathogen, leading to a gap in the knowledge of gene-for-gene interactions between soybean and P. pachyrhizi. In this review, we focus on recent advancements and emerging technologies that can be used to improve our understanding of the P. pachyrhizi-soybean molecular interactions. We further explore approaches used to combat SBR, including conventional breeding, transgenic approaches and RNA interference, and how advances in our understanding of plant immune networks, the availability of new molecular tools, and the recent sequencing of the P. pachyrhizi genome could be used to aid in the development of better genetic resistance against SBR. Lastly, we discuss the research gaps of this pathosystem and how new technologies can be used to shed light on these questions and to develop durable next-generation SBR-resistant soybean plants.
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Affiliation(s)
- Aline Sartor Chicowski
- Department of Plant Pathology, Entomology and MicrobiologyIowa State UniversityAmesIowaUSA
| | - Melissa Bredow
- Department of Plant Pathology, Entomology and MicrobiologyIowa State UniversityAmesIowaUSA
| | - Alice Satiko Utiyama
- Brazilian Agricultural Research Corporation – National Soybean Research Center (Embrapa Soja)LondrinaParanáBrazil
- Department of AgronomyFederal University of ViçosaViçosaMinas GeraisBrazil
| | | | - Steven A. Whitham
- Department of Plant Pathology, Entomology and MicrobiologyIowa State UniversityAmesIowaUSA
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Gutierrez-Castillo DE, Barrett E, Roberts R. A recently collected Xanthomonas translucens isolate encodes TAL effectors distinct from older, less virulent isolates. Microb Genom 2024; 10:001177. [PMID: 38189214 PMCID: PMC10868612 DOI: 10.1099/mgen.0.001177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Accepted: 12/19/2023] [Indexed: 01/09/2024] Open
Abstract
Xanthomonas translucens, the causal agent of bacterial leaf streak disease (BLS) in cereals, is a re-emerging pathogen that is becoming increasingly destructive across the world. While BLS has caused yield losses in the past, there is anecdotal evidence that newer isolates may be more virulent. We observed that two X. translucens isolates collected from two sites in Colorado, USA, are more aggressive on current wheat and barley varieties compared to older isolates, and we hypothesize that genetic changes between recent and older isolates contribute to the differences in isolate aggressiveness. To test this, we phenotyped and genetically characterized two X. translucens isolates collected from Colorado in 2018, which we designated CO236 (from barley) and CO237 (from wheat). Using pathovar-specific phenotyping and PCR primers, we determined that CO236 belongs to pathovar translucens (Xtt) and CO237 belongs to pathovar undulosa (Xtu). We sequenced the full genomes of the isolates using Oxford Nanopore long-read sequencing, and compared their whole genomes against published X. translucens genomes. This analysis confirmed our pathovar designations for Xtt CO236 and Xtu CO237, and showed that, at the whole-genome level, there were no obvious genomic structural changes between Xtt CO236 and Xtu CO237 and other respective published pathovar genomes. Focusing on pathovar undulosa (Xtu CO237), we then compared putative type III effectors among all available Xtu isolate genomes and found that they were highly conserved. However, there were striking differences in the presence and sequence of various transcription activator-like effectors between Xtu CO237 and published undulosa genomes, which correlate with isolate virulence. Here, we explore the potential implications of the differences in these virulence factors, and provide possible explanations for the increased virulence of recently emerged isolates.
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Affiliation(s)
| | - Emma Barrett
- Department of Agricultural Biology, Colorado State University, Fort Collins, CO, USA
| | - Robyn Roberts
- Department of Agricultural Biology, Colorado State University, Fort Collins, CO, USA
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Ando S, Otawara S, Tabei Y, Tsushima S. Plasmodiophora brassicae affects host gene expression by secreting the transcription factor-type effector PbZFE1. JOURNAL OF EXPERIMENTAL BOTANY 2024; 75:454-467. [PMID: 37738570 DOI: 10.1093/jxb/erad377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2023] [Accepted: 09/20/2023] [Indexed: 09/24/2023]
Abstract
The protist pathogen Plasmodiophora brassicae hijacks the metabolism and development of host cruciferous plants and induces clubroot formation, but little is known about its regulatory mechanisms. Previously, the Pnit2int2 sequence, a sequence around the second intron of the nitrilase gene (BrNIT2) involved in auxin biosynthesis in Brassica rapa ssp. pekinensis, was identified as a specific promoter activated during clubroot formation. In this study, we hypothesized that analysis of the transcriptional regulation of Pnit2int2 could reveal how P. brassicae affects the host gene regulatory system during clubroot development. By yeast one-hybrid screening, the pathogen zinc finger protein PbZFE1 was identified to specifically bind to Pnit2int2. Specific binding of PbZFE1 to Pnit2int2 was also confirmed by electrophoretic mobility shift assay. The binding site of PbZFE1 is essential for promoter activity of Pnit2int2 in clubbed roots of transgenic Arabidopsis thaliana (Pnit2int2-2::GUS), indicating that PbZFE1 is secreted from P. brassicae and functions within plant cells. Ectopic expression of PbZEF1 in A. thaliana delayed growth and flowering time, suggesting that PbZFE1 has significant impacts on host development and metabolic systems. Thus, P. brassicae appears to secrete PbZFE1 into host cells as a transcription factor-type effector during pathogenesis.
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Affiliation(s)
- Sugihiro Ando
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aramakiaza-Aoba, Aoba-ku, Sendai, Miyagi 980-8572, Japan
| | - Shinsuke Otawara
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aramakiaza-Aoba, Aoba-ku, Sendai, Miyagi 980-8572, Japan
| | - Yutaka Tabei
- Division of Plant Sciences, The Institute of Agrobiological Sciences, NARO (NIAS), 2-1-2 Kan-nondai, Tsukuba, Ibaraki 305-8602, Japan
- Department of Food and Life Sciences, Toyo University, 1-1-1 Izumino, Itakura-machi, Ora-gun, Gunma 374-0193, Japan
| | - Seiya Tsushima
- Strategic Planning Headquarters, National Agriculture and Food Research Organization (NARO), 3-1-1 Kan-nondai, Tsukuba, Ibaraki 305-8517, Japan
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Singh N, Ravi B, Saini LK, Pandey GK. Voltage-dependent anion channel 3 (VDAC3) mediates P. syringae induced ABA-SA signaling crosstalk in Arabidopsis thaliana. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2024; 206:108237. [PMID: 38109831 DOI: 10.1016/j.plaphy.2023.108237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 11/04/2023] [Accepted: 11/23/2023] [Indexed: 12/20/2023]
Abstract
Pathogen severely affects plant mitochondrial processes including respiration, however, the roles and mechanism of mitochondrial protein during the immune response remain largely unexplored. The interplay of plant hormone signaling during defense is an outcome of plant pathogen interaction. We recently discovered that the Arabidopsis calcineurin B-like interacting protein kinase 9 (AtCIPK9) interacts with the voltage-dependent anion channel 3 (AtVDAC3) and inhibits MV-induced oxidative damage. Here we report the characterization of AtVDAC3 in an antagonistic interaction pathway between abscisic acid (ABA) and salicylic acid (SA) signaling in Pseudomonas syringae -Arabidopsis interaction. In this study, we observed that mutants of AtVDAC3 were highly susceptible to Pseudomonas syringae infection as compared to the wild type (WT) Arabidopsis plants. Transcripts of VDAC3 and CIPK9 were inducible upon ABA application. Following pathogen exposure, expression analyses of ABA and SA biosynthesis genes indicated that the function of VDAC3 is required for isochorisimate synthase 1 (ICS1) expression but not for Nine-cis-epoxycaotenoid dioxygenase 3 (NCED3) expression. Despite the fact that vdac3 mutants had increased NCED3 expression in response to pathogen challenge, transcripts of ABA sensitive genes such as AtRD22 and AtRAB18 were downregulated even after exogenous ABA application. VDAC3 is required for ABA responsive genes expression upon exogenous ABA application. We also found that Pseudomonas syringae-induced SA signaling is downregulated in vdac3 mutants since overexpression of VDAC3 resulted in hyperaccumulation of Pathogenesis related gene1 (PR1) transcript. Interestingly, ABA application prior to P. syringae inoculation resulted in the upregulation of ABA responsive genes like Responsive to ABA18 (RAB18) and Responsive to dehydration 22 (RD22). Intriguingly, in the absence of AtVDAC3, Pst challenge can dramatically increase ABA-induced RD22 and RAB18 expression. Altogether our results reveal a novel Pathogen-SA-ABA interaction pathway in plants. Our findings show that ABA plays a significant role in modifying plant-pathogen interactions, owing to cross-talk with the biotic stress signaling pathways of ABA and SA.
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Affiliation(s)
- Nidhi Singh
- Department of Plant Molecular Biology, University of Delhi South Campus, Benito Juarez Road, Dhaula Kuan, New Delhi, 110021, India
| | - Barkha Ravi
- Department of Plant Molecular Biology, University of Delhi South Campus, Benito Juarez Road, Dhaula Kuan, New Delhi, 110021, India
| | - Lokesh K Saini
- Department of Plant Molecular Biology, University of Delhi South Campus, Benito Juarez Road, Dhaula Kuan, New Delhi, 110021, India
| | - Girdhar K Pandey
- Department of Plant Molecular Biology, University of Delhi South Campus, Benito Juarez Road, Dhaula Kuan, New Delhi, 110021, India.
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Ledman KE, Roman-Reyna V, Curland RD, Heiden N, Jacobs JM, Dill-Macky R. Comparative Genomics of Xanthomonas translucens pv. undulosa Strains Isolated from Weedy Grasses and Cultivated Wild Rice. PHYTOPATHOLOGY 2023; 113:2083-2090. [PMID: 37260072 DOI: 10.1094/phyto-09-22-0352-sa] [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: 06/02/2023]
Abstract
Bacterial leaf streak (BLS) of wheat (Triticum aestivum), caused by Xanthomonas translucens pv. undulosa, is a disease of major concern in the Northern Great Plains. The host range for X. translucens pv. undulosa is relatively broad, including several small grains and perennial grasses. In Minnesota, X. translucens pv. undulosa was isolated from weedy grasses in and around wheat fields that exhibited BLS symptoms and from cultivated wild rice (Zizania palustris) with symptomatic leaf tissue. Currently, no genomic resources are available for X. translucens pv. undulosa strains isolated from non-wheat hosts. In this study, we sequenced and assembled the complete genomes of five strains isolated from weedy grass hosts, foxtail barley (Hordeum jubatum), green foxtail (Setaria viridis), and wild oat (Avena fatua), and from cultivated wild rice and wheat. These five genomes were compared with the publicly available genomes of seven X. translucens pv. undulosa strains originating from wheat and one genome of an X. translucens pv. secalis strain originating from rye (Secale cereale). Global alignments of the genomes revealed little variation in genomic structures. Average nucleotide identity-based phylogeny and life identification numbers revealed that the strains share ≥99.25% identity. We noted differences in the presence of Type III secreted effectors, including transcription activator-like effectors. Despite differences between strains, we did not identify unique features distinguishing strains isolated from wheat and non-wheat hosts. This study contributes to the availability of genomic data for X. translucens pv. undulosa from non-wheat hosts, thus increasing our understanding of the diversity within the pathogen population.
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Affiliation(s)
- Kristi E Ledman
- Department of Plant Pathology, University of Minnesota, St. Paul, MN
| | - Veronica Roman-Reyna
- Plant Pathology Department, The Ohio State University, Columbus, OH
- Infectious Diseases Institute, The Ohio State University, Columbus, OH
| | - Rebecca D Curland
- Department of Plant Pathology, University of Minnesota, St. Paul, MN
| | - Nathaniel Heiden
- Plant Pathology Department, The Ohio State University, Columbus, OH
- Infectious Diseases Institute, The Ohio State University, Columbus, OH
| | - Jonathan M Jacobs
- Plant Pathology Department, The Ohio State University, Columbus, OH
- Infectious Diseases Institute, The Ohio State University, Columbus, OH
| | - Ruth Dill-Macky
- Department of Plant Pathology, University of Minnesota, St. Paul, MN
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10
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Ledman KE, Osdaghi E, Curland RD, Liu Z, Dill-Macky R. Epidemiology, Host Resistance, and Genomics of the Small Grain Cereals Pathogen Xanthomonas translucens: New Advances and Future Prospects. PHYTOPATHOLOGY 2023; 113:2037-2047. [PMID: 36996338 DOI: 10.1094/phyto-11-22-0403-sa] [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: 06/19/2023]
Abstract
Bacterial leaf streak (BLS) primarily affects barley and wheat and is mainly caused by the pathogens Xanthomonas translucens pv. translucens and X. translucens pv. undulosa, respectively. BLS is distributed globally and poses a risk to food security and the supply of malting barley. X. translucens pv. cerealis can infect both wheat and barley but is rarely isolated from these hosts in natural infections. These pathogens have undergone a confusing taxonomic history, and the biology has been poorly understood, making it difficult to develop effective control measures. Recent advancements in the ability and accessibility to sequence bacterial genomes have shed light on phylogenetic relationships between strains and identified genes that may play a role in virulence, such as those that encode Type III effectors. In addition, sources of resistance to BLS have been identified in barley and wheat lines, and ongoing efforts are being made to map these genes and evaluate germplasm. Although there are still gaps in BLS research, progress has been made in recent years to further understand epidemiology, diagnostics, pathogen virulence, and host resistance.
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Affiliation(s)
- Kristi E Ledman
- Department of Plant Pathology, University of Minnesota, St. Paul, MN, U.S.A
| | - Ebrahim Osdaghi
- Department of Plant Protection, University of Tehran, Karaj, Iran
| | - Rebecca D Curland
- Department of Plant Pathology, University of Minnesota, St. Paul, MN, U.S.A
| | - Zhaohui Liu
- Department of Plant Pathology, North Dakota State University, Fargo, ND, U.S.A
| | - Ruth Dill-Macky
- Department of Plant Pathology, University of Minnesota, St. Paul, MN, U.S.A
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11
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Heiden N, Broders KA, Hutin M, Castro MO, Roman-Reyna V, Toth H, Jacobs JM. Bacterial Leaf Streak Diseases of Plants: Symptom Convergence in Monocot Plants by Distant Pathogenic Xanthomonas Species. PHYTOPATHOLOGY 2023; 113:2048-2055. [PMID: 37996392 DOI: 10.1094/phyto-05-23-0155-ia] [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: 11/25/2023]
Abstract
Bacterial leaf streak (BLS) is a disease of monocot plants caused by Xanthomonas translucens on small grains, X. vasicola on maize and sorghum, and X. oryzae on rice. These three pathogens cause remarkably similar symptomology in their host plants. Despite causing similar symptoms, BLS pathogens are dispersed throughout the larger Xanthomonas phylogeny. Each aforementioned species includes strain groups that do not cause BLS and instead cause vascular disease. In this commentary, we hypothesize that strains of X. translucens, X. vasicola, and X. oryzae convergently evolved to cause BLS due to shared evolutionary pressures. We examined the diversity of secreted effectors, which may be important virulence factors for BLS pathogens and their evolution. We discuss evidence that differences in gene regulation and abilities to manipulate plant hormones may also separate BLS pathogens from other Xanthomonas species or pathovars. BLS is becoming an increasing issue across the three pathosystems. Overall, we hope that a better understanding of conserved mechanisms used by BLS pathogens will enable researchers to translate findings across production systems and guide approaches to control this (re)emerging threat.
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Affiliation(s)
- Nathaniel Heiden
- Department of Plant Pathology, The Ohio State University, Columbus, OH 43210, U.S.A
- Infectious Diseases Institute, The Ohio State University, Columbus, OH 43210, U.S.A
| | - Kirk A Broders
- U.S. Department of Agriculture-Agricultural Research Service, National Center for Agricultural Utilization Research, Mycotoxin Prevention and Applied Microbiology Research Unit, Peoria, IL 61604, U.S.A
| | - Mathilde Hutin
- Plant Health Institute of Montpellier, University of Montpellier, IRD, CIRAD, INRAE, Institut Agro, Montpellier, France
| | - Mary Ortiz Castro
- Horticulture and Extension Programs, Colorado State University, Castle Rock, CO 80106, U.S.A
| | - Verónica Roman-Reyna
- Department of Plant Pathology, The Ohio State University, Columbus, OH 43210, U.S.A
- Infectious Diseases Institute, The Ohio State University, Columbus, OH 43210, U.S.A
- Department of Plant Pathology and Environmental Microbiology, Pennsylvania State University, University Park, PA 16802, U.S.A
| | - Hannah Toth
- Department of Plant Pathology, The Ohio State University, Columbus, OH 43210, U.S.A
- Infectious Diseases Institute, The Ohio State University, Columbus, OH 43210, U.S.A
| | - Jonathan M Jacobs
- Department of Plant Pathology, The Ohio State University, Columbus, OH 43210, U.S.A
- Infectious Diseases Institute, The Ohio State University, Columbus, OH 43210, U.S.A
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12
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Liu Z, Friskop A, Jacobs JM, Dill-Macky R. Bacterial Leaf Streak: A Persistent and Increasingly Important Disease Problem for Cereal Crops. PHYTOPATHOLOGY 2023; 113:2020-2023. [PMID: 38015599 DOI: 10.1094/phyto-11-23-0423-sa] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Affiliation(s)
- Zhaohui Liu
- Department of Plant Pathology, North Dakota State University, Fargo, ND, 58108
| | - Andrew Friskop
- Department of Plant Pathology, North Dakota State University, Fargo, ND, 58108
| | - Jonathan M Jacobs
- Department of Plant Pathology, The Ohio State University, Columbus, OH 43210
- Infectious Diseases Institute, The Ohio State University, Columbus, OH 43210
| | - Ruth Dill-Macky
- Department of Plant Pathology, University of Minnesota, St. Paul, MN 55108
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13
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Zhao M, Peng Z, Qin Y, Tamang TM, Zhang L, Tian B, Chen Y, Liu Y, Zhang J, Lin G, Zheng H, He C, Lv K, Klaus A, Marcon C, Hochholdinger F, Trick HN, Liu Y, Cho MJ, Park S, Wei H, Zheng J, White FF, Liu S. Bacterium-enabled transient gene activation by artificial transcription factors for resolving gene regulation in maize. THE PLANT CELL 2023; 35:2736-2749. [PMID: 37233025 PMCID: PMC10396389 DOI: 10.1093/plcell/koad155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 04/11/2023] [Accepted: 05/04/2023] [Indexed: 05/27/2023]
Abstract
Understanding gene regulatory networks is essential to elucidate developmental processes and environmental responses. Here, we studied regulation of a maize (Zea mays) transcription factor gene using designer transcription activator-like effectors (dTALes), which are synthetic Type III TALes of the bacterial genus Xanthomonas and serve as inducers of disease susceptibility gene transcription in host cells. The maize pathogen Xanthomonas vasicola pv. vasculorum was used to introduce 2 independent dTALes into maize cells to induced expression of the gene glossy3 (gl3), which encodes a MYB transcription factor involved in biosynthesis of cuticular wax. RNA-seq analysis of leaf samples identified, in addition to gl3, 146 genes altered in expression by the 2 dTALes. Nine of the 10 genes known to be involved in cuticular wax biosynthesis were upregulated by at least 1 of the 2 dTALes. A gene previously unknown to be associated with gl3, Zm00001d017418, which encodes aldehyde dehydrogenase, was also expressed in a dTALe-dependent manner. A chemically induced mutant and a CRISPR-Cas9 mutant of Zm00001d017418 both exhibited glossy leaf phenotypes, indicating that Zm00001d017418 is involved in biosynthesis of cuticular waxes. Bacterial protein delivery of dTALes proved to be a straightforward and practical approach for the analysis and discovery of pathway-specific genes in maize.
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Affiliation(s)
- Mingxia Zhao
- Department of Plant Pathology, Kansas State University, Manhattan, KS 66506, USA
| | - Zhao Peng
- Department of Plant Pathology, University of Florida, Gainesville, FL 32611, USA
- College of Plant Protection, Jilin Agricultural University, Changchun, Jilin 130118, China
| | - Yang Qin
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Tej Man Tamang
- Department of Plant Pathology, Kansas State University, Manhattan, KS 66506, USA
| | - Ling Zhang
- College of Forest Resources and Environmental Science, Michigan Technological University, Houghton, MI 49931, USA
| | - Bin Tian
- Department of Plant Pathology, Kansas State University, Manhattan, KS 66506, USA
| | - Yueying Chen
- Department of Plant Pathology, Kansas State University, Manhattan, KS 66506, USA
| | - Yan Liu
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Junli Zhang
- Department of Plant Pathology, University of Florida, Gainesville, FL 32611, USA
| | - Guifang Lin
- Department of Plant Pathology, Kansas State University, Manhattan, KS 66506, USA
| | - Huakun Zheng
- Department of Plant Pathology, Kansas State University, Manhattan, KS 66506, USA
| | - Cheng He
- Department of Plant Pathology, Kansas State University, Manhattan, KS 66506, USA
| | - Kaiwen Lv
- State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Heilongjiang 150040, China
| | - Alina Klaus
- INRES, Institute of Crop Science and Resource Conservation, Crop Functional Genomics, University of Bonn, Bonn 53113, Germany
| | - Caroline Marcon
- INRES, Institute of Crop Science and Resource Conservation, Crop Functional Genomics, University of Bonn, Bonn 53113, Germany
| | - Frank Hochholdinger
- INRES, Institute of Crop Science and Resource Conservation, Crop Functional Genomics, University of Bonn, Bonn 53113, Germany
| | - Harold N Trick
- Department of Plant Pathology, Kansas State University, Manhattan, KS 66506, USA
| | - Yunjun Liu
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Myeong-Je Cho
- Innovative Genomics Institute, University of California, Berkeley, CA 94704, USA
| | - Sunghun Park
- Department of Horticulture and Natural Resources, Kansas State University, Manhattan, KS 66506, USA
| | - Hairong Wei
- College of Forest Resources and Environmental Science, Michigan Technological University, Houghton, MI 49931, USA
| | - Jun Zheng
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Frank F White
- Department of Plant Pathology, University of Florida, Gainesville, FL 32611, USA
| | - Sanzhen Liu
- Department of Plant Pathology, Kansas State University, Manhattan, KS 66506, USA
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14
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de Souza-Neto RR, Vasconcelos FNDC, Teper D, Carvalho IGB, Takita MA, Benedetti CE, Wang N, de Souza AA. The Expansin Gene CsLIEXP1 Is a Direct Target of CsLOB1 in Citrus. PHYTOPATHOLOGY 2023; 113:1266-1277. [PMID: 36825333 DOI: 10.1094/phyto-11-22-0424-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: 06/18/2023]
Abstract
Transcription activator-like effectors are key virulence factors of Xanthomonas. They are secreted into host plant cells and mimic transcription factors inducing the expression of host susceptibility (S) genes. In citrus, CsLOB1 is a direct target of PthA4, the primary effector associated with citrus canker symptoms. CsLOB1 is a transcription factor, and its expression is required for canker symptoms induced by Xanthomonas citri subsp. citri. Several genes are up-regulated by PthA4; however, only CsLOB1 was described as an S gene induced by PthA4. Here, we investigated whether other up-regulated genes could be direct targets of PthA4 or CsLOB1. Seven up-regulated genes by PthA4 were investigated; however, an expansin-coding gene was more induced than CsLOB1. In Nicotiana benthamiana transient expression experiments, we demonstrate that the expansin-coding gene, referred here to as CsLOB1-INDUCED EXPANSIN 1 (CsLIEXP1), is not a direct target of PthA4, but CsLOB1. Interestingly, CsLIEXP1 was induced by CsLOB1 even without the predicted CsLOB1 binding site, which suggested that CsLOB1 has other unknown binding sites. We also investigated the minimum promoter regulated by CsLOB1, and this region and LOB1 domain were conserved among citrus species and relatives, which suggests that the interaction PthA4-CsLOB1-CsLIEXP1 is conserved in citrus species and relatives. This is the first study that experimentally demonstrated a CsLOB1 downstream target and lays the foundation to identify other new targets. In addition, we demonstrated that the CsLIEXP1 is a putative S gene indirectly induced by PthA4, which may serve as the target for genome editing to generate citrus canker-resistant varieties.
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Affiliation(s)
- Reinaldo Rodrigues de Souza-Neto
- Citrus Research Center "Sylvio Moreira", Agronomic Institute-IAC, Brazil
- Departament of Genetics, Evolution and Bioagents, Institute of Biology, University of Campinas, Brazil
| | | | - Doron Teper
- Department of Plant Pathology and Weed Research, Institute of Plant Protection, Agricultural Research Organization, Volcani Center, Israel
| | | | | | - Celso Eduardo Benedetti
- Brazilian Biosciences National Laboratory (LNBio), Brazilian Center for Research in Energy and Materials (CNPEM), Brazil
| | - Nian Wang
- Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences (IFAS), University of Florida, U.S.A
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15
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Teper D, White FF, Wang N. The Dynamic Transcription Activator-Like Effector Family of Xanthomonas. PHYTOPATHOLOGY 2023; 113:651-666. [PMID: 36449529 DOI: 10.1094/phyto-10-22-0365-kd] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Transcription activator-like effectors (TALEs) are bacterial proteins that are injected into the eukaryotic nucleus to act as transcriptional factors and function as key virulence factors of the phytopathogen Xanthomonas. TALEs are translocated into plant host cells via the type III secretion system and induce the expression of host susceptibility (S) genes to facilitate disease. The unique modular DNA binding domains of TALEs comprise an array of nearly identical direct repeats that enable binding to DNA targets based on the recognition of a single nucleotide target per repeat. The very nature of TALE structure and function permits the proliferation of TALE genes and evolutionary adaptations in the host to counter TALE function, making the TALE-host interaction the most dynamic story in effector biology. The TALE genes appear to be a relatively young effector gene family, with a presence in all virulent members of some species and absent in others. Genome sequencing has revealed many TALE genes throughout the xanthomonads, and relatively few have been associated with a cognate S gene. Several species, including Xanthomonas oryzae pv. oryzae and X. citri pv. citri, have near absolute requirement for TALE gene function, while the genes appear to be just now entering the disease interactions with new fitness contributions to the pathogens of tomato and pepper among others. Deciphering the simple and effective DNA binding mechanism also has led to the development of DNA manipulation tools in fields of gene editing and transgenic research. In the three decades since their discovery, TALE research remains at the forefront of the study of bacterial evolution, plant-pathogen interactions, and synthetic biology. We also discuss critical questions that remain to be addressed regarding TALEs.
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Affiliation(s)
- Doron Teper
- Department of Plant Pathology and Weed Research, Agricultural Research Organization, Volcani Institute, Rishon LeZion, Israel
| | - Frank F White
- Department of Plant Pathology, Institute of Food and Agricultural Sciences (IFAS), University of Florida, Gainesville, FL, U.S.A
| | - Nian Wang
- Citrus Research and Education Center, Department of Microbiology and Cell Science, IFAS, University of Florida, Lake Alfred, FL, U.S.A
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16
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Light prevents pathogen-induced aqueous microenvironments via potentiation of salicylic acid signaling. Nat Commun 2023; 14:713. [PMID: 36759607 PMCID: PMC9911384 DOI: 10.1038/s41467-023-36382-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Accepted: 01/30/2023] [Indexed: 02/11/2023] Open
Abstract
Many plant pathogens induce water-soaked lesions in infected tissues. In the case of Pseudomonas syringae (Pst), water-soaking effectors stimulate abscisic acid (ABA) production and signaling, resulting in stomatal closure. This reduces transpiration, increases water accumulation, and induces an apoplastic microenvironment favorable for bacterial growth. Stomata are sensitive to environmental conditions, including light. Here, we show that a period of darkness is required for water-soaking, and that a constant light regime abrogates stomatal closure by Pst. We find that constant light induces resistance to Pst, and that this effect requires salicylic acid (SA). Constant light did not alter effector-induced accumulation of ABA, but induced greater SA production, promoting stomatal opening despite the presence of ABA. Furthermore, application of a SA analog was sufficient to prevent pathogen-induced stomatal closure and water-soaking. Our results suggest potential approaches for interfering with a common virulence strategy, as well as providing a physiological mechanism by which SA functions in defense against pathogens.
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17
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You Y, Koczyk G, Nuc M, Morbitzer R, Holmes DR, von Roepenack-Lahaye E, Hou S, Giudicatti A, Gris C, Manavella PA, Noël LD, Krajewski P, Lahaye T. The eINTACT system dissects bacterial exploitation of plant osmosignalling to enhance virulence. NATURE PLANTS 2023; 9:128-141. [PMID: 36550363 PMCID: PMC9873569 DOI: 10.1038/s41477-022-01302-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 10/28/2022] [Indexed: 06/17/2023]
Abstract
Bacteria inject effector proteins into host cells to manipulate cellular processes that promote disease. Since bacteria deliver minuscule amounts of effectors only into targeted host cells, it is technically challenging to capture effector-dependent cellular changes from bulk-infected host tissues. Here, we report a new technique called effector-inducible isolation of nuclei tagged in specific cell types (eINTACT), which facilitates affinity-based purification of nuclei from Arabidopsis plant cells that have received Xanthomonas bacterial effectors. Analysis of purified nuclei reveals that the Xanthomonas effector XopD manipulates the expression of Arabidopsis abscisic acid signalling-related genes and activates OSCA1.1, a gene encoding a calcium-permeable channel required for stomatal closure in response to osmotic stress. The loss of OSCA1.1 causes leaf wilting and reduced bacterial growth in infected leaves, suggesting that OSCA1.1 promotes host susceptibility. eINTACT allows us to uncover that XopD exploits host OSCA1.1/abscisic acid osmosignalling-mediated stomatal closure to create a humid habitat that favours bacterial growth and opens up a new avenue for accurately elucidating functions of effectors from numerous gram-negative plant bacteria in native infection contexts.
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Affiliation(s)
- Yuan You
- Department of General Genetics, Center for Plant Molecular Biology (ZMBP), Eberhard-Karls-University Tübingen, Tübingen, Germany.
| | - Grzegorz Koczyk
- Department of Biometry and Bioinformatics, Institute of Plant Genetics, Polish Academy of Sciences, Poznań, Poland
| | - Maria Nuc
- Department of Biometry and Bioinformatics, Institute of Plant Genetics, Polish Academy of Sciences, Poznań, Poland
| | - Robert Morbitzer
- Department of General Genetics, Center for Plant Molecular Biology (ZMBP), Eberhard-Karls-University Tübingen, Tübingen, Germany
| | - Danalyn R Holmes
- Department of General Genetics, Center for Plant Molecular Biology (ZMBP), Eberhard-Karls-University Tübingen, Tübingen, Germany
| | | | - Shiji Hou
- State Key Laboratory of Agricultural Microbiology, Hubei Key Lab of Plant Pathology, Hubei Hongshan Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, PR of China
| | - Axel Giudicatti
- Instituto de Agrobiotecnología del Litoral (CONICET-UNL), Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Santa Fe, Argentina
| | - Carine Gris
- Laboratoire des Interactions Plantes-Microbes-Environnement (LIPME), Université de Toulouse, INRAE, CNRS, Castanet-Tolosan, France
| | - Pablo A Manavella
- Instituto de Agrobiotecnología del Litoral (CONICET-UNL), Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Santa Fe, Argentina
| | - Laurent D Noël
- Laboratoire des Interactions Plantes-Microbes-Environnement (LIPME), Université de Toulouse, INRAE, CNRS, Castanet-Tolosan, France
| | - Paweł Krajewski
- Department of Biometry and Bioinformatics, Institute of Plant Genetics, Polish Academy of Sciences, Poznań, Poland
| | - Thomas Lahaye
- Department of General Genetics, Center for Plant Molecular Biology (ZMBP), Eberhard-Karls-University Tübingen, Tübingen, Germany
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18
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Lu Y, Zhong Q, Xiao S, Wang B, Ke X, Zhang Y, Yin F, Zhang D, Jiang C, Liu L, Li J, Yu T, Wang L, Cheng Z, Chen L. A new NLR disease resistance gene Xa47 confers durable and broad-spectrum resistance to bacterial blight in rice. FRONTIERS IN PLANT SCIENCE 2022; 13:1037901. [PMID: 36507384 PMCID: PMC9730417 DOI: 10.3389/fpls.2022.1037901] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Accepted: 10/31/2022] [Indexed: 06/01/2023]
Abstract
Bacterial blight (BB) induced by Xanthomonas oryzae pv. oryzae (Xoo) is a devastating bacterial disease in rice. The use of disease resistance (R) genes is the most efficient method to control BB. Members of the nucleotide-binding domain and leucine-rich repeat containing protein (NLR) family have significant roles in plant defense. In this study, Xa47, a new bacterial blight R gene encoding a typical NLR, was isolated from G252 rice material, and XA47 was localized in the nucleus and cytoplasm. Among 180 rice materials tested, Xa47 was discovered in certain BB-resistant materials. Compared with the wild-type G252, the knockout mutants of Xa47 was more susceptible to Xoo. By contrast, overexpression of Xa47 in the susceptible rice material JG30 increased BB resistance. The findings indicate that Xa47 positively regulates the Xoo stress response. Consequently, Xa47 may have application potential in the genetic improvement of plant disease resistance. The molecular mechanism of Xa47 regulation merits additional examination.
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Affiliation(s)
- Yuanda Lu
- Biotechnology and Germplasm Resources Institute, Yunnan Academy of Agricultural Sciences, Yunnan Provincial Key Lab of Agricultural Biotechnology, Kunming, China
- College of Plant Protection, Yunnan Agricultural University, Kunming, China
| | - Qiaofang Zhong
- Biotechnology and Germplasm Resources Institute, Yunnan Academy of Agricultural Sciences, Yunnan Provincial Key Lab of Agricultural Biotechnology, Kunming, China
| | - Suqin Xiao
- Biotechnology and Germplasm Resources Institute, Yunnan Academy of Agricultural Sciences, Yunnan Provincial Key Lab of Agricultural Biotechnology, Kunming, China
| | - Bo Wang
- Biotechnology and Germplasm Resources Institute, Yunnan Academy of Agricultural Sciences, Yunnan Provincial Key Lab of Agricultural Biotechnology, Kunming, China
| | - Xue Ke
- Biotechnology and Germplasm Resources Institute, Yunnan Academy of Agricultural Sciences, Yunnan Provincial Key Lab of Agricultural Biotechnology, Kunming, China
| | - Yun Zhang
- Biotechnology and Germplasm Resources Institute, Yunnan Academy of Agricultural Sciences, Yunnan Provincial Key Lab of Agricultural Biotechnology, Kunming, China
| | - Fuyou Yin
- Biotechnology and Germplasm Resources Institute, Yunnan Academy of Agricultural Sciences, Yunnan Provincial Key Lab of Agricultural Biotechnology, Kunming, China
| | - Dunyu Zhang
- Biotechnology and Germplasm Resources Institute, Yunnan Academy of Agricultural Sciences, Yunnan Provincial Key Lab of Agricultural Biotechnology, Kunming, China
| | - Cong Jiang
- Biotechnology and Germplasm Resources Institute, Yunnan Academy of Agricultural Sciences, Yunnan Provincial Key Lab of Agricultural Biotechnology, Kunming, China
| | - Li Liu
- Biotechnology and Germplasm Resources Institute, Yunnan Academy of Agricultural Sciences, Yunnan Provincial Key Lab of Agricultural Biotechnology, Kunming, China
| | - Jinlu Li
- Biotechnology and Germplasm Resources Institute, Yunnan Academy of Agricultural Sciences, Yunnan Provincial Key Lab of Agricultural Biotechnology, Kunming, China
| | - Tengqiong Yu
- Biotechnology and Germplasm Resources Institute, Yunnan Academy of Agricultural Sciences, Yunnan Provincial Key Lab of Agricultural Biotechnology, Kunming, China
| | - Lingxian Wang
- Biotechnology and Germplasm Resources Institute, Yunnan Academy of Agricultural Sciences, Yunnan Provincial Key Lab of Agricultural Biotechnology, Kunming, China
| | - Zaiquan Cheng
- Biotechnology and Germplasm Resources Institute, Yunnan Academy of Agricultural Sciences, Yunnan Provincial Key Lab of Agricultural Biotechnology, Kunming, China
| | - Ling Chen
- Biotechnology and Germplasm Resources Institute, Yunnan Academy of Agricultural Sciences, Yunnan Provincial Key Lab of Agricultural Biotechnology, Kunming, China
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19
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Todd JNA, Carreón-Anguiano KG, Islas-Flores I, Canto-Canché B. Microbial Effectors: Key Determinants in Plant Health and Disease. Microorganisms 2022; 10:1980. [PMID: 36296254 PMCID: PMC9610748 DOI: 10.3390/microorganisms10101980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 09/27/2022] [Accepted: 09/29/2022] [Indexed: 11/17/2022] Open
Abstract
Effectors are small, secreted molecules that alter host cell structure and function, thereby facilitating infection or triggering a defense response. Effectoromics studies have focused on effectors in plant-pathogen interactions, where their contributions to virulence are determined in the plant host, i.e., whether the effector induces resistance or susceptibility to plant disease. Effector molecules from plant pathogenic microorganisms such as fungi, oomycetes and bacteria are major disease determinants. Interestingly, the effectors of non-pathogenic plant organisms such as endophytes display similar functions but have different outcomes for plant health. Endophyte effectors commonly aid in the establishment of mutualistic interactions with the plant and contribute to plant health through the induction of systemic resistance against pathogens, while pathogenic effectors mainly debilitate the plant's immune response, resulting in the establishment of disease. Effectors of plant pathogens as well as plant endophytes are tools to be considered in effectoromics for the development of novel strategies for disease management. This review aims to present effectors in their roles as promotors of health or disease for the plant host.
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Affiliation(s)
- Jewel Nicole Anna Todd
- Unidad de Biotecnología, Centro de Investigación Científica de Yucatán, A.C., Calle 43 No. 130 x 32 y 34, Colonia Chuburná de Hidalgo, Mérida C.P. 97205, Yucatán, Mexico
| | - Karla Gisel Carreón-Anguiano
- Unidad de Biotecnología, Centro de Investigación Científica de Yucatán, A.C., Calle 43 No. 130 x 32 y 34, Colonia Chuburná de Hidalgo, Mérida C.P. 97205, Yucatán, Mexico
| | - Ignacio Islas-Flores
- Unidad de Bioquímica y Biología Molecular de Plantas, Centro de Investigación Científica de Yucatán, A.C., Calle 43 No. 130 x 32 y 34, Colonia Chuburná de Hidalgo, Mérida C.P. 97205, Yucatán, Mexico
| | - Blondy Canto-Canché
- Unidad de Biotecnología, Centro de Investigación Científica de Yucatán, A.C., Calle 43 No. 130 x 32 y 34, Colonia Chuburná de Hidalgo, Mérida C.P. 97205, Yucatán, Mexico
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20
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Clavijo F, Barrera C, Benčič A, Croce V, Jacobs JM, Bernal AJ, Koebnik R, Roman-Reyna V. Complete Genome Sequence Resource for Xanthomonas translucens pv. undulosa MAI5034, a Wheat Pathogen from Uruguay. PHYTOPATHOLOGY 2022; 112:2036-2039. [PMID: 35559654 DOI: 10.1094/phyto-01-22-0025-a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Affiliation(s)
- Felipe Clavijo
- Laboratorio de Microbiología Molecular, Departamento de Biociencias, Facultad de Química, Universidad de la República, Montevideo, Uruguay
| | - Claudia Barrera
- Department of Biological Sciences, Universidad de Los Andes, Bogotá, Colombia
| | - Aleksander Benčič
- National Institute of Biology, Ljubljana, Slovenia
- Jožef Stefan International Postgraduate School, Ljubljana, Slovenia
| | - Valentina Croce
- Laboratorio de Microbiología Molecular, Departamento de Biociencias, Facultad de Química, Universidad de la República, Montevideo, Uruguay
| | - Jonathan M Jacobs
- Department of Plant Pathology, The Ohio State University, Columbus, OH, U.S.A
- Infectious Diseases Institute, The Ohio State University, Columbus, OH, U.S.A
| | - Adriana J Bernal
- Department of Biological Sciences, Universidad de Los Andes, Bogotá, Colombia
| | - Ralf Koebnik
- Plant Health Institute of Montpellier, University of Montpellier, CIRAD, INRAE, Institut Agro, IRD, Montpellier, France
| | - Veronica Roman-Reyna
- Department of Plant Pathology, The Ohio State University, Columbus, OH, U.S.A
- Infectious Diseases Institute, The Ohio State University, Columbus, OH, U.S.A
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21
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Zang S, Qin L, Zhao Z, Zhang J, Zou W, Wang D, Feng A, Yang S, Que Y, Su Y. Characterization and Functional Implications of the Nonexpressor of Pathogenesis-Related Genes 1 (NPR1) in Saccharum. Int J Mol Sci 2022; 23:ijms23147984. [PMID: 35887330 PMCID: PMC9317693 DOI: 10.3390/ijms23147984] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 07/13/2022] [Accepted: 07/18/2022] [Indexed: 11/16/2022] Open
Abstract
Sugarcane (Saccharum spp.) is an important sugar and energy crop worldwide. As a core regulator of the salicylic acid (SA) signaling pathway, nonexpressor of pathogenesis-related genes 1 (NPR1) plays a significant role in the response of the plant to biotic and abiotic stresses. However, there is currently no report on the NPR1-like gene family in sugarcane. In this study, a total of 18 NPR1-like genes were identified in Saccharum spontaneum and classified into three clades (clade I, II, and III). The cis-elements predicted in the promotors revealed that the sugarcane NPR1-like genes may be involved in various phytohormones and stress responses. RNA sequencing and quantitative real-time PCR analysis demonstrated that NPR1-like genes were differentially expressed in sugarcane tissues and under Sporisorium scitamineum stress. In addition, a novel ShNPR1 gene from Saccharum spp. hybrid ROC22 was isolated by homologous cloning and validated to be a nuclear-localized clade II member. The ShNPR1 gene was constitutively expressed in all the sugarcane tissues, with the highest expression level in the leaf and the lowest in the bud. The expression level of ShNPR1 was decreased by the plant hormones salicylic acid (SA) and abscisic acid (ABA). Additionally, the transient expression showed that the ShNPR1 gene plays a positive role in Nicotiana benthamiana plants’ defense response to Ralstonia solanacearum and Fusarium solani var. coeruleum. This study provided comprehensive information for the NPR1-like family in sugarcane, which should be helpful for functional characterization of sugarcane NPR1-like genes in the future.
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Affiliation(s)
- Shoujian Zang
- Key Laboratory of Sugarcane Biology and Genetic Breeding, Ministry of Agriculture and Rural Affairs, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (S.Z.); (L.Q.); (Z.Z.); (J.Z.); (W.Z.); (D.W.); (A.F.); (S.Y.)
| | - Liqian Qin
- Key Laboratory of Sugarcane Biology and Genetic Breeding, Ministry of Agriculture and Rural Affairs, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (S.Z.); (L.Q.); (Z.Z.); (J.Z.); (W.Z.); (D.W.); (A.F.); (S.Y.)
| | - Zhennan Zhao
- Key Laboratory of Sugarcane Biology and Genetic Breeding, Ministry of Agriculture and Rural Affairs, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (S.Z.); (L.Q.); (Z.Z.); (J.Z.); (W.Z.); (D.W.); (A.F.); (S.Y.)
| | - Jing Zhang
- Key Laboratory of Sugarcane Biology and Genetic Breeding, Ministry of Agriculture and Rural Affairs, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (S.Z.); (L.Q.); (Z.Z.); (J.Z.); (W.Z.); (D.W.); (A.F.); (S.Y.)
| | - Wenhui Zou
- Key Laboratory of Sugarcane Biology and Genetic Breeding, Ministry of Agriculture and Rural Affairs, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (S.Z.); (L.Q.); (Z.Z.); (J.Z.); (W.Z.); (D.W.); (A.F.); (S.Y.)
| | - Dongjiao Wang
- Key Laboratory of Sugarcane Biology and Genetic Breeding, Ministry of Agriculture and Rural Affairs, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (S.Z.); (L.Q.); (Z.Z.); (J.Z.); (W.Z.); (D.W.); (A.F.); (S.Y.)
| | - Aoyin Feng
- Key Laboratory of Sugarcane Biology and Genetic Breeding, Ministry of Agriculture and Rural Affairs, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (S.Z.); (L.Q.); (Z.Z.); (J.Z.); (W.Z.); (D.W.); (A.F.); (S.Y.)
| | - Shaolin Yang
- Key Laboratory of Sugarcane Biology and Genetic Breeding, Ministry of Agriculture and Rural Affairs, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (S.Z.); (L.Q.); (Z.Z.); (J.Z.); (W.Z.); (D.W.); (A.F.); (S.Y.)
- Yunnan Key Laboratory of Sugarcane Genetic Improvement, Sugarcane Research Institute, Yunnan Academy of Agricultural Sciences, Kaiyuan 661600, China
| | - Youxiong Que
- Key Laboratory of Sugarcane Biology and Genetic Breeding, Ministry of Agriculture and Rural Affairs, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (S.Z.); (L.Q.); (Z.Z.); (J.Z.); (W.Z.); (D.W.); (A.F.); (S.Y.)
- Key Laboratory of Genetics, Breeding and Multiple Utilization of Crops, Ministry of Education, College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- Correspondence: (Y.Q.); (Y.S.); Tel.: +86-591-8385-2547 (Y.Q. & Y.S.)
| | - Yachun Su
- Key Laboratory of Sugarcane Biology and Genetic Breeding, Ministry of Agriculture and Rural Affairs, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (S.Z.); (L.Q.); (Z.Z.); (J.Z.); (W.Z.); (D.W.); (A.F.); (S.Y.)
- Key Laboratory of Genetics, Breeding and Multiple Utilization of Crops, Ministry of Education, College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- Correspondence: (Y.Q.); (Y.S.); Tel.: +86-591-8385-2547 (Y.Q. & Y.S.)
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22
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Zhang B, Han X, Yuan W, Zhang H. TALEs as double-edged swords in plant-pathogen interactions: Progress, challenges, and perspectives. PLANT COMMUNICATIONS 2022; 3:100318. [PMID: 35576155 PMCID: PMC9251431 DOI: 10.1016/j.xplc.2022.100318] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 03/08/2022] [Accepted: 03/23/2022] [Indexed: 06/15/2023]
Abstract
Xanthomonas species colonize many host plants and cause huge losses worldwide. Transcription activator-like effectors (TALEs) are secreted by Xanthomonas and translocated into host cells to manipulate the expression of target genes, especially by Xanthomonas oryzae pv. oryzae and Xanthomonas oryzae pv. oryzicola, which cause bacterial blight and bacterial leaf streak, respectively, in rice. In this review, we summarize the progress of studies on the interaction between Xanthomonas and hosts, covering both rice and other plants. TALEs are not only key factors that make plants susceptible but are also essential components of plant resistance. Characterization of TALEs and TALE-like proteins has improved our understanding of TALE evolution and promoted the development of gene editing tools. In addition, the interactions between TALEs and hosts have also provided strategies and possibilities for genetic engineering in crop improvement.
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Affiliation(s)
- Biaoming Zhang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan 430062, China
| | - Xiaoyuan Han
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan 430062, China
| | - Wenya Yuan
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan 430062, China.
| | - Haitao Zhang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan 430062, China.
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23
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Cowles KN, Block AK, Barak JD. Xanthomonas hortorum pv. gardneri TAL effector AvrHah1 is necessary and sufficient for increased persistence of Salmonella enterica on tomato leaves. Sci Rep 2022; 12:7313. [PMID: 35508535 PMCID: PMC9068798 DOI: 10.1038/s41598-022-11456-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 04/25/2022] [Indexed: 01/16/2023] Open
Abstract
Salmonella enterica is ubiquitous in the plant environment, persisting in the face of UV stress, plant defense responses, desiccation, and nutrient limitation. These fluctuating conditions of the leaf surface result in S. enterica population decline. Biomultipliers, such as the phytopathogenic bacterium Xanthomonas hortorum pv. gardneri (Xhg), alter the phyllosphere to the benefit of S. enterica. Specific Xhg-dependent changes to this niche that promote S. enterica persistence remain unclear, and this work focuses on identifying factors that lead to increased S. enterica survival on leaves. Here, we show that the Xhg transcription activator-like effector AvrHah1 is both necessary and sufficient for increased survival of S. enterica on tomato leaves. An Xhg avrHah1 mutant fails to influence S. enterica survival while addition of avrHah1 to X. vesicatoria provides a gain of function. Our results indicate that although Xhg stimulates a robust immune response from the plant, AvrHah1 is not required for these effects. In addition, we demonstrate that cellular leakage that occurs during disease is independent of AvrHah1. Investigation of the interaction between S. enterica, Xhg, and the plant host provides information regarding how an inhospitable environment changes during infection and can be transformed into a habitable niche.
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Affiliation(s)
- Kimberly N Cowles
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI, USA
| | - Anna K Block
- Center for Medical, Agricultural, and Veterinary Entomology, U.S. Department of Agriculture-Agricultural Research Service, Gainesville, FL, USA
| | - Jeri D Barak
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI, USA.
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24
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Hu Y, Ding Y, Cai B, Qin X, Wu J, Yuan M, Wan S, Zhao Y, Xin XF. Bacterial effectors manipulate plant abscisic acid signaling for creation of an aqueous apoplast. Cell Host Microbe 2022; 30:518-529.e6. [PMID: 35247331 DOI: 10.1016/j.chom.2022.02.002] [Citation(s) in RCA: 47] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 12/05/2021] [Accepted: 02/02/2022] [Indexed: 01/23/2023]
Abstract
Phytopathogens like Pseudomonas syringae induce "water soaking" in the apoplastic space of plant leaf tissue as a key virulence mechanism. Water soaking is commonly observed in diverse pathosystems, yet the underlying physiological basis remains largely elusive. Here, we show that one of the strong P. syringae water-soaking inducers, AvrE, alters the regulation of abscisic acid (ABA) to induce ABA signaling, stomatal closure, and, thus, water soaking. AvrE binds and inhibits the function of Arabidopsis type one protein phosphatases (TOPPs), which negatively regulate ABA by suppressing SnRK2s, a key node of the ABA signaling pathway. The topp12537 quintuple mutants display significantly enhanced water soaking after P. syringae inoculation, whereas the loss of the ABA pathway dampens P. syringae-induced water soaking and disease. Our study uncovers the hijacking of ABA signaling and stomatal closure by P. syringae effectors as key mechanisms of disease susceptibility.
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Affiliation(s)
- Yezhou Hu
- National key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China; University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Yanxia Ding
- National key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China; University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Boying Cai
- National key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China; University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaohui Qin
- Shanghai Center for Plant Stress Biology and CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Jingni Wu
- National key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
| | - Minhang Yuan
- National key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China; University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Shiwei Wan
- National key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
| | - Yang Zhao
- Shanghai Center for Plant Stress Biology and CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Xiu-Fang Xin
- National key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China; University of the Chinese Academy of Sciences, Beijing 100049, China; Chinese Academy of Sciences (CAS) and John Innes Centre, Centre of Excellence for Plant and Microbial Sciences, Shanghai 200032, China.
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25
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Roussin-Léveillée C, Lajeunesse G, St-Amand M, Veerapen VP, Silva-Martins G, Nomura K, Brassard S, Bolaji A, He SY, Moffett P. Evolutionarily conserved bacterial effectors hijack abscisic acid signaling to induce an aqueous environment in the apoplast. Cell Host Microbe 2022; 30:489-501.e4. [PMID: 35247330 PMCID: PMC9012689 DOI: 10.1016/j.chom.2022.02.006] [Citation(s) in RCA: 39] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 12/04/2021] [Accepted: 02/08/2022] [Indexed: 11/26/2022]
Abstract
High atmospheric humidity levels profoundly impact host-pathogen interactions in plants by enabling the establishment of an aqueous living space that benefits pathogens. The effectors HopM1 and AvrE1 of the bacterial pathogen Pseudomonas syringae have been shown to induce an aqueous apoplast under such conditions. However, the mechanisms by which this happens remain unknown. Here, we show that HopM1 and AvrE1 work redundantly to establish an aqueous living space by inducing a major reprogramming of the Arabidopsis thaliana transcriptome landscape. These effectors induce a strong abscisic acid (ABA) signature, which promotes stomatal closure, resulting in reduced leaf transpiration and water-soaking lesions. Furthermore, these effectors preferentially increase ABA accumulation in guard cells, which control stomatal aperture. Notably, a guard-cell-specific ABA transporter, ABCG40, is necessary for HopM1 induction of water-soaking lesions. This study provides molecular insights into a chain of events of stomatal manipulation that create an ideal microenvironment to facilitate infection.
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Affiliation(s)
| | - Gaële Lajeunesse
- Centre SÈVE, Département de Biologie, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Méliane St-Amand
- Centre SÈVE, Département de Biologie, Université de Sherbrooke, Sherbrooke, QC, Canada
| | | | | | - Kinya Nomura
- Department of Energy, Plant Research Laboratory, Michigan State University, East Lansing, MI, USA; Department of Biology, Duke University, Durham, NC, USA; Howard Hughes Medical Institute, Durham, NC, USA
| | - Sandrine Brassard
- Centre SÈVE, Département de Biologie, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Ayooluwa Bolaji
- Centre SÈVE, Département de Biologie, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Sheng Yang He
- Department of Energy, Plant Research Laboratory, Michigan State University, East Lansing, MI, USA; Department of Biology, Duke University, Durham, NC, USA; Howard Hughes Medical Institute, Durham, NC, USA
| | - Peter Moffett
- Centre SÈVE, Département de Biologie, Université de Sherbrooke, Sherbrooke, QC, Canada.
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26
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Goettelmann F, Roman-Reyna V, Cunnac S, Jacobs JM, Bragard C, Studer B, Koebnik R, Kölliker R. Complete Genome Assemblies of All Xanthomonas translucens Pathotype Strains Reveal Three Genetically Distinct Clades. Front Microbiol 2022; 12:817815. [PMID: 35310401 PMCID: PMC8924669 DOI: 10.3389/fmicb.2021.817815] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 12/29/2021] [Indexed: 11/13/2022] Open
Abstract
The Xanthomonas translucens species comprises phytopathogenic bacteria that can cause serious damage to cereals and to forage grasses. So far, the genomic resources for X. translucens were limited, which hindered further understanding of the host–pathogen interactions at the molecular level and the development of disease-resistant cultivars. To this end, we complemented the available complete genome sequence of the X. translucens pv. translucens pathotype strain DSM 18974 by sequencing the genomes of all the other 10 X. translucens pathotype strains using PacBio long-read technology and assembled complete genome sequences. Phylogeny based on average nucleotide identity (ANI) revealed three distinct clades within the species, which we propose to classify as clades Xt-I, Xt-II, and Xt-III. In addition to 2,181 core X. translucens genes, a total of 190, 588, and 168 genes were found to be exclusive to each clade, respectively. Moreover, 29 non-transcription activator-like effector (TALE) and 21 TALE type III effector classes were found, and clade- or strain-specific effectors were identified. Further investigation of these genes could help to identify genes that are critically involved in pathogenicity and/or host adaptation, setting the grounds for the development of new resistant cultivars.
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Affiliation(s)
- Florian Goettelmann
- Molecular Plant Breeding, Institute of Agricultural Sciences, ETH Zürich, Zurich, Switzerland
| | - Veronica Roman-Reyna
- Department of Plant Pathology, The Ohio State University, Columbus, OH, United States.,Infectious Diseases Institute, The Ohio State University, Columbus, OH, United States
| | - Sébastien Cunnac
- Plant Health Institute of Montpellier, University of Montpellier, CIRAD, INRAE, Institut Agro, IRD, Montpellier, France
| | - Jonathan M Jacobs
- Department of Plant Pathology, The Ohio State University, Columbus, OH, United States.,Infectious Diseases Institute, The Ohio State University, Columbus, OH, United States
| | - Claude Bragard
- Earth and Life Institute, UCLouvain, Louvain-la-Neuve, Belgium
| | - Bruno Studer
- Molecular Plant Breeding, Institute of Agricultural Sciences, ETH Zürich, Zurich, Switzerland
| | - Ralf Koebnik
- Plant Health Institute of Montpellier, University of Montpellier, CIRAD, INRAE, Institut Agro, IRD, Montpellier, France
| | - Roland Kölliker
- Molecular Plant Breeding, Institute of Agricultural Sciences, ETH Zürich, Zurich, Switzerland
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27
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Haq F, Xu X, Ma W, Shah SMA, Liu L, Zhu B, Zou L, Chen G. A Xanthomonas transcription activator-like effector is trapped in nonhost plants for immunity. PLANT COMMUNICATIONS 2022; 3:100249. [PMID: 35059629 PMCID: PMC8760140 DOI: 10.1016/j.xplc.2021.100249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 08/29/2021] [Accepted: 10/13/2021] [Indexed: 05/10/2023]
Abstract
Xanthomonas oryzae pv. oryzae (Xoo), the causal agent of bacterial leaf blight in rice, delivers transcription activator-like effector (TALE) proteins into host cells to activate susceptibility or resistance (R) genes that promote disease or immunity, respectively. Nonhost plants serve as potential reservoirs of R genes; consequently, nonhost R genes may trap TALEs to trigger an immune response. In this study, we screened 17 Xoo TALEs for their ability to induce a hypersensitive response (HR) in the nonhost plant Nicotiana benthamiana (Nb); only AvrXa10 elicited an HR when transiently expressed in Nb. The HR generated by AvrXa10 required both the central repeat region and the activation domain, suggesting a specific interaction between AvrXa10 and a potential R-like gene in nonhost plants. Evans blue staining and ion leakage measurements confirmed that the AvrXa10-triggered HR was a form of cell death, and the transient expression of AvrXa10 in Nb induced immune responses. Genes targeted by AvrXa10 in the Nb genome were identified by transcriptome profiling and prediction of effector binding sites. Using several approaches (in vivo reporter assays, electrophoretic mobility-shift assays, targeted designer TALEs, and on-spot gene silencing), we confirmed that AvrXa10 targets NbZnFP1, a C2H2-type zinc finger protein that resides in the nucleus. Functional analysis indicated that overexpression of NbZnFP1 and its rice orthologs triggered cell death in rice protoplasts. An NbZnFP1 ortholog was also identified in tomato and was specifically activated by AvrXa10. These results demonstrate that NbZnFP1 is a nonhost R gene that traps AvrXa10 to promote plant immunity in Nb.
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Affiliation(s)
- Fazal Haq
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
- Key Laboratory of Urban Agriculture of the Ministry of Agriculture, Shanghai, 200240, China
| | - Xiameng Xu
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
- Key Laboratory of Urban Agriculture of the Ministry of Agriculture, Shanghai, 200240, China
| | - Wenxiu Ma
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
- Key Laboratory of Urban Agriculture of the Ministry of Agriculture, Shanghai, 200240, China
| | - Syed Mashab Ali Shah
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
- Key Laboratory of Urban Agriculture of the Ministry of Agriculture, Shanghai, 200240, China
| | - Linlin Liu
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
- Key Laboratory of Urban Agriculture of the Ministry of Agriculture, Shanghai, 200240, China
| | - Bo Zhu
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - Lifang Zou
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
- Key Laboratory of Urban Agriculture of the Ministry of Agriculture, Shanghai, 200240, China
| | - Gongyou Chen
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
- Key Laboratory of Urban Agriculture of the Ministry of Agriculture, Shanghai, 200240, China
- Corresponding author
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28
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Koseoglou E, van der Wolf JM, Visser RGF, Bai Y. Susceptibility reversed: modified plant susceptibility genes for resistance to bacteria. TRENDS IN PLANT SCIENCE 2022; 27:69-79. [PMID: 34400073 DOI: 10.1016/j.tplants.2021.07.018] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 07/20/2021] [Accepted: 07/24/2021] [Indexed: 05/26/2023]
Abstract
Plants have evolved complex defence mechanisms to avoid invasion of potential pathogens. Despite this, adapted pathogens deploy effector proteins to manipulate host susceptibility (S) genes, rendering plant defences ineffective. The identification and mutation of plant S genes exploited by bacterial pathogens are important for the generation of crops with durable and broad-spectrum resistance. Application of mutant S genes in the breeding of resistant crops is limited because of potential pleiotropy. New genome editing techniques open up new possibilities for the modification of S genes. In this review, we focus on S genes manipulated by bacteria and propose ways for their identification and precise modification. Finally, we propose that genes coding for transporter proteins represent a new group of S genes.
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Affiliation(s)
- Eleni Koseoglou
- Plant Breeding, Wageningen University & Research, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands
| | - Jan M van der Wolf
- Biointeractions & Plant Health, Wageningen University & Research, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands
| | - Richard G F Visser
- Plant Breeding, Wageningen University & Research, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands
| | - Yuling Bai
- Plant Breeding, Wageningen University & Research, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands.
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29
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Research Progress of ATGs Involved in Plant Immunity and NPR1 Metabolism. Int J Mol Sci 2021; 22:ijms222212093. [PMID: 34829975 PMCID: PMC8623690 DOI: 10.3390/ijms222212093] [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: 09/26/2021] [Revised: 11/04/2021] [Accepted: 11/04/2021] [Indexed: 12/12/2022] Open
Abstract
Autophagy is an important pathway of degrading excess and abnormal proteins and organelles through their engulfment into autophagosomes that subsequently fuse with the vacuole. Autophagy-related genes (ATGs) are essential for the formation of autophagosomes. To date, about 35 ATGs have been identified in Arabidopsis, which are involved in the occurrence and regulation of autophagy. Among these, 17 proteins are related to resistance against plant pathogens. The transcription coactivator non-expressor of pathogenesis-related genes 1 (NPR1) is involved in innate immunity and acquired resistance in plants, which regulates most salicylic acid (SA)-responsive genes. This paper mainly summarizes the role of ATGs and NPR1 in plant immunity and the advancement of research on ATGs in NPR1 metabolism, providing a new idea for exploring the relationship between ATGs and NPR1.
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30
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Gorshkov V, Tsers I. Plant susceptible responses: the underestimated side of plant-pathogen interactions. Biol Rev Camb Philos Soc 2021; 97:45-66. [PMID: 34435443 PMCID: PMC9291929 DOI: 10.1111/brv.12789] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 08/12/2021] [Accepted: 08/13/2021] [Indexed: 12/18/2022]
Abstract
Plant susceptibility to pathogens is usually considered from the perspective of the loss of resistance. However, susceptibility cannot be equated with plant passivity since active host cooperation may be required for the pathogen to propagate and cause disease. This cooperation consists of the induction of reactions called susceptible responses that transform a plant from an autonomous biological unit into a component of a pathosystem. Induced susceptibility is scarcely discussed in the literature (at least compared to induced resistance) although this phenomenon has a fundamental impact on plant-pathogen interactions and disease progression. This review aims to summarize current knowledge on plant susceptible responses and their regulation. We highlight two main categories of susceptible responses according to their consequences and indicate the relevance of susceptible response-related studies to agricultural practice. We hope that this review will generate interest in this underestimated aspect of plant-pathogen interactions.
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Affiliation(s)
- Vladimir Gorshkov
- Kazan Institute of Biochemistry and Biophysics, Federal Research Center Kazan Scientific Center of Russian Academy of Sciences, Kazan, 420111, Russia.,Laboratory of Plant Infectious Diseases, Federal Research Center Kazan Scientific Center of Russian Academy of Sciences, Kazan, 420111, Russia
| | - Ivan Tsers
- Laboratory of Plant Infectious Diseases, Federal Research Center Kazan Scientific Center of Russian Academy of Sciences, Kazan, 420111, Russia
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31
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Kachroo P, Burch-Smith TM, Grant M. An Emerging Role for Chloroplasts in Disease and Defense. ANNUAL REVIEW OF PHYTOPATHOLOGY 2021; 59:423-445. [PMID: 34432508 DOI: 10.1146/annurev-phyto-020620-115813] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Chloroplasts are key players in plant immune signaling, contributing to not only de novo synthesis of defensive phytohormones but also the generation of reactive oxygen and nitrogen species following activation of pattern recognition receptors or resistance (R) proteins. The local hypersensitive response (HR) elicited by R proteins is underpinned by chloroplast-generated reactive oxygen species. HR-induced lipid peroxidation generates important chloroplast-derived signaling lipids essential to the establishment of systemic immunity. As a consequence of this pivotal role in immunity, pathogens deploy effector complements that directly or indirectly target chloroplasts to attenuate chloroplast immunity (CI). Our review summarizes the current knowledge of CI signaling and highlights common pathogen chloroplast targets and virulence strategies. We address emerging insights into chloroplast retrograde signaling in immune responses and gaps in our knowledge, including the importance of understanding chloroplast heterogeneity and chloroplast involvement in intraorganellular interactions in host immunity.
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Affiliation(s)
- Pradeep Kachroo
- Department of Plant Pathology, University of Kentucky, Lexington, Kentucky 40546, USA
| | - Tessa M Burch-Smith
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Murray Grant
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK;
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32
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Garcia-Ruiz H, Szurek B, Van den Ackerveken G. Stop helping pathogens: engineering plant susceptibility genes for durable resistance. Curr Opin Biotechnol 2021; 70:187-195. [PMID: 34153774 PMCID: PMC8878094 DOI: 10.1016/j.copbio.2021.05.005] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 05/21/2021] [Accepted: 05/23/2021] [Indexed: 11/30/2022]
Abstract
Alternatives to protect crops against diseases are desperately needed to secure world food production and make agriculture more sustainable. Genetic resistance to pathogens utilized so far is mostly based on single dominant resistance genes that mediate specific recognition of invaders and that is often rapidly broken by pathogen variants. Perturbation of plant susceptibility (S) genes offers an alternative providing plants with recessive resistance that is proposed to be more durable. S genes enable the establishment of plant disease, and their inactivation provides opportunities for resistance breeding of crops. However, loss of S gene function can have pleiotropic effects. Developments in genome editing technology promise to provide powerful methods to precisely interfere with crop S gene functions and reduce tradeoffs.
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Affiliation(s)
- Hernan Garcia-Ruiz
- Department of Plant Pathology, Nebraska Center for Virology, University of Nebraska-Lincoln, Lincoln, NE 68503, USA
| | - Boris Szurek
- PHIM Plant Health Institute, Univ Montpellier, IRD, CIRAD, INRAE, Institut Agro, Montpellier, France
| | - Guido Van den Ackerveken
- Plant-Microbe Interactions, Department of Biology, Utrecht University, Padualaan 8, 3584 CH Utrecht, Netherlands.
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Tambong JT, Xu R, Gerdis S, Daniels GC, Chabot D, Hubbard K, Harding MW. Molecular Analysis of Bacterial Isolates From Necrotic Wheat Leaf Lesions Caused by Xanthomonas translucens, and Description of Three Putative Novel Species, Sphingomonas albertensis sp. nov., Pseudomonas triticumensis sp. nov. and Pseudomonas foliumensis sp. nov. Front Microbiol 2021; 12:666689. [PMID: 34093484 PMCID: PMC8170138 DOI: 10.3389/fmicb.2021.666689] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 03/22/2021] [Indexed: 11/13/2022] Open
Abstract
Xanthomonas translucens is the etiological agent of the wheat bacterial leaf streak (BLS) disease. The isolation of this pathogen is usually based on the Wilbrink's-boric acid-cephalexin semi-selective medium which eliminates 90% of other bacteria, some of which might be novel species. In our study, a general purpose nutrient agar was used to isolate 49 bacterial strains including X. translucens from necrotic wheat leaf tissues. Maximum likelihood cluster analysis of 16S rRNA sequences grouped the strains into 10 distinct genera. Pseudomonas (32.7%) and Pantoea (28.6%) were the dominant genera while Xanthomonas, Clavibacter and Curtobacterium had 8.2%, each. Erwinia and Sphingomonas had two strains, each. BLAST and phylogenetic analyses of multilocus sequence analysis (MLSA) of specific housekeeping genes taxonomically assigned all the strains to validly described bacterial species, except three strains (10L4B, 12L4D and 32L3A) of Pseudomonas and two (23L3C and 15L3B) of Sphingomonas. Strains 10L4B and12L4D had Pseudomonas caspiana as their closest known type strain while strain 32L3A was closest to Pseudomonas asturiensis. Sphingomonas sp. strains 23L3C and 15L3B were closest to S. faeni based on MLSA analysis. Our data on MLSA, whole genome-based cluster analysis, DNA-DNA hybridization and average nucleotide identity, matrix-assisted laser desorption/ionization-time-of-flight, chemotaxonomy and phenotype affirmed that these 5 strains constitute three novel lineages and are taxonomically described in this study. We propose the names, Sphingomonas albertensis sp. nov. (type strain 23L3CT = DOAB 1063T = CECT 30248T = LMG 32139T), Pseudomonas triticumensis sp. nov. (type strain 32L3AT = DOAB 1067T = CECT 30249T = LMG 32140T) and Pseudomonas foliumensis sp. nov. (type strain 10L4BT = DOAB 1069T = CECT 30250T = LMG 32142T). Comparative genomics of these novel species, relative to their closest type strains, revealed unique repertoires of core secretion systems and secondary metabolites/antibiotics. Also, the detection of CRISPR-Cas systems in the genomes of these novel species suggests an acquired mechanism for resistance against foreign mobile genetic elements. The results presented here revealed a cohabitation, within the BLS lesions, of diverse bacterial species, including novel lineages.
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Affiliation(s)
- James T Tambong
- Ottawa Research and Development Centre, Agriculture and Agri-Food Canada, Ottawa, ON, Canada
| | - Renlin Xu
- Ottawa Research and Development Centre, Agriculture and Agri-Food Canada, Ottawa, ON, Canada
| | - Suzanne Gerdis
- Ottawa Research and Development Centre, Agriculture and Agri-Food Canada, Ottawa, ON, Canada
| | - Greg C Daniels
- Crop Diversification Centre South, Alberta Agriculture and Forestry, Brooks, AB, Canada
| | - Denise Chabot
- Ottawa Research and Development Centre, Agriculture and Agri-Food Canada, Ottawa, ON, Canada
| | - Keith Hubbard
- Ottawa Research and Development Centre, Agriculture and Agri-Food Canada, Ottawa, ON, Canada
| | - Michael W Harding
- Crop Diversification Centre South, Alberta Agriculture and Forestry, Brooks, AB, Canada
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Shah SMA, Khojasteh M, Wang Q, Taghavi SM, Xu Z, Khodaygan P, Zou L, Mohammadikhah S, Chen G, Osdaghi E. Genomics-Enabled Novel Insight Into the Pathovar-Specific Population Structure of the Bacterial Leaf Streak Pathogen Xanthomonas translucens in Small Grain Cereals. Front Microbiol 2021; 12:674952. [PMID: 34122388 PMCID: PMC8195340 DOI: 10.3389/fmicb.2021.674952] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 04/27/2021] [Indexed: 11/30/2022] Open
Abstract
The Gram-negative bacterium Xanthomonas translucens infects a wide range of gramineous plants with a notable impact on small grain cereals. However, genomics-informed intra-species population structure and virulence repertories of the pathogen have rarely been investigated. In this study, the complete genome sequences of seven X. translucens strains representing an entire set of genetic diversity of two pathovars X. translucens pv. undulosa and X. translucens pv. translucens is provided and compared with those of seven publicly available complete genomes of the pathogen. Organization of the 25 type III secretion system genes in all the 14 X. translucens strains was exactly the same, while TAL effector genes localized singly or in clusters across four loci in X. translucens pv. translucens and five to six loci in X. translucens pv. undulosa. Beside two previously unreported endogenous plasmids in X. translucens pv. undulosa, and variations in repeat variable diresidue (RVD) of the 14 strains, tal1a of X. translucens pv. translucens strain XtKm8 encode the new RVDs HE and YI which have not previously been reported in xanthomonads. Further, a number of truncated tal genes were predicted among the 14 genomes lacking conserved BamHI site at N-terminus and SphI site at C-terminus. Our data have doubled the number of complete genomes of X. translucens clarifying the population structure and genomics of the pathogen to pave the way in the small grain cereals industry for disease resistance breeding in the 21st century's agriculture.
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Affiliation(s)
- Syed Mashab Ali Shah
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - Moein Khojasteh
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
- Department of Plant Protection, School of Agriculture, Shiraz University, Shiraz, Iran
- Department of Plant Protection, University of Tehran, Karaj, Iran
| | - Qi Wang
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - S. Mohsen Taghavi
- Department of Plant Protection, School of Agriculture, Shiraz University, Shiraz, Iran
| | - Zhengyin Xu
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - Pejman Khodaygan
- Department of Plant Protection, Faculty of Agriculture, Vali-e-Asr University of Rafsanjan, Rafsanjan, Iran
| | - Lifang Zou
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - Sedighe Mohammadikhah
- Department of Plant Protection, Faculty of Agriculture, Vali-e-Asr University of Rafsanjan, Rafsanjan, Iran
| | - Gongyou Chen
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - Ebrahim Osdaghi
- Department of Plant Protection, University of Tehran, Karaj, Iran
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Schreiber KJ, Chau-Ly IJ, Lewis JD. What the Wild Things Do: Mechanisms of Plant Host Manipulation by Bacterial Type III-Secreted Effector Proteins. Microorganisms 2021; 9:1029. [PMID: 34064647 PMCID: PMC8150971 DOI: 10.3390/microorganisms9051029] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 05/03/2021] [Accepted: 05/04/2021] [Indexed: 01/05/2023] Open
Abstract
Phytopathogenic bacteria possess an arsenal of effector proteins that enable them to subvert host recognition and manipulate the host to promote pathogen fitness. The type III secretion system (T3SS) delivers type III-secreted effector proteins (T3SEs) from bacterial pathogens such as Pseudomonas syringae, Ralstonia solanacearum, and various Xanthomonas species. These T3SEs interact with and modify a range of intracellular host targets to alter their activity and thereby attenuate host immune signaling. Pathogens have evolved T3SEs with diverse biochemical activities, which can be difficult to predict in the absence of structural data. Interestingly, several T3SEs are activated following injection into the host cell. Here, we review T3SEs with documented enzymatic activities, as well as T3SEs that facilitate virulence-promoting processes either indirectly or through non-enzymatic mechanisms. We discuss the mechanisms by which T3SEs are activated in the cell, as well as how T3SEs modify host targets to promote virulence or trigger immunity. These mechanisms may suggest common enzymatic activities and convergent targets that could be manipulated to protect crop plants from infection.
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Affiliation(s)
- Karl J. Schreiber
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94710, USA; (K.J.S.); (I.J.C.-L.)
| | - Ilea J. Chau-Ly
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94710, USA; (K.J.S.); (I.J.C.-L.)
| | - Jennifer D. Lewis
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94710, USA; (K.J.S.); (I.J.C.-L.)
- Plant Gene Expression Center, United States Department of Agriculture, University of California, Berkeley, CA 94710, USA
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Zlobin N, Lebedeva M, Monakhova Y, Ustinova V, Taranov V. An ERF121 transcription factor from Brassica oleracea is a target for the conserved TAL-effectors from different Xanthomonas campestris pv. campestris strains. MOLECULAR PLANT PATHOLOGY 2021; 22:618-624. [PMID: 33650275 PMCID: PMC8035633 DOI: 10.1111/mpp.13048] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 01/19/2021] [Accepted: 02/04/2021] [Indexed: 05/19/2023]
Abstract
Transcription activator-like effectors (TALEs), which induce the expression of specific plant genes to promote infection, are the main pathogenic determinants of various Xanthomonas bacteria. However, investigation of TALEs from Xanthomonas campestris pv. campestris, which causes black rot disease of crucifers, received little attention. In this study, we used PCR-based amplification followed by SMRT amplicon sequencing to identify TALE genes in several X. campestris pv. campestris strains. Computational prediction in conjunction with quantitative reverse transcription PCR analysis was used to find their targets in the Brassica oleracea genome. Transcription factor ERF121, from the AP2/ERF family, was identified as target gene for the conserved TALEs from multiple X. campestris pv. campestris strains. Several members of this family from diverse plants were previously identified as targets of TALEs from different Xanthomonas species. We propose that TALE-dependent activation of AP2/ERF transcription factors promotes susceptibility to Xanthomonas through the misregulation of plant defence pathways.
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Affiliation(s)
- Nikolay Zlobin
- Laboratory of Plant Stress ToleranceAll‐Russia Research Institute of Agricultural BiotechnologyMoscowRussia
| | - Marina Lebedeva
- Laboratory of Plant Stress ToleranceAll‐Russia Research Institute of Agricultural BiotechnologyMoscowRussia
| | - Yuliya Monakhova
- Laboratory of Synthesis and Analysis of Bioorganic CompoundsAll‐Russia Research Institute of Agricultural BiotechnologyMoscowRussia
| | - Vera Ustinova
- Pushchino Scientific Center for Biological Research of the Russian Academy of SciencesG.K. Skryabin Institute of Biochemistry and Physiology of Microorganisms of the Russian Academy of SciencesPushchinoRussia
- Syntol LLCMoscowRussia
| | - Vasiliy Taranov
- Laboratory of Plant Stress ToleranceAll‐Russia Research Institute of Agricultural BiotechnologyMoscowRussia
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Littlejohn GR, Breen S, Smirnoff N, Grant M. Chloroplast immunity illuminated. THE NEW PHYTOLOGIST 2021; 229:3088-3107. [PMID: 33206379 DOI: 10.1111/nph.17076] [Citation(s) in RCA: 57] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 09/12/2020] [Indexed: 05/04/2023]
Abstract
The chloroplast has recently emerged as pivotal to co-ordinating plant defence responses and as a target of plant pathogens. Beyond its central position in oxygenic photosynthesis and primary metabolism - key targets in the complex virulence strategies of diverse pathogens - the chloroplast integrates, decodes and responds to environmental signals. The capacity of chloroplasts to synthesize phytohormones and a diverse range of secondary metabolites, combined with retrograde and reactive oxygen signalling, provides exquisite flexibility to both perceive and respond to biotic stresses. These processes also represent a plethora of opportunities for pathogens to evolve strategies to directly or indirectly target 'chloroplast immunity'. This review covers the contribution of the chloroplast to pathogen associated molecular pattern and effector triggered immunity as well as systemic acquired immunity. We address phytohormone modulation of immunity and surmise how chloroplast-derived reactive oxygen species underpin chloroplast immunity through indirect evidence inferred from genetic modification of core chloroplast components and direct pathogen targeting of the chloroplast. We assess the impact of transcriptional reprogramming of nuclear-encoded chloroplast genes during disease and defence and look at future research challenges.
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Affiliation(s)
- George R Littlejohn
- School of Biological and Marine Sciences, University of Plymouth, Plymouth, PL4 8AA, UK
| | - Susan Breen
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK
| | - Nicholas Smirnoff
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4QD, UK
| | - Murray Grant
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK
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TAL Effector Repertoires of Strains of Xanthomonas phaseoli pv. manihotis in Commercial Cassava Crops Reveal High Diversity at the Country Scale. Microorganisms 2021; 9:microorganisms9020315. [PMID: 33557009 PMCID: PMC7913752 DOI: 10.3390/microorganisms9020315] [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: 11/15/2020] [Revised: 12/17/2020] [Accepted: 12/24/2020] [Indexed: 12/13/2022] Open
Abstract
Transcription activator-like effectors (TALEs) play a significant role for pathogenesis in several xanthomonad pathosystems. Xanthomonas phaseoli pv. manihotis (Xpm), the causal agent of Cassava Bacterial Blight (CBB), uses TALEs to manipulate host metabolism. Information about Xpm TALEs and their target genes in cassava is scarce, but has been growing in the last few years. We aimed to characterize the TALE diversity in Colombian strains of Xpm and to screen for TALE-targeted gene candidates. We selected eighteen Xpm strains based on neutral genetic diversity at a country scale to depict the TALE diversity among isolates from cassava productive regions. RFLP analysis showed that Xpm strains carry TALomes with a bimodal size distribution, and affinity-based clustering of the sequenced TALEs condensed this variability mainly into five clusters. We report on the identification of 13 novel variants of TALEs in Xpm, as well as a functional variant with 22 repeats that activates the susceptibility gene MeSWEET10a, a previously reported target of TAL20Xam668. Transcriptomics and EBE prediction analyses resulted in the selection of several TALE-targeted candidate genes and two potential cases of functional convergence. This study provides new bases for assessing novel potential TALE targets in the Xpm–cassava interaction, which could be important factors that define the fate of the infection.
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Teper D, Wang N. Consequences of adaptation of TAL effectors on host susceptibility to Xanthomonas. PLoS Genet 2021; 17:e1009310. [PMID: 33465093 PMCID: PMC7845958 DOI: 10.1371/journal.pgen.1009310] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 01/29/2021] [Accepted: 12/11/2020] [Indexed: 12/03/2022] Open
Abstract
Transcription activator-like effectors (TALEs) are virulence factors of Xanthomonas that induce the expression of host susceptibility (S) genes by specifically binding to effector binding elements (EBEs) in their promoter regions. The DNA binding specificity of TALEs is dictated by their tandem repeat regions, which are highly variable between different TALEs. Mutation of the EBEs of S genes is being utilized as a key strategy to generate resistant crops against TALE-dependent pathogens. However, TALE adaptations through rearrangement of their repeat regions is a potential obstacle for successful implementation of this strategy. We investigated the consequences of TALE adaptations in the citrus pathogen Xanthomonas citri subsp. citri (Xcc), in which PthA4 is the TALE required for pathogenicity, whereas CsLOB1 is the corresponding susceptibility gene, on host resistance. Seven TALEs, containing two-to-nine mismatching-repeats to the EBEPthA4 that were unable to induce CsLOB1 expression, were introduced into Xcc pthA4:Tn5 and adaptation was simulated by repeated inoculations into and isolations from sweet orange for a duration of 30 cycles. While initially all strains failed to promote disease, symptoms started to appear between 9–28 passages in four TALEs, which originally harbored two-to-five mismatches. Sequence analysis of adapted TALEs identified deletions and mutations within the TALE repeat regions which enhanced putative affinity to the CsLOB1 promoter. Sequence analyses suggest that TALEs adaptations result from recombinations between repeats of the TALEs. Reintroduction of these adapted TALEs into Xcc pthA4:Tn5 restored the ability to induce the expression of CsLOB1, promote disease symptoms and colonize host plants. TALEs harboring seven-to-nine mismatches were unable to adapt to overcome the incompatible interaction. Our study experimentally documented TALE adaptations to incompatible EBE and provided strategic guidance for generation of disease resistant crops against TALE-dependent pathogens. Mutation of the EBEs of susceptibility (S) genes via genome editing and utilization of naturally occurring EBE variants have been used to generate disease resistant plants. However, TALE adaptations may lead to resistance loss, limiting the long-term efficacy of the strategy. We utilized an experimental evolution approach to test TALEs adaptations in the Xanthomonas citri-citrus pathosystem using designer TALEs that cannot recognize the EBE of host targets. We identified adaptive TALE mutations and deletions that occurred during less than 30 cycles of repeated infections, which reconstituted the virulence on the host. Adaptive variants originated from TALEs that harbored a small number of mismatches (≤5) to the EBE, whereas designer TALEs that harbored larger number of mismatches (≥7) to the EBE failed to adapt in the duration of this study. Our study experimentally demonstrates adaptive rearrangements of TALEs during host adaptation and suggests that the potential durability in the resistance of modified crops should be a significant factor to be considered prior to their introduction into the field.
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Affiliation(s)
- Doron Teper
- 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
| | - 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
- * E-mail:
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40
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Secrete or perish: The role of secretion systems in Xanthomonas biology. Comput Struct Biotechnol J 2020; 19:279-302. [PMID: 33425257 PMCID: PMC7777525 DOI: 10.1016/j.csbj.2020.12.020] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 12/13/2020] [Accepted: 12/13/2020] [Indexed: 12/22/2022] Open
Abstract
Bacteria of the Xanthomonas genus are mainly phytopathogens of a large variety of crops of economic importance worldwide. Xanthomonas spp. rely on an arsenal of protein effectors, toxins and adhesins to adapt to the environment, compete with other microorganisms and colonize plant hosts, often causing disease. These protein effectors are mainly delivered to their targets by the action of bacterial secretion systems, dedicated multiprotein complexes that translocate proteins to the extracellular environment or directly into eukaryotic and prokaryotic cells. Type I to type VI secretion systems have been identified in Xanthomonas genomes. Recent studies have unravelled the diverse roles played by the distinct types of secretion systems in adaptation and virulence in xanthomonads, unveiling new aspects of their biology. In addition, genome sequence information from a wide range of Xanthomonas species and pathovars have become available recently, uncovering a heterogeneous distribution of the distinct families of secretion systems within the genus. In this review, we describe the architecture and mode of action of bacterial type I to type VI secretion systems and the distribution and functions associated with these important nanoweapons within the Xanthomonas genus.
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García-Andrade J, González B, Gonzalez-Guzman M, Rodriguez PL, Vera P. The Role of ABA in Plant Immunity is Mediated through the PYR1 Receptor. Int J Mol Sci 2020; 21:ijms21165852. [PMID: 32824010 PMCID: PMC7461614 DOI: 10.3390/ijms21165852] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 08/07/2020] [Accepted: 08/09/2020] [Indexed: 01/13/2023] Open
Abstract
ABA is involved in plant responses to a broad range of pathogens and exhibits complex antagonistic and synergistic relationships with salicylic acid (SA) and ethylene (ET) signaling pathways, respectively. However, the specific receptor of ABA that triggers the positive and negative responses of ABA during immune responses remains unknown. Through a reverse genetic analysis, we identified that PYR1, a member of the family of PYR/PYL/RCAR ABA receptors, is transcriptionally upregulated and specifically perceives ABA during biotic stress, initiating downstream signaling mediated by ABA-activated SnRK2 protein kinases. This exerts a damping effect on SA-mediated signaling, required for resistance to biotrophic pathogens, and simultaneously a positive control over the resistance to necrotrophic pathogens controlled by ET. We demonstrated that PYR1-mediated signaling exerted control on a priori established hormonal cross-talk between SA and ET, thereby redirecting defense outputs. Defects in ABA/PYR1 signaling activated SA biosynthesis and sensitized plants for immune priming by poising SA-responsive genes for enhanced expression. As a trade-off effect, pyr1-mediated activation of the SA pathway blunted ET perception, which is pivotal for the activation of resistance towards fungal necrotrophs. The specific perception of ABA by PYR1 represented a regulatory node, modulating different outcomes in disease resistance.
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Affiliation(s)
| | | | | | | | - Pablo Vera
- Correspondence: ; Tel.: +34-963877884; Fax: +34-963877859
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Cohen SP, Leach JE. High temperature-induced plant disease susceptibility: more than the sum of its parts. CURRENT OPINION IN PLANT BIOLOGY 2020; 56:235-241. [PMID: 32321671 DOI: 10.1016/j.pbi.2020.02.008] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 02/25/2020] [Accepted: 02/28/2020] [Indexed: 05/20/2023]
Abstract
Higher temperatures associated with climate change often increase the severity of plant diseases. An understanding of how plants respond to pathogens during high temperature stress is required for crop improvement, but the molecular mechanisms underlying this response are largely unknown. Mechanistic research has primarily focused on plant responses during either single stresses or heat-induced loss of single gene resistance. Transcriptome analyses of plant responses to a single stress compared to combined-stresses reveal significant differences showing that single-stress response studies are inadequate for determining the mechanisms of high temperature-induced disease susceptibility. To combat plant disease in light of climate change, future research will require comprehensive study designs and analyses.
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Affiliation(s)
- Stephen P Cohen
- Department of Agricultural Biology, Colorado State University, Fort Collins, CO, 80523-1177, United States; Department of Plant Pathology, The Ohio State University, Columbus, OH, 43210, United States
| | - Jan E Leach
- Department of Agricultural Biology, Colorado State University, Fort Collins, CO, 80523-1177, United States.
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Xue J, Lu Z, Liu W, Wang S, Lu D, Wang X, He X. The genetic arms race between plant and Xanthomonas: lessons learned from TALE biology. SCIENCE CHINA-LIFE SCIENCES 2020; 64:51-65. [PMID: 32661897 DOI: 10.1007/s11427-020-1699-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 03/29/2020] [Indexed: 10/23/2022]
Abstract
The pathogenic bacterial genus Xanthomonas infects a wide variety of host plants and causes devastating diseases in many crops. Transcription activator-like effectors (TALEs) are important virulence factors secreted by Xanthomonas with the ability to directly bind to the promoters of target genes in plant hosts and activate their expression, which often facilitates the proliferation of pathogens. Understanding how plants cope with TALEs will provide mechanistic insights into crop breeding for Xanthomonas defense. Over the past 30 years, numerous studies have revealed the modes of action of TALEs in plant cells and plant defense strategies to overcome TALE attack. Based on these findings, new technologies were adopted for disease management to optimize crop production. In this article, we will review the most recent advances in the evolutionary arms race between plant resistance and TALEs from Xanthomonas, with a specific focus on TALE applications in the development of novel breeding strategies for durable and broad-spectrum resistance.
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Affiliation(s)
- Jiao Xue
- Rice Research Institute, Guangdong Academy of Agricultural Sciences, Guangdong Provincial Key Laboratory of New Technology in Rice Breeding, Guangzhou, 510640, China
| | - Zhanhua Lu
- Rice Research Institute, Guangdong Academy of Agricultural Sciences, Guangdong Provincial Key Laboratory of New Technology in Rice Breeding, Guangzhou, 510640, China
| | - Wei Liu
- Rice Research Institute, Guangdong Academy of Agricultural Sciences, Guangdong Provincial Key Laboratory of New Technology in Rice Breeding, Guangzhou, 510640, China
| | - Shiguang Wang
- Rice Research Institute, Guangdong Academy of Agricultural Sciences, Guangdong Provincial Key Laboratory of New Technology in Rice Breeding, Guangzhou, 510640, China
| | - Dongbai Lu
- Rice Research Institute, Guangdong Academy of Agricultural Sciences, Guangdong Provincial Key Laboratory of New Technology in Rice Breeding, Guangzhou, 510640, China
| | - Xiaofei Wang
- Rice Research Institute, Guangdong Academy of Agricultural Sciences, Guangdong Provincial Key Laboratory of New Technology in Rice Breeding, Guangzhou, 510640, China
| | - Xiuying He
- Rice Research Institute, Guangdong Academy of Agricultural Sciences, Guangdong Provincial Key Laboratory of New Technology in Rice Breeding, Guangzhou, 510640, China.
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Timilsina S, Potnis N, Newberry EA, Liyanapathiranage P, Iruegas-Bocardo F, White FF, Goss EM, Jones JB. Xanthomonas diversity, virulence and plant-pathogen interactions. Nat Rev Microbiol 2020; 18:415-427. [PMID: 32346148 DOI: 10.1038/s41579-020-0361-8] [Citation(s) in RCA: 132] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/19/2020] [Indexed: 12/19/2022]
Abstract
Xanthomonas spp. encompass a wide range of plant pathogens that use numerous virulence factors for pathogenicity and fitness in plant hosts. In this Review, we examine recent insights into host-pathogen co-evolution, diversity in Xanthomonas populations and host specificity of Xanthomonas spp. that have substantially improved our fundamental understanding of pathogen biology. We emphasize the virulence factors in xanthomonads, such as type III secreted effectors including transcription activator-like effectors, type II secretion systems, diversity resulting in host specificity, evolution of emerging strains, activation of susceptibility genes and strategies of host evasion. We summarize the genomic diversity in several Xanthomonas spp. and implications for disease outbreaks, management strategies and breeding for disease resistance.
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Affiliation(s)
- Sujan Timilsina
- Plant Pathology Department, University of Florida, Gainesville, FL, USA
| | - Neha Potnis
- Entomology and Plant Pathology, Auburn University, Auburn, AL, USA
| | - Eric A Newberry
- Entomology and Plant Pathology, Auburn University, Auburn, AL, USA
| | | | | | - Frank F White
- Plant Pathology Department, University of Florida, Gainesville, FL, USA
| | - Erica M Goss
- Plant Pathology Department, University of Florida, Gainesville, FL, USA. .,Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA.
| | - Jeffrey B Jones
- Plant Pathology Department, University of Florida, Gainesville, FL, USA.
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Haq F, Xie S, Huang K, Shah SMA, Ma W, Cai L, Xu X, Xu Z, Wang S, Zou L, Zhu B, Chen G. Identification of a virulence tal gene in the cotton pathogen, Xanthomonas citri pv. malvacearum strain Xss-V 2-18. BMC Microbiol 2020; 20:91. [PMID: 32293266 PMCID: PMC7160923 DOI: 10.1186/s12866-020-01783-x] [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: 12/24/2019] [Accepted: 04/05/2020] [Indexed: 01/22/2023] Open
Abstract
Background Bacterial blight of cotton (BBC), which is caused by the bacterium Xanthomonas citri pv. malvacearum (Xcm), is a destructive disease in cotton. Transcription activator-like effectors (TALEs), encoded by tal-genes, play critical roles in the pathogenesis of xanthomonads. Characterized strains of cotton pathogenic Xcm harbor 8–12 different tal genes and only one of them is functionally decoded. Further identification of novel tal genes in Xcm strains with virulence contributions are prerequisite to decipher the Xcm-cotton interactions. Results In this study, we identified six tal genes in Xss-V2–18, a highly-virulent strain of Xcm from China, and assessed their role in BBC. RFLP-based Southern hybridization assays indicated that Xss-V2–18 harbors the six tal genes on a plasmid. The plasmid-encoded tal genes were isolated by cloning BamHI fragments and screening clones by colony hybridization. The tal genes were sequenced by inserting a Tn5 transposon in the DNA encoding the central repeat region (CRR) of each tal gene. Xcm TALome evolutionary relationship based on TALEs CRR revealed relatedness of Xss-V2–18 to MSCT1 and MS14003 from the United States. However, Tal2 of Xss-V2–18 differs at two repeat variable diresidues (RVDs) from Tal6 and Tal26 in MSCT1 and MS14003, respectively, inferred functional dissimilarity. The suicide vector pKMS1 was then used to construct tal deletion mutants in Xcm Xss-V2–18. The mutants were evaluated for pathogenicity in cotton based on symptomology and growth in planta. Four mutants showed attenuated virulence and all contained mutations in tal2. One tal2 mutant designated M2 was further investigated in complementation assays. When tal2 was introduced into Xcm M2 and expressed in trans, the mutant was complemented for both symptoms and growth in planta, thus indicating that tal2 functions as a virulence factor in Xcm Xss-V2–18. Conclusions Overall, the results demonstrated that Tal2 is a major pathogenicity factor in Xcm strain Xss-V2–18 that contributes significantly in BBC. This study provides a foundation for future efforts aimed at identifying susceptibility genes in cotton that are targeted by Tal2.
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Affiliation(s)
- Fazal Haq
- School of Agriculture and Biology, Shanghai Jiao Tong University/Key Laboratory of Urban Agriculture by the Ministry of Agriculture, Shanghai, 200240, China.,State Key laboratory of Microbial Metabolism, School of life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Shiwang Xie
- School of Agriculture and Biology, Shanghai Jiao Tong University/Key Laboratory of Urban Agriculture by the Ministry of Agriculture, Shanghai, 200240, China
| | - Kunxuan Huang
- School of Agriculture and Biology, Shanghai Jiao Tong University/Key Laboratory of Urban Agriculture by the Ministry of Agriculture, Shanghai, 200240, China.,State Key laboratory of Microbial Metabolism, School of life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Syed Mashab Ali Shah
- School of Agriculture and Biology, Shanghai Jiao Tong University/Key Laboratory of Urban Agriculture by the Ministry of Agriculture, Shanghai, 200240, China.,State Key laboratory of Microbial Metabolism, School of life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Wenxiu Ma
- School of Agriculture and Biology, Shanghai Jiao Tong University/Key Laboratory of Urban Agriculture by the Ministry of Agriculture, Shanghai, 200240, China.,State Key laboratory of Microbial Metabolism, School of life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Lulu Cai
- School of Agriculture and Biology, Shanghai Jiao Tong University/Key Laboratory of Urban Agriculture by the Ministry of Agriculture, Shanghai, 200240, China.,State Key laboratory of Microbial Metabolism, School of life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Xiameng Xu
- School of Agriculture and Biology, Shanghai Jiao Tong University/Key Laboratory of Urban Agriculture by the Ministry of Agriculture, Shanghai, 200240, China.,State Key laboratory of Microbial Metabolism, School of life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Zhengyin Xu
- School of Agriculture and Biology, Shanghai Jiao Tong University/Key Laboratory of Urban Agriculture by the Ministry of Agriculture, Shanghai, 200240, China.,State Key laboratory of Microbial Metabolism, School of life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Sai Wang
- School of Agriculture and Biology, Shanghai Jiao Tong University/Key Laboratory of Urban Agriculture by the Ministry of Agriculture, Shanghai, 200240, China
| | - Lifang Zou
- School of Agriculture and Biology, Shanghai Jiao Tong University/Key Laboratory of Urban Agriculture by the Ministry of Agriculture, Shanghai, 200240, China.,State Key laboratory of Microbial Metabolism, School of life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Bo Zhu
- School of Agriculture and Biology, Shanghai Jiao Tong University/Key Laboratory of Urban Agriculture by the Ministry of Agriculture, Shanghai, 200240, China
| | - Gongyou Chen
- School of Agriculture and Biology, Shanghai Jiao Tong University/Key Laboratory of Urban Agriculture by the Ministry of Agriculture, Shanghai, 200240, China. .,State Key laboratory of Microbial Metabolism, School of life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China.
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Sapkota S, Mergoum M, Liu Z. The translucens group of Xanthomonas translucens: Complicated and important pathogens causing bacterial leaf streak on cereals. MOLECULAR PLANT PATHOLOGY 2020; 21:291-302. [PMID: 31967397 PMCID: PMC7036361 DOI: 10.1111/mpp.12909] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 11/14/2019] [Accepted: 12/21/2019] [Indexed: 05/31/2023]
Abstract
UNLABELLED Xanthomonas translucens is a group of gram-negative bacteria that can cause important diseases in cereal crops and forage grasses. Different pathovars have been defined according to their host ranges, and molecular and biochemical characteristics. Pathovars have been placed into two major groups: translucens and graminis. The translucens group contains the pathovars causing bacterial leaf streak (BLS) on cereal crops such as wheat, barley, triticale, rye, and oat. In recent years, BLS has re-emerged as a major problem for many wheat- and barley-producing areas worldwide. The biology of the pathogens and the host-pathogen interactions in cereal BLS diseases were poorly understood. However, recent genome sequence data have provided an insight into the bacterial phylogeny and identification and pathogenicity/virulence. Furthermore, identification of sources of resistance to BLS and mapping of the resistance genes have been initiated. TAXONOMY Kingdom Bacteria; Phylum Proteobacteria; Class Gammaproteobacteria; Order Xanthomonadales; Family Xanthomonadaceae; Genus Xanthomonas; Species X. translucens; translucens group pathovars: undulosa, translucens, cerealis, hordei, and secalis; graminis group pathovars: arrhenatheri, graminis, poae, phlei; newly established pathovar: pistaciae. HOST RANGE X. translucens mainly infects plant species in the Poaceae with the translucens group on cereal crop species and the graminis group on forage grass species. However, some strains have been isolated from, and are able to infect, ornamental asparagus and pistachio trees. Most pathovars have a narrow host range, while a few can infect a broad range of hosts. GENOME The complete genome sequence is available for two X. translucens pv. undulosa strains and one pv. translucens strain. A draft genome sequence is also available for at least one strain from each pathovar. The X. translucens pv. undulosa strain Xt4699 was the first to have its complete genome sequenced, which consists of 4,561,137 bp with total GC content approximately at 68% and 3,528 predicted genes. VIRULENCE MECHANISMS Like most xanthomonads, X. translucens utilizes a type III secretion system (T3SS) to deliver a suite of T3SS effectors (T3Es) inside plant cells. Transcription activator-like effectors, a special group of T3Es, have been identified in most of the X. translucens genomes, some of which have been implicated in virulence. Genetic factors determining host range virulence have also been identified.
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Affiliation(s)
- Suraj Sapkota
- Institute of Plant Breeding, Genetics, and GenomicsUniversity of GeorgiaGriffin Campus, GriffinGAUSA
| | - Mohamed Mergoum
- Institute of Plant Breeding, Genetics, and GenomicsUniversity of GeorgiaGriffin Campus, GriffinGAUSA
- Department of Crop and Soil SciencesUniversity of GeorgiaGriffin Campus, GriffinGAUSA
| | - Zhaohui Liu
- Department of Plant PathologyNorth Dakota State UniversityFargoNDUSA
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