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Shantharaj D, Minsavage GV, Orbović V, Moore GA, Holmes DR, Römer P, Horvath DM, Lahaye T, Jones JB. A promoter trap in transgenic citrus mediates recognition of a broad spectrum of Xanthomonas citri pv. citri TALEs, including in planta-evolved derivatives. PLANT BIOTECHNOLOGY JOURNAL 2023; 21:2019-2032. [PMID: 37421233 PMCID: PMC10502743 DOI: 10.1111/pbi.14109] [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: 03/05/2023] [Revised: 06/09/2023] [Accepted: 06/12/2023] [Indexed: 07/10/2023]
Abstract
Citrus bacterial canker (CBC), caused by Xanthomonas citri subsp. citri (Xcc), causes dramatic losses to the citrus industry worldwide. Transcription activator-like effectors (TALEs), which bind to effector binding elements (EBEs) in host promoters and activate transcription of downstream host genes, contribute significantly to Xcc virulence. The discovery of the biochemical context for the binding of TALEs to matching EBE motifs, an interaction commonly referred to as the TALE code, enabled the in silico prediction of EBEs for each TALE protein. Using the TALE code, we engineered a synthetic resistance (R) gene, called the Xcc-TALE-trap, in which 14 tandemly arranged EBEs, each capable of autonomously recognizing a particular Xcc TALE, drive the expression of Xanthomonas avrGf2, which encodes a bacterial effector that induces plant cell death. Analysis of a corresponding transgenic Duncan grapefruit showed that transcription of the cell death-inducing executor gene, avrGf2, was strictly TALE-dependent and could be activated by several different Xcc TALE proteins. Evaluation of Xcc strains from different continents showed that the Xcc-TALE-trap mediates resistance to this global panel of Xcc isolates. We also studied in planta-evolved TALEs (eTALEs) with novel DNA-binding domains and found that these eTALEs also activate the Xcc-TALE-trap, suggesting that the Xcc-TALE-trap is likely to confer durable resistance to Xcc. Finally, we show that the Xcc-TALE-trap confers resistance not only in laboratory infection assays but also in more agriculturally relevant field studies. In conclusion, transgenic plants containing the Xcc-TALE-trap offer a promising sustainable approach to control CBC.
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Affiliation(s)
| | | | - Vladimir Orbović
- Citrus Research and Education CenterUniversity of FloridaLake AlfredFLUSA
| | - Gloria A. Moore
- Department of Horticultural SciencesUniversity of FloridaGainesvilleFLUSA
| | - Danalyn R. Holmes
- Zentrum für Molekularbiologie der Pflanzen (ZMBP)Eberhard‐Karls‐Universität TübingenTübingenGermany
| | - Patrick Römer
- Genetics, Department of BiologyLudwig‐Maximilians‐University MunichMartinsriedGermany
- Present address:
Avicare+KöthenGermany
| | | | - Thomas Lahaye
- Zentrum für Molekularbiologie der Pflanzen (ZMBP)Eberhard‐Karls‐Universität TübingenTübingenGermany
- Genetics, Department of BiologyLudwig‐Maximilians‐University MunichMartinsriedGermany
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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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Sharma A, Abrahamian P, Carvalho R, Choudhary M, Paret ML, Vallad GE, Jones JB. Future of Bacterial Disease Management in Crop Production. ANNUAL REVIEW OF PHYTOPATHOLOGY 2022; 60:259-282. [PMID: 35790244 DOI: 10.1146/annurev-phyto-021621-121806] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Bacterial diseases are a constant threat to crop production globally. Current management strategies rely on an array of tactics, including improved cultural practices; application of bactericides, plant activators, and biocontrol agents; and use of resistant varieties when available. However, effective management remains a challenge, as the longevity of deployed tactics is threatened by constantly changing bacterial populations. Increased scrutiny of the impact of pesticides on human and environmental health underscores the need for alternative solutions that are durable, sustainable, accessible to farmers, and environmentally friendly. In this review, we discuss the strengths and shortcomings of existing practices and dissect recent advances that may shape the future of bacterial disease management. We conclude that disease resistance through genome modification may be the most effective arsenal against bacterial diseases. Nonetheless, more research is necessary for developing novel bacterial disease management tactics to meet the food demand of a growing global population.
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Affiliation(s)
- Anuj Sharma
- Department of Plant Pathology, University of Florida, Gainesville, Florida, USA;
| | - Peter Abrahamian
- Department of Plant Pathology, University of Florida, Gainesville, Florida, USA;
- Gulf Coast Research and Education Center, University of Florida, Wimauma, Florida, USA
- Plant Pathogen Confirmatory Diagnostic Laboratory, USDA-APHIS, Beltsville, Maryland, USA
| | - Renato Carvalho
- Department of Plant Pathology, University of Florida, Gainesville, Florida, USA;
| | - Manoj Choudhary
- Department of Plant Pathology, University of Florida, Gainesville, Florida, USA;
| | - Mathews L Paret
- Department of Plant Pathology, University of Florida, Gainesville, Florida, USA;
- North Florida Research and Education Center, University of Florida, Quincy, Florida, USA
| | - Gary E Vallad
- Department of Plant Pathology, University of Florida, Gainesville, Florida, USA;
- Gulf Coast Research and Education Center, University of Florida, Wimauma, Florida, USA
| | - Jeffrey B Jones
- Department of Plant Pathology, University of Florida, Gainesville, Florida, USA;
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Ectopic Expression of Executor Gene Xa23 Enhances Resistance to Both Bacterial and Fungal Diseases in Rice. Int J Mol Sci 2022; 23:ijms23126545. [PMID: 35742990 PMCID: PMC9224217 DOI: 10.3390/ijms23126545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 06/01/2022] [Accepted: 06/09/2022] [Indexed: 11/17/2022] Open
Abstract
Bacterial blight (BB) and bacterial leaf streak (BLS), caused by phytopathogenic bacteria Xanthomonas oryzae pv. oryzae (Xoo) and Xanthomonas oryzae pv. oryzicola (Xoc), respectively, are the most serious bacterial diseases of rice, while blast, caused by Magnaporthe oryzae (M. oryzae), is the most devastating fungal disease in rice. Generating broad-spectrum resistance to these diseases is one of the key approaches for the sustainable production of rice. Executor (E) genes are a unique type of plant resistance (R) genes, which can specifically trap transcription activator-like effectors (TALEs) of pathogens and trigger an intense defense reaction characterized by a hypersensitive response in the host. This strong resistance is a result of programed cell death induced by the E gene expression that is only activated upon the binding of a TALE to the effector-binding element (EBE) located in the E gene promoter during the pathogen infection. Our previous studies revealed that the E gene Xa23 has the broadest and highest resistance to BB. To investigate whether the Xa23-mediated resistance is efficient against Xanthomonas oryzae pv. oryzicola (Xoc), the causal agent of BLS, we generated a new version of Xa23, designated as Xa23p1.0, to specifically trap the conserved TALEs from multiple Xoc strains. The results showed that the Xa23p1.0 confers broad resistance against both BB and BLS in rice. Moreover, our further experiment on the Xa23p1.0 transgenic plants firstly demonstrated that the E-gene-mediated defensive reaction is also effective against M. oryzae, the causal agent of the most devastating fungal disease in rice. Our current work provides a new strategy to exploit the full potential of the E-gene-mediated disease resistance in rice.
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Nowack MK, Holmes DR, Lahaye T. TALE-induced cell death executors: an origin outside immunity? TRENDS IN PLANT SCIENCE 2022; 27:536-548. [PMID: 34924289 PMCID: PMC7612725 DOI: 10.1016/j.tplants.2021.11.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 10/21/2021] [Accepted: 11/01/2021] [Indexed: 05/19/2023]
Abstract
Phytopathogenic bacteria inject effector proteins into plant host cells to promote disease. Plant resistance (R) genes encoding nucleotide-binding leucine-rich repeat (NLR) proteins mediate the recognition of functionally and structurally diverse microbial effectors, including transcription-activator like effectors (TALEs) from the bacterial genus Xanthomonas. TALEs bind to plant promoters and transcriptionally activate either disease-promoting host susceptibility (S) genes or cell death-inducing executor-type R genes. It is perplexing that plants contain TALE-perceiving executor-type R genes in addition to NLRs that also mediate the recognition of TALE-containing xanthomonads. We present recent findings on the evolvability of TALEs, which suggest that the native function of executors is not in plant immunity, but possibly in the regulation of developmentally controlled programmed cell death (PCD) processes.
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Affiliation(s)
- Moritz K Nowack
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium; VIB Center of Plant Systems Biology, 9052 Ghent, Belgium.
| | - Danalyn R Holmes
- University of Tübingen, ZMBP - General Genetics, Auf der Morgenstelle 32, 72076 Tuebingen, Germany
| | - Thomas Lahaye
- University of Tübingen, ZMBP - General Genetics, Auf der Morgenstelle 32, 72076 Tuebingen, Germany.
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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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Ji Z, Guo W, Chen X, Wang C, Zhao K. Plant Executor Genes. Int J Mol Sci 2022; 23:ijms23031524. [PMID: 35163443 PMCID: PMC8835739 DOI: 10.3390/ijms23031524] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 01/14/2022] [Accepted: 01/26/2022] [Indexed: 12/28/2022] Open
Abstract
Executor (E) genes comprise a new type of plant resistance (R) genes, identified from host-Xanthomonas interactions. The Xanthomonas-secreted transcription activation-like effectors (TALEs) usually function as major virulence factors, which activate the expression of the so-called "susceptibility" (S) genes for disease development. This activation is achieved via the binding of the TALEs to the effector-binding element (EBE) in the S gene promoter. However, host plants have evolved EBEs in the promoters of some otherwise silent R genes, whose expression directly causes a host cell death that is characterized by a hypersensitive response (HR). Such R genes are called E genes because they trap the pathogen TALEs in order to activate expression, and the resulting HR prevents pathogen growth and disease development. Currently, deploying E gene resistance is becoming a major component in disease resistance breeding, especially for rice bacterial blight resistance. Currently, the biochemical mechanisms, or the working pathways of the E proteins, are still fuzzy. There is no significant nucleotide sequence homology among E genes, although E proteins share some structural motifs that are probably associated with the signal transduction in the effector-triggered immunity. Here, we summarize the current knowledge regarding TALE-type avirulence proteins, E gene activation, the E protein structural traits, and the classification of E genes, in order to sharpen our understanding of the plant E genes.
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Affiliation(s)
- Zhiyuan Ji
- National Key Facility for Crop Gene Resources and Genetic Improvement (NFCRI), Institute of Crop Sciences, Chinese Academy of Agriculture Sciences (CAAS), Beijing 100081, China;
- Correspondence: (Z.J.); (K.Z.); Tel.: +86-10-82108751 (Z.J. & K.Z.)
| | - Wei Guo
- College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004, China; (W.G.); (X.C.)
| | - Xifeng Chen
- College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004, China; (W.G.); (X.C.)
| | - Chunlian Wang
- National Key Facility for Crop Gene Resources and Genetic Improvement (NFCRI), Institute of Crop Sciences, Chinese Academy of Agriculture Sciences (CAAS), Beijing 100081, China;
| | - Kaijun Zhao
- National Key Facility for Crop Gene Resources and Genetic Improvement (NFCRI), Institute of Crop Sciences, Chinese Academy of Agriculture Sciences (CAAS), Beijing 100081, China;
- Correspondence: (Z.J.); (K.Z.); Tel.: +86-10-82108751 (Z.J. & K.Z.)
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8
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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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9
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An SQ, Potnis N, Dow M, Vorhölter FJ, He YQ, Becker A, Teper D, Li Y, Wang N, Bleris L, Tang JL. Mechanistic insights into host adaptation, virulence and epidemiology of the phytopathogen Xanthomonas. FEMS Microbiol Rev 2020; 44:1-32. [PMID: 31578554 PMCID: PMC8042644 DOI: 10.1093/femsre/fuz024] [Citation(s) in RCA: 117] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 09/29/2019] [Indexed: 01/15/2023] Open
Abstract
Xanthomonas is a well-studied genus of bacterial plant pathogens whose members cause a variety of diseases in economically important crops worldwide. Genomic and functional studies of these phytopathogens have provided significant understanding of microbial-host interactions, bacterial virulence and host adaptation mechanisms including microbial ecology and epidemiology. In addition, several strains of Xanthomonas are important as producers of the extracellular polysaccharide, xanthan, used in the food and pharmaceutical industries. This polymer has also been implicated in several phases of the bacterial disease cycle. In this review, we summarise the current knowledge on the infection strategies and regulatory networks controlling virulence and adaptation mechanisms from Xanthomonas species and discuss the novel opportunities that this body of work has provided for disease control and plant health.
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Affiliation(s)
- Shi-Qi An
- National Biofilms Innovation Centre (NBIC), Biological Sciences, University of Southampton, University Road, Southampton SO17 1BJ, UK
| | - Neha Potnis
- Department of Entomology and Plant Pathology, Rouse Life Science Building, Auburn University, Auburn AL36849, USA
| | - Max Dow
- School of Microbiology, Food Science & Technology Building, University College Cork, Cork T12 K8AF, Ireland
| | | | - Yong-Qiang 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
| | - Anke Becker
- Loewe Center for Synthetic Microbiology and Department of Biology, Philipps-Universität Marburg, Hans-Meerwein-Straße 6, Marburg 35032, Germany
| | - Doron Teper
- Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, 700 Experiment Station Road, Lake Alfred 33850, USA
| | - Yi Li
- Bioengineering Department, University of Texas at Dallas, 2851 Rutford Ave, Richardson, TX 75080, USA.,Center for Systems Biology, University of Texas at Dallas, 800 W Campbell Road, Richardson, TX 75080, USA
| | - Nian Wang
- Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, 700 Experiment Station Road, Lake Alfred 33850, USA
| | - Leonidas Bleris
- Bioengineering Department, University of Texas at Dallas, 2851 Rutford Ave, Richardson, TX 75080, USA.,Center for Systems Biology, University of Texas at Dallas, 800 W Campbell Road, Richardson, TX 75080, USA.,Department of Biological Sciences, University of Texas at Dallas, 800 W Campbell Road, Richardson, TX75080, USA
| | - Ji-Liang 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
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10
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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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11
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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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12
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Abstract
Approaches to manipulating disease resistance in plants is expanding exponentially due to advances in our understanding of plant defense mechanisms and new tools for manipulating the plant genome. The application of effective strategies is only limited now by adoption of rapid classical genetic techniques and the acceptance of genetically engineered traits for some problems. The use of genome editing and cis-genetics, where possible, may facilitate applications that otherwise require considerable time or genetic engineering, depending on settling legal definitions of the products. Nonetheless, the variety of approaches to developing disease resistance has never been greater.
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Affiliation(s)
- Anuj Sharma
- Department of Plant Pathology, University of Florida, Gainesville, FL, USA
| | - Jeffrey B. Jones
- Department of Plant Pathology, University of Florida, Gainesville, FL, USA
| | - Frank F. White
- Department of Plant Pathology, University of Florida, Gainesville, FL, USA
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13
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Roeschlin RA, Uviedo F, García L, Molina MC, Favaro MA, Chiesa MA, Tasselli S, Franco‐Zorrilla JM, Forment J, Gadea J, Marano MR. PthA4 AT , a 7.5-repeats transcription activator-like (TAL) effector from Xanthomonas citri ssp. citri, triggers citrus canker resistance. MOLECULAR PLANT PATHOLOGY 2019; 20:1394-1407. [PMID: 31274237 PMCID: PMC6792138 DOI: 10.1111/mpp.12844] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Transcription activator-like effectors (TALEs) are important effectors of Xanthomonas spp. that manipulate the transcriptome of the host plant, conferring susceptibility or resistance to bacterial infection. Xanthomonas citri ssp. citri variant AT (X. citri AT ) triggers a host-specific hypersensitive response (HR) that suppresses citrus canker development. However, the bacterial effector that elicits this process is unknown. In this study, we show that a 7.5-repeat TALE is responsible for triggering the HR. PthA4AT was identified within the pthA repertoire of X. citri AT followed by assay of the effects on different hosts. The mode of action of PthA4AT was characterized using protein-binding microarrays and testing the effects of deletion of the nuclear localization signals and activation domain on plant responses. PthA4AT is able to bind DNA and activate transcription in an effector binding element-dependent manner. Moreover, HR requires PthA4AT nuclear localization, suggesting the activation of executor resistance (R) genes in host and non-host plants. This is the first case where a TALE of unusually short length performs a biological function by means of its repeat domain, indicating that the action of these effectors to reprogramme the host transcriptome following nuclear localization is not limited to 'classical' TALEs.
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Affiliation(s)
- Roxana Andrea Roeschlin
- Instituto de Biología Molecular y Celular de Rosario (IBR)‐Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET)Ocampo y Esmeralda S/NS2002LRKRosarioArgentina
- Área Virología, Facultad de Ciencias Bioquímicas y FarmacéuticasUniversidad Nacional de Rosario (UNR)Suipacha 590S2002LRKRosarioArgentina
- Present address:
Facultad de Ciencias AgropecuariasUniversidad Católica de Santa FeLudueña 612S3560DYRSanta FeArgentina
| | - Facundo Uviedo
- Instituto de Biología Molecular y Celular de Rosario (IBR)‐Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET)Ocampo y Esmeralda S/NS2002LRKRosarioArgentina
| | - Lucila García
- Instituto de Biología Molecular y Celular de Rosario (IBR)‐Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET)Ocampo y Esmeralda S/NS2002LRKRosarioArgentina
| | - María Celeste Molina
- Instituto de Biología Molecular y Celular de Rosario (IBR)‐Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET)Ocampo y Esmeralda S/NS2002LRKRosarioArgentina
- Área Virología, Facultad de Ciencias Bioquímicas y FarmacéuticasUniversidad Nacional de Rosario (UNR)Suipacha 590S2002LRKRosarioArgentina
| | - María Alejandra Favaro
- Instituto de Biología Molecular y Celular de Rosario (IBR)‐Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET)Ocampo y Esmeralda S/NS2002LRKRosarioArgentina
- Present address:
Facultad de Ciencias AgrariasUniversidad Nacional del Litoral, Producción VegetalKreder 2805, 3080 HOF EsperanzaSanta FeArgentina
| | - María Amalia Chiesa
- Instituto de Biología Molecular y Celular de Rosario (IBR)‐Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET)Ocampo y Esmeralda S/NS2002LRKRosarioArgentina
- Present address:
Laboratorio de Fisiología VegetalInstituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR)‐UNR/CONICETParque Villarino S/N2125Zavalla, Santa FeArgentina
| | - Sabrina Tasselli
- Instituto de Biología Molecular y Celular de Rosario (IBR)‐Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET)Ocampo y Esmeralda S/NS2002LRKRosarioArgentina
| | - José Manuel Franco‐Zorrilla
- Unidad Genómica, Centro Nacional de Biotecnología (CNB)‐Consejo Superior de Investigaciones Científicas (CSIC)Darwin 328049MadridEspaña
| | - Javier Forment
- Instituto de Biología Molecular y Celular de Plantas (IBMCP)Universidad Politécnica de Valencia‐CSICIngeniero Fausto Elio S/N.46022ValenciaEspaña
| | - José Gadea
- Instituto de Biología Molecular y Celular de Plantas (IBMCP)Universidad Politécnica de Valencia‐CSICIngeniero Fausto Elio S/N.46022ValenciaEspaña
| | - María Rosa Marano
- Instituto de Biología Molecular y Celular de Rosario (IBR)‐Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET)Ocampo y Esmeralda S/NS2002LRKRosarioArgentina
- Área Virología, Facultad de Ciencias Bioquímicas y FarmacéuticasUniversidad Nacional de Rosario (UNR)Suipacha 590S2002LRKRosarioArgentina
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14
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Krönauer C, Kilian J, Strauß T, Stahl M, Lahaye T. Cell Death Triggered by the YUCCA-like Bs3 Protein Coincides with Accumulation of Salicylic Acid and Pipecolic Acid But Not of Indole-3-Acetic Acid. PLANT PHYSIOLOGY 2019; 180:1647-1659. [PMID: 31068387 PMCID: PMC6752908 DOI: 10.1104/pp.18.01576] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 04/29/2019] [Indexed: 06/09/2023]
Abstract
The pepper (Capsicum annuum) resistance gene bacterial spot3 (Bs3) is transcriptionally activated by the matching Xanthomonas euvesicatoria transcription-activator-like effector (TALE) AvrBs3. AvrBs3-induced Bs3 expression triggers a rapid and local cell death reaction, the hypersensitive response (HR). Bs3 is most closely related to plant flavin monooxygenases of the YUCCA (YUC) family, which catalyze the final step in auxin biosynthesis. Targeted mutagenesis of predicted NADPH- and FAD-cofactor sites resulted in Bs3 derivatives that no longer trigger HR, thereby suggesting that the enzymatic activity of Bs3 is crucial to Bs3-triggered HR. Domain swap experiments between pepper Bs3 and Arabidopsis (Arabidopsis thaliana) YUC8 uncovered functionally exchangeable and functionally distinct regions in both proteins, which is in agreement with a model whereby Bs3 evolved from an ancestral YUC gene. Mass spectrometric measurements revealed that expression of YUCs, but not expression of Bs3, coincides with an increase in auxin levels, suggesting that Bs3 and YUCs, despite their sequence similarity, catalyze distinct enzymatic reactions. Finally, we found that expression of Bs3 coincides with increased levels of the salicylic acid and pipecolic acid, two compounds that are involved in systemic acquired resistance.
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Affiliation(s)
- Christina Krönauer
- Center for Plant Molecular Biology, Eberhard-Karls-University Tuebingen, Tuebingen 72076, Germany
| | - Joachim Kilian
- Center for Plant Molecular Biology, Eberhard-Karls-University Tuebingen, Tuebingen 72076, Germany
| | - Tina Strauß
- Integrated Plant Genetics, Inc., Gainesville, Florida 32653
- Genetics, Faculty of Biology, Ludwig-Maximilians-University, D-82152 Munich Martinsried, Germany
| | - Mark Stahl
- Center for Plant Molecular Biology, Eberhard-Karls-University Tuebingen, Tuebingen 72076, Germany
| | - Thomas Lahaye
- Center for Plant Molecular Biology, Eberhard-Karls-University Tuebingen, Tuebingen 72076, Germany
- Genetics, Faculty of Biology, Ludwig-Maximilians-University, D-82152 Munich Martinsried, Germany
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15
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Gochez AM, Huguet-Tapia JC, Minsavage GV, Shantaraj D, Jalan N, Strauß A, Lahaye T, Wang N, Canteros BI, Jones JB, Potnis N. Pacbio sequencing of copper-tolerant Xanthomonas citri reveals presence of a chimeric plasmid structure and provides insights into reassortment and shuffling of transcription activator-like effectors among X. citri strains. BMC Genomics 2018; 19:16. [PMID: 29301493 PMCID: PMC5755412 DOI: 10.1186/s12864-017-4408-9] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Accepted: 12/21/2017] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Xanthomonas citri, a causal agent of citrus canker, has been a well-studied model system due to recent availability of whole genome sequences of multiple strains from different geographical regions. Major limitations in our understanding of the evolution of pathogenicity factors in X. citri strains sequenced by short-read sequencing methods have been tracking plasmid reshuffling among strains due to inability to accurately assign reads to plasmids, and analyzing repeat regions among strains. X. citri harbors major pathogenicity determinants, including variable DNA-binding repeat region containing Transcription Activator-like Effectors (TALEs) on plasmids. The long-read sequencing method, PacBio, has allowed the ability to obtain complete and accurate sequences of TALEs in xanthomonads. We recently sequenced Xanthomonas citri str. Xc-03-1638-1-1, a copper tolerant A group strain isolated from grapefruit in 2003 from Argentina using PacBio RS II chemistry. We analyzed plasmid profiles, copy number and location of TALEs in complete genome sequences of X. citri strains. RESULTS We utilized the power of long reads obtained by PacBio sequencing to enable assembly of a complete genome sequence of strain Xc-03-1638-1-1, including sequences of two plasmids, 249 kb (plasmid harboring copper resistance genes) and 99 kb (pathogenicity plasmid containing TALEs). The pathogenicity plasmid in this strain is a hybrid plasmid containing four TALEs. Due to the intriguing nature of this pathogenicity plasmid with Tn3-like transposon association, repetitive elements and multiple putative sites for origins of replication, we might expect alternative structures of this plasmid in nature, illustrating the strong adaptive potential of X. citri strains. Analysis of the pathogenicity plasmid among completely sequenced X. citri strains, coupled with Southern hybridization of the pathogenicity plasmids, revealed clues to rearrangements of plasmids and resulting reshuffling of TALEs among strains. CONCLUSIONS We demonstrate in this study the importance of long-read sequencing for obtaining intact sequences of TALEs and plasmids, as well as for identifying rearrangement events including plasmid reshuffling. Rearrangement events, such as the hybrid plasmid in this case, could be a frequent phenomenon in the evolution of X. citri strains, although so far it is undetected due to the inability to obtain complete plasmid sequences with short-read sequencing methods.
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Affiliation(s)
- Alberto M Gochez
- Citrus Pathology, INTA EEA Bella Vista, Bella Vista, Corrientes, Argentina
| | | | - Gerald V Minsavage
- Department of Plant Pathology, University of Florida, Gainesville, FL, USA
| | - Deepak Shantaraj
- Department of Plant Pathology, University of Florida, Gainesville, FL, USA
| | - Neha Jalan
- Citrus Research and Education Center, Department of Microbiology and Cell Science, IFAS, University of Florida, Lake Alfred, FL, USA
| | - Annett Strauß
- University of Tübingen, ZMBP - General Genetics, Tuebingen, Germany
| | - Thomas Lahaye
- University of Tübingen, ZMBP - General Genetics, Tuebingen, Germany
| | - Nian Wang
- Citrus Research and Education Center, Department of Microbiology and Cell Science, IFAS, University of Florida, Lake Alfred, FL, USA
| | - Blanca I Canteros
- Citrus Pathology, INTA EEA Bella Vista, Bella Vista, Corrientes, Argentina
| | - Jeffrey B Jones
- Department of Plant Pathology, University of Florida, Gainesville, FL, USA.
| | - Neha Potnis
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL, 36830, USA.
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