1
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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. [PMID: 38995679 DOI: 10.1111/tpj.16929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [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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Ijaz U, Zhao C, Shabala S, Zhou M. Molecular Basis of Plant-Pathogen Interactions in the Agricultural Context. BIOLOGY 2024; 13:421. [PMID: 38927301 PMCID: PMC11200688 DOI: 10.3390/biology13060421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2024] [Revised: 06/03/2024] [Accepted: 06/03/2024] [Indexed: 06/28/2024]
Abstract
Biotic stressors pose significant threats to crop yield, jeopardizing food security and resulting in losses of over USD 220 billion per year by the agriculture industry. Plants activate innate defense mechanisms upon pathogen perception and invasion. The plant immune response comprises numerous concerted steps, including the recognition of invading pathogens, signal transduction, and activation of defensive pathways. However, pathogens have evolved various structures to evade plant immunity. Given these facts, genetic improvements to plants are required for sustainable disease management to ensure global food security. Advanced genetic technologies have offered new opportunities to revolutionize and boost plant disease resistance against devastating pathogens. Furthermore, targeting susceptibility (S) genes, such as OsERF922 and BnWRKY70, through CRISPR methodologies offers novel avenues for disrupting the molecular compatibility of pathogens and for introducing durable resistance against them in plants. Here, we provide a critical overview of advances in understanding disease resistance mechanisms. The review also critically examines management strategies under challenging environmental conditions and R-gene-based plant genome-engineering systems intending to enhance plant responses against emerging pathogens. This work underscores the transformative potential of modern genetic engineering practices in revolutionizing plant health and crop disease management while emphasizing the importance of responsible application to ensure sustainable and resilient agricultural systems.
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Affiliation(s)
- Usman Ijaz
- Tasmanian Institute of Agriculture, University of Tasmania, Launceston, TAS 7250, Australia; (U.I.); (C.Z.)
| | - Chenchen Zhao
- Tasmanian Institute of Agriculture, University of Tasmania, Launceston, TAS 7250, Australia; (U.I.); (C.Z.)
| | - Sergey Shabala
- School of Biological Science, University of Western Australia, Crawley, WA 6009, Australia;
- International Research Centre for Environmental Membrane Biology, Foshan University, Foshan 528000, China
| | - Meixue Zhou
- Tasmanian Institute of Agriculture, University of Tasmania, Launceston, TAS 7250, Australia; (U.I.); (C.Z.)
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3
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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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4
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He L, Liu P, Mei L, Luo H, Ban T, Chen X, Ma B. Disease resistance features of the executor R gene Xa7 reveal novel insights into the interaction between rice and Xanthomonas oryzae pv. oryzae. FRONTIERS IN PLANT SCIENCE 2024; 15:1365989. [PMID: 38633460 PMCID: PMC11021754 DOI: 10.3389/fpls.2024.1365989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Accepted: 03/14/2024] [Indexed: 04/19/2024]
Abstract
Bacterial blight (BB), caused by Xanthomonas oryzae pv. oryzae (Xoo), is a widespread and destructive disease in rice production. Previously, we cloned an executor R gene, Xa7, which confers durable and broad-spectrum resistance to BB. Here, we further confirmed that the transcription activator-like effector (TALE) AvrXa7 in Xoo strains could directly bind to the effector-binding element (EBE) in the promoter of the Xa7 gene. Other executor R genes (Xa7, Xa10, Xa23, and Xa27) driven by the promoter of the Xa7 gene could be activated by AvrXa7 and trigger the hypersensitive response (HR) in tobacco leaves. When the expression of the Xa23 gene was driven by the Xa7 promoter, the transgenic rice plants displayed a similar resistance spectrum as the Xa7 gene, demonstrating that the disease resistance characteristics of executor R genes are mainly determined by their induction patterns. Xa7 gene is induced locally by Xoo in the infected leaves, and its induction not only inhibited the growth of incompatible strains but also enhanced the resistance of rice plants to compatible strains, which overcame the shortcomings of its race-specific resistance. Transcriptome analysis of the Xa7 gene constitutive expression in rice plants displayed that Xa7-mediated disease resistance was related to the biosynthesis of lignin and thus enhanced resistance to Xoo. Overall, our results provided novel insights and important resources for further clarifying the molecular mechanisms of the executor R genes.
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Affiliation(s)
| | | | | | | | | | - Xifeng Chen
- College of Life Sciences, Zhejiang Normal University, Jinhua, China
| | - Bojun Ma
- College of Life Sciences, Zhejiang Normal University, Jinhua, China
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Gallas N, Li X, von Roepenack‐Lahaye E, Schandry N, Jiang Y, Wu D, Lahaye T. An ancient cis-element targeted by Ralstonia solanacearum TALE-like effectors facilitates the development of a promoter trap that could confer broad-spectrum wilt resistance. PLANT BIOTECHNOLOGY JOURNAL 2024; 22:602-616. [PMID: 37870975 PMCID: PMC10893940 DOI: 10.1111/pbi.14208] [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: 04/27/2023] [Revised: 09/25/2023] [Accepted: 10/06/2023] [Indexed: 10/25/2023]
Abstract
Ralstonia solanacearum, a species complex of bacterial plant pathogens that causes bacterial wilt, comprises four phylotypes that evolved when a founder population was split during the continental drift ~180 million years ago. Each phylotype contains strains with RipTAL proteins structurally related to transcription activator-like (TAL) effectors from the bacterial pathogen Xanthomonas. RipTALs have evolved in geographically separated phylotypes and therefore differ in sequence and potentially functionality. Earlier work has shown that phylotype I RipTAL Brg11 targets a 17-nucleotide effector binding element (EBE) and transcriptionally activates the downstream arginine decarboxylase (ADC) gene. The predicted DNA binding preferences of Brg11 and RipTALs from other phylotypes are similar, suggesting that most, if not all, RipTALs target the Brg11-EBE motif and activate downstream ADC genes. Here we show that not only phylotype I RipTAL Brg11 but also RipTALs from other phylotypes activate host genes when preceded by the Brg11-EBE motif. Furthermore, we show that Brg11 and RipTALs from other phylotypes induce the same quantitative changes of ADC-dependent plant metabolites, suggesting that most, if not all, RipTALs induce functionally equivalent changes in host cells. Finally, we report transgenic tobacco lines in which the RipTAL-binding motif Brg11-EBE mediates RipTAL-dependent transcription of the executor-type resistance (R) gene Bs4C from pepper, thereby conferring resistance to RipTAL-delivering R. solanacearum strains. Our results suggest that cell death-inducing executor-type R genes, preceded by the RipTAL-binding motif Brg11-EBE, could be used to genetically engineer broad-spectrum bacterial wilt resistance in crop plants without any apparent fitness penalty.
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Affiliation(s)
- Niels Gallas
- Allgemeine Genetik, Zentrum für Molekularbiologie der Pflanzen (ZMBP)Eberhard‐Karls‐Universität TübingenTübingenGermany
| | - Xiaoxu Li
- Technology Center, China Tobacco Hunan Industrial Co., Ltd.ChangshaChina
- Present address:
Beijing Life Science AcademyBeijingChina
| | - Edda von Roepenack‐Lahaye
- Analytik‐Zentrale Einheiten, Zentrum für Molekularbiologie der Pflanzen (ZMBP)Eberhard‐Karls‐Universität TübingenTübingenGermany
| | - Niklas Schandry
- Genetics, Department of BiologyLudwig‐Maximilians‐University MunichMartinsriedGermany
| | - Yuxin Jiang
- Hunan Key Laboratory of Plant Functional Genomics and Developmental Regulation, College of BiologyHunan UniversityChangshaChina
| | - Dousheng Wu
- Hunan Key Laboratory of Plant Functional Genomics and Developmental Regulation, College of BiologyHunan UniversityChangshaChina
| | - Thomas Lahaye
- Allgemeine Genetik, Zentrum für Molekularbiologie der Pflanzen (ZMBP)Eberhard‐Karls‐Universität TübingenTübingenGermany
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6
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Tian D, Teo J, Yin Z. Ectopic Expression of the Executor-Type R Gene Paralog Xa27B in Rice Leads to Spontaneous Lesions and Enhanced Disease Resistance. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2024; 37:143-154. [PMID: 38381127 DOI: 10.1094/mpmi-10-23-0153-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: 02/22/2024]
Abstract
Plant disease resistance (R) gene-mediated effector-triggered immunity (ETI) is usually associated with hypersensitive response (HR) and provides robust and race-specific disease resistance against pathogenic infection. The activation of ETI and HR in plants is strictly regulated, and improper activation will lead to cell death. Xa27 is an executor-type R gene in rice induced by the TAL effector AvrXa27 and confers disease resistance to Xanthomonas oryzae pv. oryzae (Xoo). Here we reported the characterization of a transgenic line with lesion mimic phenotype, designated as Spotted leaf and resistance 1 (Slr1), which was derived from rice transformation with a genomic subclone located 5,125 bp downstream of the Xa27 gene. Slr1 develops spontaneous lesions on its leaves caused by cell death and confers disease resistance to both Xoo and Xanthomonas oryzae pv. oryzicola. Further investigation revealed that the Slr1 phenotype resulted from the ectopic expression of an Xa27 paralog gene, designated as Xa27B, in the inserted DNA fragment at the Slr1 locus driven by a truncated CaMV35Sx2 promoter in reverse orientation. Disease evaluation of IRBB27, IR24, and Xa27B mutants with Xoo strains expressing dTALE-Xa27B confirmed that Xa27B is a functional executor-type R gene. The functional XA27B-GFP protein was localized to the endoplasmic reticulum and apoplast. The identification of Xa27B as a new functional executor-type R gene provides additional genetic resources for studying the mechanism of executor-type R protein-mediated ETI and developing enhanced and broad-spectrum disease resistance to Xoo through promoter engineering. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Affiliation(s)
- Dongsheng Tian
- Temasek Life Sciences Laboratory, National University of Singapore, Singapore 117604, Republic of Singapore
| | - Joanne Teo
- Temasek Life Sciences Laboratory, National University of Singapore, Singapore 117604, Republic of Singapore
| | - Zhongchao Yin
- Temasek Life Sciences Laboratory, National University of Singapore, Singapore 117604, Republic of Singapore
- Department of Biological Sciences, National University of Singapore, Singapore 117543, Republic of Singapore
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7
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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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8
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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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9
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Pérez-Quintero AL, Rodriguez-R LM, Cuesta-Morrondo S, Hakalová E, Betancurt-Anzola D, Valera LCC, Cardenas LAC, Matiz-Céron L, Jacobs JM, Roman-Reyna V, Muñoz AR, Giraldo AJB, Koebnik R. Comparative Genomics Identifies Conserved and Variable TAL Effectors in African Strains of the Cotton Pathogen Xanthomonas citri pv. malvacearum. PHYTOPATHOLOGY 2023; 113:1387-1393. [PMID: 37081724 DOI: 10.1094/phyto-12-22-0477-sc] [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
Strains of Xanthomonas citri pv. malvacearum cause bacterial blight of cotton, a potentially serious threat to cotton production worldwide, including in sub-Saharan countries. Development of disease symptoms, such as water soaking, has been linked to the activity of a class of type 3 effectors, called transcription activator-like (TAL) effectors, which induce susceptibility genes in the host's cells. To gain further insight into the global diversity of the pathogen, to elucidate their repertoires of TAL effector genes, and to better understand the evolution of these genes in the cotton-pathogenic xanthomonads, we sequenced the genomes of three African strains of X. citri pv. malvacearum using nanopore technology. We show that the cotton-pathogenic pathovar of X. citri is a monophyletic lineage containing at least three distinct genetic subclades, which appear to be mirrored by their repertoires of TAL effectors. We observed an atypical level of TAL effector gene pseudogenization, which might be related to resistance genes that are deployed to control the disease. Our work thus contributes to a better understanding of the conservation and importance of TAL effectors in the interaction with the host plant, which can inform strategies for improving resistance against bacterial blight in cotton.
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Affiliation(s)
- Alvaro L Pérez-Quintero
- Plant Health Institute of Montpellier (PHIM), University of Montpellier, CIRAD, INRAE, Institut Agro, IRD, Montpellier, France
| | - Luis M Rodriguez-R
- Department of Microbiology and Digital Science Center (DiSC), University of Innsbruck, Innsbruck, Austria
| | - Sara Cuesta-Morrondo
- Departamento de Protección Vegetal, Laboratorio Bacteriología, Centro Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA/CSIC), 28040, Madrid, Spain
- Departamento de Biotecnología-Biología Vegetal, Escuela Técnica Superior de Ingeniería Agronómica, Alimentaria y de Biosistemas, Universidad Politécnica de Madrid, 28040 Madrid, Spain
| | | | - Daniela Betancurt-Anzola
- Universidad de Los Andes, Bogotá, Colombia
- Max Planck Tandem Group in Computational Biology, Department of Biological Sciences, Universidad de los Andes, Bogotá, Colombia
| | - Laura Carolina Camelo Valera
- Universidad de Los Andes, Bogotá, Colombia
- Max Planck Tandem Group in Computational Biology, Department of Biological Sciences, Universidad de los Andes, Bogotá, Colombia
| | - Luis Alberto Chica Cardenas
- Universidad de Los Andes, Bogotá, Colombia
- Max Planck Tandem Group in Computational Biology, Department of Biological Sciences, Universidad de los Andes, Bogotá, Colombia
| | - Luisa Matiz-Céron
- Universidad de Los Andes, Bogotá, Colombia
- Max Planck Tandem Group in Computational Biology, Department of Biological Sciences, Universidad de los Andes, Bogotá, Colombia
| | - 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
| | - 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
| | - Alejandro Reyes Muñoz
- Universidad de Los Andes, Bogotá, Colombia
- Max Planck Tandem Group in Computational Biology, Department of Biological Sciences, Universidad de los Andes, Bogotá, Colombia
| | | | - Ralf Koebnik
- Plant Health Institute of Montpellier (PHIM), University of Montpellier, CIRAD, INRAE, Institut Agro, IRD, Montpellier, France
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10
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Li J, Shi X, Wang C, Li Q, Lu J, Zeng D, Xie J, Shi Y, Zhai W, Zhou Y. Genome-Wide Association Study Identifies Resistance Loci for Bacterial Blight in a Collection of Asian Temperate Japonica Rice Germplasm. Int J Mol Sci 2023; 24:ijms24108810. [PMID: 37240156 DOI: 10.3390/ijms24108810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 04/29/2023] [Accepted: 05/12/2023] [Indexed: 05/28/2023] Open
Abstract
Growing resistant rice cultivars is the most effective strategy to control bacterial blight (BB), a devastating disease caused by Xanthomonas oryzae pv. oryzae (Xoo). Screening resistant germplasm and identifying resistance (R) genes are prerequisites for breeding resistant rice cultivars. We conducted a genome-wide association study (GWAS) to detect quantitative trait loci (QTL) associated with BB resistance using 359 East Asian temperate Japonica accessions inoculated with two Chinese Xoo strains (KS6-6 and GV) and one Philippine Xoo strain (PXO99A). Based on the 55K SNPs Array dataset of the 359 Japonica accessions, eight QTL were identified on rice chromosomes 1, 2, 4, 10, and 11. Four of the QTL coincided with previously reported QTL, and four were novel loci. Six R genes were localized in the qBBV-11.1, qBBV-11.2, and qBBV-11.3 loci on chromosome 11 in this Japonica collection. Haplotype analysis revealed candidate genes associated with BB resistance in each QTL. Notably, LOC_Os11g47290 in qBBV-11.3, encoding a leucine-rich repeat receptor-like kinase, was a candidate gene associated with resistance to the virulent strain GV. Knockout mutants of Nipponbare with the susceptible haplotype of LOC_Os11g47290 exhibited significantly improved BB resistance. These results will be useful for cloning BB resistance genes and breeding resistant rice cultivars.
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Affiliation(s)
- Jianmin Li
- National Key Facility for Crop Gene Resources and Genetic Improvement/Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
- National Nanfan Research Institute (Sanya), Chinese Academy of Agricultural Sciences, Sanya 572024, China
| | - Xiaorong Shi
- College of Agronomy, Anhui Agricultural University, Hefei 230036, China
| | - Chunchao Wang
- National Key Facility for Crop Gene Resources and Genetic Improvement/Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Quanlin Li
- Institute of Genetics and Developmental Biological, Chinese Academy of Sciences, No. 1 Beichen West Road, Chaoyang District, Beijing 100101, China
| | - Jialing Lu
- National Key Facility for Crop Gene Resources and Genetic Improvement/Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Dan Zeng
- National Key Facility for Crop Gene Resources and Genetic Improvement/Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Junping Xie
- College of Agronomy, Anhui Agricultural University, Hefei 230036, China
| | - Yingyao Shi
- College of Agronomy, Anhui Agricultural University, Hefei 230036, China
| | - Wenxue Zhai
- Institute of Genetics and Developmental Biological, Chinese Academy of Sciences, No. 1 Beichen West Road, Chaoyang District, Beijing 100101, China
| | - Yongli Zhou
- National Key Facility for Crop Gene Resources and Genetic Improvement/Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
- National Nanfan Research Institute (Sanya), Chinese Academy of Agricultural Sciences, Sanya 572024, China
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11
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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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12
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Schenstnyi K, Strauß A, Dressel A, Morbitzer R, Wunderlich M, Andrade AG, Phan TTT, Aguilera PDLA, Brancato C, Berendzen KW, Lahaye T. The tomato resistance gene Bs4 suppresses leaf watersoaking phenotypes induced by AvrHah1, a transcription activator-like effector from tomato-pathogenic xanthomonads. THE NEW PHYTOLOGIST 2022; 236:1856-1870. [PMID: 36056465 DOI: 10.1111/nph.18456] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 08/19/2022] [Indexed: 06/15/2023]
Abstract
The Xanthomonas transcription activator-like effector (TALE) protein AvrBs3 transcriptionally activates the executor-type resistance (R) gene Bs3 from pepper (Capsicum annuum), thereby triggering a hypersensitive cell death reaction (HR). AvrBs3 also triggers an HR in tomato (Solanum lycopersicum) upon recognition by the nucleotide-binding leucine-rich repeat (NLR) R protein Bs4. Whether the executor-type R protein Bs3 and the NLR-type R protein Bs4 use common or distinct signalling components to trigger an HR remains unclear. CRISPR/Cas9-mutagenesis revealed, that the immune signalling node EDS1 is required for Bs4- but not for Bs3-dependent HR, suggesting that NLR- and executor-type R proteins trigger an HR via distinct signalling pathways. CRISPR/Cas9-mutagenesis also revealed that tomato Bs4 suppresses the virulence function of both TALEs, the HR-inducing AvrBs3 protein and of AvrHah1, a TALE that does not trigger an HR in tomato. Analysis of AvrBs3- and AvrHah1-induced host transcripts and disease phenotypes in CRISPR/Cas9-induced bs4 mutant plants indicates that both TALEs target orthologous transcription factor genes to promote disease in tomato and pepper host plants. Our studies display that tomato mutants lacking the TALE-sensing Bs4 protein provide a novel platform to either uncover TALE-induced disease phenotypes or genetically dissect components of executor-triggered HR.
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Affiliation(s)
- Kyrylo Schenstnyi
- University of Tübingen, ZMBP - General Genetics, Auf der Morgenstelle 32, 72076, Tuebingen, Germany
| | - Annett Strauß
- University of Tübingen, ZMBP - General Genetics, Auf der Morgenstelle 32, 72076, Tuebingen, Germany
| | - Angela Dressel
- University of Tübingen, ZMBP - General Genetics, Auf der Morgenstelle 32, 72076, Tuebingen, Germany
| | - Robert Morbitzer
- University of Tübingen, ZMBP - General Genetics, Auf der Morgenstelle 32, 72076, Tuebingen, Germany
| | - Markus Wunderlich
- University of Tübingen, ZMBP - General Genetics, Auf der Morgenstelle 32, 72076, Tuebingen, Germany
| | - Ana Gabriela Andrade
- University of Tübingen, ZMBP - General Genetics, Auf der Morgenstelle 32, 72076, Tuebingen, Germany
| | - Trang-Thi-Thu Phan
- University of Tübingen, ZMBP - General Genetics, Auf der Morgenstelle 32, 72076, Tuebingen, Germany
| | | | - Caterina Brancato
- University of Tübingen, ZMBP - Central Facilities, Auf der Morgenstelle 32, 72076, Tuebingen, Germany
| | - Kenneth Wayne Berendzen
- University of Tübingen, ZMBP - Central Facilities, 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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13
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Liu C, Zhang J, Wang J, Liu W, Wang K, Chen X, Wen Y, Tian S, Pu Y, Fan G, Ma X, Sun X. Tobacco mosaic virus hijacks its coat protein-interacting protein IP-L to inhibit NbCML30, a calmodulin-like protein, to enhance its infection. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2022; 112:677-693. [PMID: 36087000 DOI: 10.1111/tpj.15972] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2022] [Revised: 09/06/2022] [Accepted: 09/08/2022] [Indexed: 06/15/2023]
Abstract
Calcium is an important plant immune signal that is essential for activating host resistance, but how RNA viruses manipulate calcium signals to promote their infections remains largely unknown. Here, we demonstrated that tobacco mosaic virus (TMV) coat protein (CP)-interacting protein L (IP-L) associates with calmodulin-like protein 30 (NbCML30) in the cytoplasm and nucleus, and can suppress its expression at the nucleic acid and protein levels. NbCML30, which lacks the EF-hand conserved domain and cannot bind to Ca2+ , was located in the cytoplasm and nucleus and was downregulated by TMV infection. NbCML30 silencing promoted TMV infection, while its overexpression inhibited TMV infection by activating Ca2+ -dependent oxidative stress in plants. NbCML30-mediated resistance to TMV mainly depends on IP-L regulation as the facilitation of TMV infection by silencing NbCML30 was canceled by co-silencing NbCML30 and IP-L. Overall, these findings indicate that in the absence of any reported silencing suppressor activity, TMV CP manipulates IP-L to inhibit NbCML30, influencing its Ca2+ -dependent role in the oxidative stress response. These results lay a theoretical foundation that will enable us to engineer tobacco (Nicotiana spp.) with improved TMV resistance in the future.
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Affiliation(s)
- Changyun Liu
- Chongqing Key Laboratory of Plant Disease Biology, College of Plant Protection, Southwest University, Chongqing, 400716, People's Republic of China
| | - Jian Zhang
- Chongqing Key Laboratory of Plant Disease Biology, College of Plant Protection, Southwest University, Chongqing, 400716, People's Republic of China
| | - Jing Wang
- Chongqing Key Laboratory of Plant Disease Biology, College of Plant Protection, Southwest University, Chongqing, 400716, People's Republic of China
| | - Weina Liu
- Chongqing Key Laboratory of Plant Disease Biology, College of Plant Protection, Southwest University, Chongqing, 400716, People's Republic of China
| | - Ke Wang
- Chongqing Key Laboratory of Plant Disease Biology, College of Plant Protection, Southwest University, Chongqing, 400716, People's Republic of China
| | - Xue Chen
- Chongqing Key Laboratory of Plant Disease Biology, College of Plant Protection, Southwest University, Chongqing, 400716, People's Republic of China
| | - Yuxia Wen
- Chongqing Key Laboratory of Plant Disease Biology, College of Plant Protection, Southwest University, Chongqing, 400716, People's Republic of China
| | - Shaorui Tian
- Chongqing Key Laboratory of Plant Disease Biology, College of Plant Protection, Southwest University, Chongqing, 400716, People's Republic of China
| | - Yundan Pu
- Chongqing Key Laboratory of Plant Disease Biology, College of Plant Protection, Southwest University, Chongqing, 400716, People's Republic of China
| | - Guangjin Fan
- Chongqing Key Laboratory of Plant Disease Biology, College of Plant Protection, Southwest University, Chongqing, 400716, People's Republic of China
| | - Xiaozhou Ma
- Chongqing Key Laboratory of Plant Disease Biology, College of Plant Protection, Southwest University, Chongqing, 400716, People's Republic of China
| | - Xianchao Sun
- Chongqing Key Laboratory of Plant Disease Biology, College of Plant Protection, Southwest University, Chongqing, 400716, People's Republic of China
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14
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Tang Y, Wang C, Wang F, Li M, Fang Y, Ji Z, Zhao K. Development of Designer Transcription Activator-Like Effector-Based Plant Growth Regulator for Higher Yield in Rice. FRONTIERS IN PLANT SCIENCE 2022; 13:924645. [PMID: 35774805 PMCID: PMC9237611 DOI: 10.3389/fpls.2022.924645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 05/19/2022] [Indexed: 06/15/2023]
Abstract
Recent studies have shown that reprogramming of gene expression in a genome can induce the production of proteins enabling yield increase. The transcription activator-like effectors (TALEs) from several species of bacterial Xanthomonas have been extensively studied, and a series of research tools, such as genome editing tool TALENs and gene expression activators, have been developed based on the specific protein-nucleic acid recognition and binding mechanisms of TALEs. In this proof-of-principle study, we designed and constructed a designer TALE (dTALE), designated as dTALE-NOG1, to specifically target the promoter of OsNOG1 gene in rice, and demonstrated that this dTALE can be used as a new type of plant growth regulator for better crop growth and harvest. In doing so, the dTALE-NOG1 was transferred into the non-pathogenic Xanthomonas oryzae pv. oryzae (Xoo) strain PH to generate a genetically engineered bacteria (GEB) strain called PH-dtNOG1. Functional verification showed that dTALE-NOG1 could significantly induce the expression of OsNOG1. By spraying cell suspension of PH-dtNOG1 on the rice plants during the tillering stage, the transcription level of OsNOG1 was highly enhanced, the grain number of rice plants was increased by more than 11.40%, and the grain yield per plant increased by more than 11.08%, demonstrating that the dTALE-NOG1 was highly effective in enhancing rice yield. This work provided a new strategy for manipulating agronomical traits by reprogramming gene expression in a crop genome.
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Affiliation(s)
- Yongchao Tang
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Chunlian Wang
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Fujun Wang
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
- Rice Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou, China
| | - Man Li
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yanli Fang
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Zhiyuan Ji
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Kaijun Zhao
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
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15
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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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16
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Xu X, Chen Y, Li B, Zhang Z, Qin G, Chen T, Tian S. Molecular mechanisms underlying multi-level defense responses of horticultural crops to fungal pathogens. HORTICULTURE RESEARCH 2022; 9:uhac066. [PMID: 35591926 PMCID: PMC9113409 DOI: 10.1093/hr/uhac066] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 03/07/2022] [Indexed: 05/21/2023]
Abstract
The horticultural industry helps to enrich and improve the human diet while contributing to growth of the agricultural economy. However, fungal diseases of horticultural crops frequently occur during pre- and postharvest periods, reducing yields and crop quality and causing huge economic losses and wasted food. Outcomes of fungal diseases depend on both horticultural plant defense responses and fungal pathogenicity. Plant defense responses are highly sophisticated and are generally divided into preformed and induced defense responses. Preformed defense responses include both physical barriers and phytochemicals, which are the first line of protection. Induced defense responses, which include innate immunity (pattern-triggered immunity and effector-triggered immunity), local defense responses, and systemic defense signaling, are triggered to counterstrike fungal pathogens. Therefore, to develop regulatory strategies for horticultural plant resistance, a comprehensive understanding of defense responses and their underlying mechanisms is critical. Recently, integrated multi-omics analyses, CRISPR-Cas9-based gene editing, high-throughput sequencing, and data mining have greatly contributed to identification and functional determination of novel phytochemicals, regulatory factors, and signaling molecules and their signaling pathways in plant resistance. In this review, research progress on defense responses of horticultural crops to fungal pathogens and novel regulatory strategies to regulate induction of plant resistance are summarized, and then the problems, challenges, and future research directions are examined.
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Affiliation(s)
- Xiaodi Xu
- Key Laboratory of Plant Resources, Institute of Botany, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing 100093, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yong Chen
- Key Laboratory of Plant Resources, Institute of Botany, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing 100093, China
| | - Boqiang Li
- Key Laboratory of Plant Resources, Institute of Botany, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing 100093, China
| | - Zhanquan Zhang
- Key Laboratory of Plant Resources, Institute of Botany, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing 100093, China
| | - Guozheng Qin
- Key Laboratory of Plant Resources, Institute of Botany, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing 100093, China
| | - Tong Chen
- Key Laboratory of Plant Resources, Institute of Botany, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing 100093, China
- Corresponding authors. E-mail: ;
| | - Shiping Tian
- Key Laboratory of Plant Resources, Institute of Botany, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing 100093, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
- Corresponding authors. E-mail: ;
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