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Fu Q, Chen T, Wang Y, Zhou H, Zhang K, Zheng R, Zhang Y, Liu R, Yin X, Liu G, Xu Y. Plasmopara viticola effector PvCRN20 represses the import of VvDEG5 into chloroplasts to suppress immunity in grapevine. THE NEW PHYTOLOGIST 2024; 243:2311-2331. [PMID: 39091140 DOI: 10.1111/nph.20002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Accepted: 07/03/2024] [Indexed: 08/04/2024]
Abstract
Chloroplasts play a crucial role in plant defense against pathogens, making them primary targets for pathogen effectors that suppress host immunity. This study characterizes the Plasmopara viticola CRN-like effector, PvCRN20, which interacts with DEG5 in the cytoplasm but not with its interacting protein, DEG8, which is located in the chloroplast. By transiently overexpressing in tobacco leaves, we show that PvCRN20 could inhibit INF1- and Bax-triggered cell death. Constitutive expression of PvCRN20 suppresses the accumulation of reactive oxygen species (ROS) and promotes pathogen colonization. PvCRN20 reduces DEG5 entry into chloroplasts, thereby disrupting DEG5 and DEG8 interactions in chloroplasts. Overexpression of VvDEG5 and VvDEG8 induces ROS accumulation and enhances grapevine resistance to P. viticola, whereas knockout of VvDEG8 represses ROS production and promotes P. viticola colonization. Consistently, ectopic expression of VvDEG5 and VvDEG8 in tobacco promotes chloroplast-derived ROS accumulation, whereas co-expression of PvCRN20 counteracted this promotion by VvDEG5. Therefore, DEG5 is essential for the virulence function of PvCRN20. Although PvCRN20 is located in both the nucleus and cytoplasm, only cytoplasmic PvCRN20 suppresses plant immunity and promotes pathogen infection. Our results reveal that PvCRN20 dampens plant defenses by repressing the chloroplast import of DEG5, thus reducing host ROS accumulation and facilitating pathogen colonization.
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Affiliation(s)
- Qingqing Fu
- State Key Laboratory of Crop Stress Resistance and High-Efficiency Production, College of Horticulture, Northwest A&F University, Yangling, Shaanxi, 712100, China
- Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Tingting Chen
- College of Agricultural Science, Xichang University, Xichang, 615000, China
| | - Yunlei Wang
- State Key Laboratory of Crop Stress Resistance and High-Efficiency Production, College of Horticulture, Northwest A&F University, Yangling, Shaanxi, 712100, China
- Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Huixuan Zhou
- State Key Laboratory of Crop Stress Resistance and High-Efficiency Production, College of Horticulture, Northwest A&F University, Yangling, Shaanxi, 712100, China
- Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Kangzhuang Zhang
- State Key Laboratory of Crop Stress Resistance and High-Efficiency Production, College of Horticulture, Northwest A&F University, Yangling, Shaanxi, 712100, China
- Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Runlong Zheng
- State Key Laboratory of Crop Stress Resistance and High-Efficiency Production, College of Horticulture, Northwest A&F University, Yangling, Shaanxi, 712100, China
- Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Yanan Zhang
- State Key Laboratory of Crop Stress Resistance and High-Efficiency Production, College of Horticulture, Northwest A&F University, Yangling, Shaanxi, 712100, China
- Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Ruiqi Liu
- State Key Laboratory of Crop Stress Resistance and High-Efficiency Production, College of Horticulture, Northwest A&F University, Yangling, Shaanxi, 712100, China
- Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Xiao Yin
- State Key Laboratory of Crop Stress Resistance and High-Efficiency Production, College of Horticulture, Northwest A&F University, Yangling, Shaanxi, 712100, China
- Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Guotian Liu
- State Key Laboratory of Crop Stress Resistance and High-Efficiency Production, College of Horticulture, Northwest A&F University, Yangling, Shaanxi, 712100, China
- Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Yan Xu
- State Key Laboratory of Crop Stress Resistance and High-Efficiency Production, College of Horticulture, Northwest A&F University, Yangling, Shaanxi, 712100, China
- Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Northwest A&F University, Yangling, Shaanxi, 712100, China
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2
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Nguyen QM, Iswanto ABB, Kang H, Moon J, Phan KAT, Son GH, Suh MC, Chung EH, Gassmann W, Kim SH. The processed C-terminus of AvrRps4 effector suppresses plant immunity via targeting multiple WRKYs. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2024; 66:1769-1787. [PMID: 38869289 DOI: 10.1111/jipb.13710] [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: 10/11/2023] [Revised: 05/03/2024] [Accepted: 05/04/2024] [Indexed: 06/14/2024]
Abstract
Pathogens generate and secrete effector proteins to the host plant cells during pathogenesis to promote virulence and colonization. If the plant carries resistance (R) proteins that recognize pathogen effectors, effector-triggered immunity (ETI) is activated, resulting in a robust immune response and hypersensitive response (HR). The bipartite effector AvrRps4 from Pseudomonas syringae pv. pisi has been well studied in terms of avirulence function. In planta, AvrRps4 is processed into two parts. The C-terminal fragment of AvrRps4 (AvrRps4C) induces HR in turnip and is recognized by the paired resistance proteins AtRRS1/AtRPS4 in Arabidopsis. Here, we show that AvrRps4C targets a group of Arabidopsis WRKY, including WRKY46, WRKY53, WRKY54, and WRKY70, to induce its virulence function. Indeed, AvrRps4C suppresses the general binding and transcriptional activities of immune-positive regulator WRKY54 and WRKY54-mediated resistance. AvrRps4C interferes with WRKY54's binding activity to target gene SARD1 in vitro, suggesting WRKY54 is sequestered from the SARD1 promoter by AvrRps4C. Through the interaction of AvrRps4C with four WRKYs, AvrRps4 enhances the formation of homo-/heterotypic complexes of four WRKYs and sequesters them in the cytoplasm, thus inhibiting their function in plant immunity. Together, our results provide a detailed virulence mechanism of AvrRps4 through its C-terminus.
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Affiliation(s)
- Quang-Minh Nguyen
- Division of Applied Life Science (BK21 Four Program), Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju, 52828, Korea
| | - Arya Bagus Boedi Iswanto
- Division of Applied Life Science (BK21 Four Program), Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju, 52828, Korea
| | - Hobin Kang
- Division of Applied Life Science (BK21 Four Program), Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju, 52828, Korea
| | - Jiyun Moon
- Division of Applied Life Science (BK21 Four Program), Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju, 52828, Korea
| | - Kieu Anh Thi Phan
- Division of Applied Life Science (BK21 Four Program), Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju, 52828, Korea
| | - Geon Hui Son
- Division of Applied Life Science (BK21 Four Program), Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju, 52828, Korea
| | - Mi Chung Suh
- Department of Life Science, Sogang University, Seoul, 04107, Korea
| | - Eui-Hwan Chung
- Department of Plant Biotechnology, Korea University, Seoul, 02841, Korea
| | - Walter Gassmann
- Division of Plant Science and Technology, Christopher S. Bond Life Sciences Center and Interdisciplinary Plant Group, University of Missouri, Columbia, 65211, Missouri, USA
| | - Sang Hee Kim
- Division of Applied Life Science (BK21 Four Program), Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju, 52828, Korea
- Division of Life Science and Research Institute of Molecular Alchemy, Gyeongsang National University, Jinju, 52828, Korea
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Lee YT, Senturk M, Guan Y, Wang MC. Bacteria-organelle communication in physiology and disease. J Cell Biol 2024; 223:e202310134. [PMID: 38748249 PMCID: PMC11096858 DOI: 10.1083/jcb.202310134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 04/03/2024] [Accepted: 05/03/2024] [Indexed: 05/18/2024] Open
Abstract
Bacteria, omnipresent in our environment and coexisting within our body, exert dual beneficial and pathogenic influences. These microorganisms engage in intricate interactions with the human body, impacting both human health and disease. Simultaneously, certain organelles within our cells share an evolutionary relationship with bacteria, particularly mitochondria, best known for their energy production role and their dynamic interaction with each other and other organelles. In recent years, communication between bacteria and mitochondria has emerged as a new mechanism for regulating the host's physiology and pathology. In this review, we delve into the dynamic communications between bacteria and host mitochondria, shedding light on their collaborative regulation of host immune response, metabolism, aging, and longevity. Additionally, we discuss bacterial interactions with other organelles, including chloroplasts, lysosomes, and the endoplasmic reticulum (ER).
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Affiliation(s)
- Yi-Tang Lee
- Waisman Center, University of Wisconsin, Madison, WI, USA
- Huffington Center on Aging, Baylor College of Medicine, Houston, TX, USA
- Integrative Program of Molecular and Biochemical Sciences, Baylor College of Medicine, Houston, TX, USA
| | - Mumine Senturk
- Huffington Center on Aging, Baylor College of Medicine, Houston, TX, USA
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX, USA
| | - Youchen Guan
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Meng C. Wang
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX, USA
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
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4
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Stojilković B, Xiang H, Chen Y, Maulana MI, Bauters L, Van de Put H, Steppe K, Liao J, de Almeida Engler J, Gheysen G. The nematode effector Mj-NEROSs interacts with Rieske's iron-sulfur protein influencing plastid ROS production to suppress plant immunity. THE NEW PHYTOLOGIST 2024; 242:2787-2802. [PMID: 38693568 DOI: 10.1111/nph.19781] [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: 12/16/2022] [Accepted: 03/16/2024] [Indexed: 05/03/2024]
Abstract
Root-knot nematodes (RKN; Meloidogyne species) are plant pathogens that introduce several effectors in their hosts to facilitate infection. The actual targets and functioning mechanism of these effectors largely remain unexplored. This study illuminates the role and interplay of the Meloidogyne javanica nematode effector ROS suppressor (Mj-NEROSs) within the host plant environment. Mj-NEROSs suppresses INF1-induced cell death as well as flg22-induced callose deposition and reactive oxygen species (ROS) production. A transcriptome analysis highlighted the downregulation of ROS-related genes upon Mj-NEROSs expression. NEROSs interacts with the plant Rieske's iron-sulfur protein (ISP) as shown by yeast-two-hybrid and bimolecular fluorescence complementation. Secreted from the subventral pharyngeal glands into giant cells, Mj-NEROSs localizes in the plastids where it interacts with ISP, subsequently altering electron transport rates and ROS production. Moreover, our results demonstrate that isp Arabidopsis thaliana mutants exhibit increased susceptibility to M. javanica, indicating ISP importance for plant immunity. The interaction of a nematode effector with a plastid protein highlights the possible role of root plastids in plant defense, prompting many questions on the details of this process.
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Affiliation(s)
- Boris Stojilković
- Department of Biotechnology, Ghent University, Proeftuinstraat 86, Ghent, 9000, Belgium
- Cell and Developmental Biology, John Innes Centre, Norwich, NR4 7UH, UK
| | - Hui Xiang
- Department of Biotechnology, Ghent University, Proeftuinstraat 86, Ghent, 9000, Belgium
| | - Yujin Chen
- Department of Biotechnology, Ghent University, Proeftuinstraat 86, Ghent, 9000, Belgium
| | - Muhammad Iqbal Maulana
- Laboratory of Nematology, Wageningen University, Droevendaalsesteeg 1, 6708 PB, Wageningen, the Netherlands
- Department of Plant Protection, Faculty of Agriculture, Universitas Gadjah Mada, Jl. Flora, Bulaksumur, Yogyakarta, 55281, Indonesia
| | - Lander Bauters
- Department of Biotechnology, Ghent University, Proeftuinstraat 86, Ghent, 9000, Belgium
| | - Hans Van de Put
- Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, 9000, Gent, Belgium
| | - Kathy Steppe
- Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, 9000, Gent, Belgium
| | - Jinling Liao
- Laboratory of Plant Nematology, South China Agricultural University, Guangzhou, 510642, China
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, 510642, China
- Guangdong Vocational College of Ecological Engineering, Guangzhou, 510520, China
| | | | - Godelieve Gheysen
- Department of Biotechnology, Ghent University, Proeftuinstraat 86, Ghent, 9000, Belgium
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5
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Horton KN, Gassmann W. Greater than the sum of their parts: an overview of the AvrRps4 effector family. FRONTIERS IN PLANT SCIENCE 2024; 15:1400659. [PMID: 38799092 PMCID: PMC11116571 DOI: 10.3389/fpls.2024.1400659] [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: 03/14/2024] [Accepted: 04/26/2024] [Indexed: 05/29/2024]
Abstract
Phytopathogenic microbes use secreted effector proteins to increase their virulence in planta. If these effectors or the results of their activity are detected by the plant cell, the plant will mount an immune response which applies evolutionary pressure by reducing growth and success of the pathogen. Bacterial effector proteins in the AvrRps4 family (AvrRps4, HopK1, and XopO) have commonly been used as tools to investigate plant immune components. At the same time, the in planta functions of this family of effectors have yet to be fully characterized. In this minireview we summarize current knowledge about the AvrRps4 effector family with emphasis on properties of the proteins themselves. We hypothesize that the HopK1 C-terminus and the AvrRps4 C-terminus, though unrelated in sequence and structure, are broadly related in functions that counteract plant defense responses.
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Affiliation(s)
| | - Walter Gassmann
- Division of Plant Science and Technology, Bond Life Sciences Center, and Interdisciplinary Plant Group, University of Missouri, Columbia, MO, United States
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6
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Ji Z, Wang M, Zhang S, Du Y, Cong J, Yan H, Guo H, Xu B, Zhou Z. GDSL Esterase/Lipase GELP1 Involved in the Defense of Apple Leaves against Colletotrichum gloeosporioides Infection. Int J Mol Sci 2023; 24:10343. [PMID: 37373491 DOI: 10.3390/ijms241210343] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 06/07/2023] [Accepted: 06/16/2023] [Indexed: 06/29/2023] Open
Abstract
GDSL esterases/lipases are a subclass of lipolytic enzymes that play critical roles in plant growth and development, stress response, and pathogen defense. However, the GDSL esterase/lipase genes involved in the pathogen response of apple remain to be identified and characterized. Thus, in this study, we aimed to analyze the phenotypic difference between the resistant variety, Fuji, and susceptible variety, Gala, during infection with C. gloeosporioides, screen for anti-disease-associated proteins in Fuji leaves, and elucidate the underlying mechanisms. The results showed that GDSL esterase/lipase protein GELP1 contributed to C. gloeosporioides infection defense in apple. During C. gloeosporioides infection, GELP1 expression was significantly upregulated in Fuji. Fuji leaves exhibited a highly resistant phenotype compared with Gala leaves. The formation of infection hyphae of C. gloeosporioides was inhibited in Fuji. Moreover, recombinant His:GELP1 protein suppressed hyphal formation during infection in vitro. Transient expression in Nicotiana benthamiana showed that GELP1-eGFP localized to the endoplasmic reticulum and chloroplasts. GELP1 overexpression in GL-3 plants increased resistance to C. gloeosporioides. MdWRKY15 expression was upregulated in the transgenic lines. Notably, GELP1 transcript levels were elevated in GL-3 after salicylic acid treatment. These results suggest that GELP1 increases apple resistance to C. gloeosporioides by indirectly regulating salicylic acid biosynthesis.
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Affiliation(s)
- Zhirui Ji
- College of Plant Protection, Gansu Agricultural University, Lanzhou 730070, China
- Research Institute of Pomology, Chinese Academy of Agricultural Sciences, Xingcheng 125100, China
| | - Meiyu Wang
- Research Institute of Pomology, Chinese Academy of Agricultural Sciences, Xingcheng 125100, China
| | - Shuwu Zhang
- College of Plant Protection, Gansu Agricultural University, Lanzhou 730070, China
| | - Yinan Du
- Research Institute of Pomology, Chinese Academy of Agricultural Sciences, Xingcheng 125100, China
| | - Jialin Cong
- Research Institute of Pomology, Chinese Academy of Agricultural Sciences, Xingcheng 125100, China
| | - Haifeng Yan
- Research Institute of Pomology, Chinese Academy of Agricultural Sciences, Xingcheng 125100, China
| | - Haimeng Guo
- Research Institute of Pomology, Chinese Academy of Agricultural Sciences, Xingcheng 125100, China
| | - Bingliang Xu
- College of Plant Protection, Gansu Agricultural University, Lanzhou 730070, China
| | - Zongshan Zhou
- Research Institute of Pomology, Chinese Academy of Agricultural Sciences, Xingcheng 125100, China
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7
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Lovelace AH, Dorhmi S, Hulin MT, Li Y, Mansfield JW, Ma W. Effector Identification in Plant Pathogens. PHYTOPATHOLOGY 2023; 113:637-650. [PMID: 37126080 DOI: 10.1094/phyto-09-22-0337-kd] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Effectors play a central role in determining the outcome of plant-pathogen interactions. As key virulence proteins, effectors are collectively indispensable for disease development. By understanding the virulence mechanisms of effectors, fundamental knowledge of microbial pathogenesis and disease resistance have been revealed. Effectors are also considered double-edged swords because some of them activate immunity in disease resistant plants after being recognized by specific immune receptors, which evolved to monitor pathogen presence or activity. Characterization of effector recognition by their cognate immune receptors and the downstream immune signaling pathways is instrumental in implementing resistance. Over the past decades, substantial research effort has focused on effector biology, especially concerning their interactions with virulence targets or immune receptors in plant cells. A foundation of this research is robust identification of the effector repertoire from a given pathogen, which depends heavily on bioinformatic prediction. In this review, we summarize methodologies that have been used for effector mining in various microbial pathogens which use different effector delivery mechanisms. We also discuss current limitations and provide perspectives on how recently developed analytic tools and technologies may facilitate effector identification and hence generation of a more complete vision of host-pathogen interactions. [Formula: see text] Copyright © 2023 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)
| | - Sara Dorhmi
- The Sainsbury Laboratory, Norwich, NR4 7UH, U.K
- Department of Microbiology and Plant Pathology, University of California Riverside, CA 92521, U.S.A
| | | | - Yufei Li
- The Sainsbury Laboratory, Norwich, NR4 7UH, U.K
| | - John W Mansfield
- Faculty of Natural Sciences, Imperial College London, London, SW7 2BX, U.K
| | - Wenbo Ma
- The Sainsbury Laboratory, Norwich, NR4 7UH, U.K
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8
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Breen S, McLellan H, Birch PRJ, Gilroy EM. Tuning the Wavelength: Manipulation of Light Signaling to Control Plant Defense. Int J Mol Sci 2023; 24:ijms24043803. [PMID: 36835216 PMCID: PMC9958957 DOI: 10.3390/ijms24043803] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 02/06/2023] [Accepted: 02/09/2023] [Indexed: 02/17/2023] Open
Abstract
The growth-defense trade-off in plants is a phenomenon whereby plants must balance the allocation of their resources between developmental growth and defense against attack by pests and pathogens. Consequently, there are a series of points where growth signaling can negatively regulate defenses and where defense signaling can inhibit growth. Light perception by various photoreceptors has a major role in the control of growth and thus many points where it can influence defense. Plant pathogens secrete effector proteins to manipulate defense signaling in their hosts. Evidence is emerging that some of these effectors target light signaling pathways. Several effectors from different kingdoms of life have converged on key chloroplast processes to take advantage of regulatory crosstalk. Moreover, plant pathogens also perceive and react to light in complex ways to regulate their own growth, development, and virulence. Recent work has shown that varying light wavelengths may provide a novel way of controlling or preventing disease outbreaks in plants.
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Affiliation(s)
- Susan Breen
- Division of Plant Sciences, University of Dundee, At James Hutton Institute, Errol Road, Invergowrie, Dundee DD2 5DA, UK
| | - Hazel McLellan
- Division of Plant Sciences, University of Dundee, At James Hutton Institute, Errol Road, Invergowrie, Dundee DD2 5DA, UK
| | - Paul R. J. Birch
- Division of Plant Sciences, University of Dundee, At James Hutton Institute, Errol Road, Invergowrie, Dundee DD2 5DA, UK
- Cell and Molecular Sciences, James Hutton Institute, Errol Road, Invergowrie, Dundee DD2 5DA, UK
| | - Eleanor M. Gilroy
- Cell and Molecular Sciences, James Hutton Institute, Errol Road, Invergowrie, Dundee DD2 5DA, UK
- Correspondence: ; Tel.: +44-1382568827
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9
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Li C, Wang L, Cseke LJ, Vasconcelos F, Huguet-Tapia JC, Gassmann W, Pauwels L, White FF, Dong H, Yang B. Efficient CRISPR-Cas9 based cytosine base editors for phytopathogenic bacteria. Commun Biol 2023; 6:56. [PMID: 36646768 PMCID: PMC9842757 DOI: 10.1038/s42003-023-04451-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Accepted: 01/10/2023] [Indexed: 01/18/2023] Open
Abstract
Phytopathogenic bacteria play important roles in plant productivity, and developments in gene editing have potential for enhancing the genetic tools for the identification of critical genes in the pathogenesis process. CRISPR-based genome editing variants have been developed for a wide range of applications in eukaryotes and prokaryotes. However, the unique mechanisms of different hosts restrict the wide adaptation for specific applications. Here, CRISPR-dCas9 (dead Cas9) and nCas9 (Cas9 nickase) deaminase vectors were developed for a broad range of phytopathogenic bacteria. A gene for a dCas9 or nCas9, cytosine deaminase CDA1, and glycosylase inhibitor fusion protein (cytosine base editor, or CBE) was applied to base editing under the control of different promoters. Results showed that the RecA promoter led to nearly 100% modification of the target region. When residing on the broad host range plasmid pHM1, CBERecAp is efficient in creating base edits in strains of Xanthomonas, Pseudomonas, Erwinia and Agrobacterium. CBE based on nCas9 extended the editing window and produced a significantly higher editing rate in Pseudomonas. Strains with nonsynonymous mutations in test genes displayed expected phenotypes. By multiplexing guide RNA genes, the vectors can modify up to four genes in a single round of editing. Whole-genome sequencing of base-edited isolates of Xanthomonas oryzae pv. oryzae revealed guide RNA-independent off-target mutations. Further modifications of the CBE, using a CDA1 variant (CBERecAp-A) reduced off-target effects, providing an improved editing tool for a broad group of phytopathogenic bacteria.
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Affiliation(s)
- Chenhao Li
- grid.134936.a0000 0001 2162 3504Division of Plant Science and Technology, Bond Life Sciences Center, University of Missouri, Columbia, Missouri USA ,grid.27871.3b0000 0000 9750 7019Department of Plant Pathology, Nanjing Agricultural University, Nanjing, Jiangsu P. R. China
| | - Longfei Wang
- grid.134936.a0000 0001 2162 3504Division of Plant Science and Technology, Bond Life Sciences Center, University of Missouri, Columbia, Missouri USA
| | - Leland J. Cseke
- grid.134936.a0000 0001 2162 3504Division of Plant Science and Technology, Bond Life Sciences Center, University of Missouri, Columbia, Missouri USA
| | - Fernanda Vasconcelos
- grid.134936.a0000 0001 2162 3504Division of Plant Science and Technology, Bond Life Sciences Center, University of Missouri, Columbia, Missouri USA
| | - Jose Carlos Huguet-Tapia
- grid.15276.370000 0004 1936 8091Department of Plant Pathology, University of Florida, Gainesville, Florida USA
| | - Walter Gassmann
- grid.134936.a0000 0001 2162 3504Division of Plant Science and Technology, Bond Life Sciences Center, University of Missouri, Columbia, Missouri USA
| | - Laurens Pauwels
- grid.5342.00000 0001 2069 7798Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Ghent, Belgium ,grid.511033.5Center for Plant Systems Biology, VIB, B-9052 Ghent, Belgium
| | - Frank F. White
- grid.15276.370000 0004 1936 8091Department of Plant Pathology, University of Florida, Gainesville, Florida USA
| | - Hansong Dong
- grid.27871.3b0000 0000 9750 7019Department of Plant Pathology, Nanjing Agricultural University, Nanjing, Jiangsu P. R. China
| | - Bing Yang
- grid.134936.a0000 0001 2162 3504Division of Plant Science and Technology, Bond Life Sciences Center, University of Missouri, Columbia, Missouri USA ,grid.34424.350000 0004 0466 6352Donald Danforth Plant Science Center, St. Louis, Missouri USA
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10
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Nguyen Q, Iswanto ABB, Son GH, Vuong UT, Lee J, Kang J, Gassmann W, Kim SH. AvrRps4 effector family processing and recognition in lettuce. MOLECULAR PLANT PATHOLOGY 2022; 23:1390-1398. [PMID: 35616618 PMCID: PMC9366065 DOI: 10.1111/mpp.13233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 05/06/2022] [Accepted: 05/08/2022] [Indexed: 06/15/2023]
Abstract
During pathogenesis, effector proteins are secreted from the pathogen to the host plant to provide virulence activity for invasion of the host. However, once the host plant recognizes one of the delivered effectors, effector-triggered immunity activates a robust immune and hypersensitive response (HR). In planta, the effector AvrRps4 is processed into the N-terminus (AvrRps4N ) and the C-terminus (AvrRps4C ). AvrRps4C is sufficient to trigger HR in turnip and activate AtRRS1/AtRPS4-mediated immunity in Arabidopsis; on the other hand, AvrRps4N induces HR in lettuce. Furthermore, AvrRps4N -mediated HR requires a conserved arginine at position 112 (R112), which is also important for full-length AvrRps4 (AvrRps4F ) processing. Here, we show that effector processing and effector recognition in lettuce are uncoupled for the AvrRps4 family. In addition, we compared effector recognition by lettuce of AvrRps4 and its homologues, HopK1 and XopO. Interestingly, unlike for AvrRps4 and HopK1, mutation of the conserved R111 in XopO by itself was insufficient to abolish recognition. The combination of amino acid substitutions arginine 111 to leucine with glutamate 114 to lysine abolished the XopO-mediated HR, suggesting that AvrRps4 family members have distinct structural requirements for perception by lettuce. Together, our results provide an insight into the processing and recognition of AvrRps4 and its homologues.
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Affiliation(s)
- Quang‐Minh Nguyen
- Division of Applied Life Science (BK21 Four Program), Plant Molecular Biology and Biotechnology Research CenterGyeongsang National UniversityJinjuRepublic of Korea
| | - Arya Bagus Boedi Iswanto
- Division of Applied Life Science (BK21 Four Program), Plant Molecular Biology and Biotechnology Research CenterGyeongsang National UniversityJinjuRepublic of Korea
| | - Geon Hui Son
- Division of Applied Life Science (BK21 Four Program), Plant Molecular Biology and Biotechnology Research CenterGyeongsang National UniversityJinjuRepublic of Korea
| | - Uyen Thi Vuong
- Division of Applied Life Science (BK21 Four Program), Plant Molecular Biology and Biotechnology Research CenterGyeongsang National UniversityJinjuRepublic of Korea
| | - Jihyun Lee
- Division of Applied Life Science (BK21 Four Program), Plant Molecular Biology and Biotechnology Research CenterGyeongsang National UniversityJinjuRepublic of Korea
| | - Jin‐Ho Kang
- Department of International Agricultural Technology, Institutes of Green‐bio Science and TechnologySeoul National UniversityPyeongChangRepublic of Korea
- Department of Agriculture, Forestry and Bioresources and Integrated Major in Global Smart Farm, College of Agriculture and Life SciencesSeoul National UniversitySeoulRepublic of Korea
| | - Walter Gassmann
- Division of Plant Science and Technology, Christopher S. Bond Life Sciences Center and Interdisciplinary Plant GroupUniversity of MissouriColumbiaMissouriUSA
| | - Sang Hee Kim
- Division of Applied Life Science (BK21 Four Program), Plant Molecular Biology and Biotechnology Research CenterGyeongsang National UniversityJinjuRepublic of Korea
- Division of Life ScienceGyeongsang National UniversityJinjuRepublic of Korea
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11
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Corredor-Moreno P, Badgami R, Jones S, Saunders DGO. Temporally coordinated expression of nuclear genes encoding chloroplast proteins in wheat promotes Puccinia striiformis f. sp. tritici infection. Commun Biol 2022; 5:853. [PMID: 35996019 PMCID: PMC9395331 DOI: 10.1038/s42003-022-03780-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2022] [Accepted: 07/28/2022] [Indexed: 11/09/2022] Open
Abstract
Targeting host processes that allow pathogens to thrive can be invaluable in resistance breeding. Here, we generated a deep-sequencing transcriptome time course for Puccinia striiformis f. sp. tritici (Pst) infection on wheat and compared datasets from three wheat varieties with different levels of susceptibility to two tested pathogen isolates. We sought genes specifically altered in a susceptible host as candidates that might support colonisation. Host responses differed between Pst-varietal pairs most prominently early during infection. Notably, however, nuclear genes encoding chloroplast-localised proteins (NGCPs) exhibited temporal coordination of expression profiles that differed at later time points in relation to Pst susceptibility. Disrupting one such NGCP, encoding the chloroplast-localised RNA binding protein TaCSP41a, led to lower Pst susceptibility. These analyses thus highlight NGCPs as prime targets for Pst manipulation during infection and point to TaCSP41a disruption as a potential source of Pst resistance for breeding programmes. A transcriptome time course of Puccinia striiformis f. sp. tritici (Pst) infection reveals nuclear genes encoding chloroplast-localized proteins are manipulated during infection and highlights TaCSP41a disruption as a target for resistance breeding.
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Affiliation(s)
| | | | - Sally Jones
- John Innes Centre, Norwich Research Park, Norwich, UK
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12
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Zhang B, Liu X, Sun Y, Xu L, Ren Z, Zhao Y, Han Y. Sclerospora graminicola Suppresses Plant Defense Responses by Disrupting Chlorophyll Biosynthesis and Photosynthesis in Foxtail Millet. FRONTIERS IN PLANT SCIENCE 2022; 13:928040. [PMID: 35903230 PMCID: PMC9317951 DOI: 10.3389/fpls.2022.928040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 06/24/2022] [Indexed: 06/15/2023]
Abstract
Downy mildew of foxtail millet is an important oomycete disease caused by Sclerospora graminicola, affecting the yield and quality of the crop. Foxtail millet infected with S. graminicola exhibit symptoms of leaf yellowing and leaf cracking. To uncover the pathogenic mechanism of this disease, we explored the effects on chlorophyll synthesis and photosynthesis of foxtail millet leaves infected by S. graminicola. An elite foxtail millet variety, JG21, susceptible to S. graminicola, was used as for this study. S. graminicola inhibited chlorophyll synthesis and caused loose mesophyll cell arrangement. In addition, some cells were severely vacuolated in S. graminicola-infected foxtail millet leaves at the early stages of infection. S. graminicola could invade the mesophyll cells through haustoria which destroyed the chloroplast structure at the middle stages of infection causing significant accumulation of osmiophilic particles (OPs) and disintegrated chloroplast grana lamellae. Furthermore, foxtail millet leaves split longitudinally at the later stages of infection. Chlorophyll and carotenoid contents in infected leaves decreased significantly compared with those in the control. Net photosynthetic rate (Pn) of leaves and stomatal conductance showed a downward trend, and intercellular carbon dioxide concentrations increased significantly following the infection with S. graminicola. A total of 1,618 differentially expressed genes (DEGs) were detected between the control group and the treatment groups using RNA sequencing (RNA-Seq) among S1-S5 stages. DEGs associated with "photosynthesis" and "light reaction" were enriched. Gene expression patterns showed that 91.3% of 23 genes related to chlorophyll synthesis and photosynthesis, were significantly down-regulated than the control during S1-S5 stages. Based on the gene expression dataset, weighed gene co-expression network analysis (WGCNA) with 19 gene co-expression modules related to photosynthesis revealed six hub genes related to chlorophyll synthesis, which were suppressed during infection. The results suggest that infection of S. graminicola led to weak chlorophyll synthesis and rapid chloroplasts disappearance in foxtail millet. The defense responses and resistance of foxtail millet to S. graminicola were inhibited because chloroplast structure and function were destroyed in leaves, and the sexual reproduction in S. graminicola could be completed rapidly.
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Affiliation(s)
- Baojun Zhang
- College of Plant Protection, Shanxi Agricultural University, Taiyuan, China
- Shanxi Key Laboratory of Minor Crop Germplasm Innovation and Molecular Breeding, Taiyuan, China
| | - Xu Liu
- College of Plant Protection, Shanxi Agricultural University, Taiyuan, China
| | - Yurong Sun
- College of Plant Protection, Shanxi Agricultural University, Taiyuan, China
| | - Lin Xu
- College of Agriculture, Shanxi Agricultural University, Taiyuan, China
| | - Zhixian Ren
- College of Plant Protection, Shanxi Agricultural University, Taiyuan, China
| | - Yaofei Zhao
- College of Agriculture, Shanxi Agricultural University, Taiyuan, China
- Shanxi Key Laboratory of Minor Crop Germplasm Innovation and Molecular Breeding, Taiyuan, China
| | - Yuanhuai Han
- College of Agriculture, Shanxi Agricultural University, Taiyuan, China
- Shanxi Key Laboratory of Minor Crop Germplasm Innovation and Molecular Breeding, Taiyuan, China
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13
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Li Z, Li C, Fu S, Liu Y, Xu Y, Wu J, Wang Y, Zhou X. NSvc4 Encoded by Rice Stripe Virus Targets Host Chloroplasts to Suppress Chloroplast-Mediated Defense. Viruses 2021; 14:36. [PMID: 35062239 PMCID: PMC8778898 DOI: 10.3390/v14010036] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 12/22/2021] [Accepted: 12/22/2021] [Indexed: 01/04/2023] Open
Abstract
Our previous research found that NSvc4, the movement protein of rice stripe virus (RSV), could localize to the actin filaments, endoplasmic reticulum, plasmodesmata, and chloroplast, but the roles of NSvc4 played in the chloroplast were opaque. Here, we confirm the accumulation of NSvc4 in the chloroplasts and the N-terminal 1-73 amino acids of NSvc4 are sufficient to localize to chloroplasts. We provide evidence to show that chloroplast-localized NSvc4 can impair the chloroplast-mediated immunity. Expressing NSvc4 in Nicotiana benthamiana leaves results in the decreased expression of defense-related genes NbPR1, NbPR2, and NbWRKY12 and the inhibition of chloroplast-derived ROS production. In addition, generation of an infectious clone of potato virus X (PVX) carrying NSvc4 facilitates PVX infection in N. benthamiana plants. Moreover, we identify two chloroplast-related host factors, named NbGAPDH-A and NbPsbQ1, both of which can interact with NSvc4. Knockdown of NbGAPDH-A or NbPsbQ1 can both promote RSV infection. Our results decipher a detailed function of NSvc4 in the chloroplast.
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Affiliation(s)
- Zongdi Li
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China; (Z.L.); (C.L.); (S.F.); (Y.L.); (Y.X.)
| | - Chenyang Li
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China; (Z.L.); (C.L.); (S.F.); (Y.L.); (Y.X.)
| | - Shuai Fu
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China; (Z.L.); (C.L.); (S.F.); (Y.L.); (Y.X.)
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Yu Liu
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China; (Z.L.); (C.L.); (S.F.); (Y.L.); (Y.X.)
| | - Yi Xu
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China; (Z.L.); (C.L.); (S.F.); (Y.L.); (Y.X.)
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Jianxiang Wu
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China; (Z.L.); (C.L.); (S.F.); (Y.L.); (Y.X.)
| | - Yaqin Wang
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China; (Z.L.); (C.L.); (S.F.); (Y.L.); (Y.X.)
| | - Xueping Zhou
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China; (Z.L.); (C.L.); (S.F.); (Y.L.); (Y.X.)
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
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14
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Song Y, Feng L, Alyafei MAM, Jaleel A, Ren M. Function of Chloroplasts in Plant Stress Responses. Int J Mol Sci 2021; 22:ijms222413464. [PMID: 34948261 PMCID: PMC8705820 DOI: 10.3390/ijms222413464] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Revised: 12/06/2021] [Accepted: 12/13/2021] [Indexed: 12/24/2022] Open
Abstract
The chloroplast has a central position in oxygenic photosynthesis and primary metabolism. In addition to these functions, the chloroplast has recently emerged as a pivotal regulator of plant responses to abiotic and biotic stress conditions. Chloroplasts have their own independent genomes and gene-expression machinery and synthesize phytohormones and a diverse range of secondary metabolites, a significant portion of which contribute the plant response to adverse conditions. Furthermore, chloroplasts communicate with the nucleus through retrograde signaling, for instance, reactive oxygen signaling. All of the above facilitate the chloroplast’s exquisite flexibility in responding to environmental stresses. In this review, we summarize recent findings on the involvement of chloroplasts in plant regulatory responses to various abiotic and biotic stresses including heat, chilling, salinity, drought, high light environmental stress conditions, and pathogen invasions. This review will enrich the better understanding of interactions between chloroplast and environmental stresses, and will lay the foundation for genetically enhancing plant-stress acclimatization.
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Affiliation(s)
- Yun Song
- School of Life Sciences, Liaocheng University, Liaocheng 252000, China;
| | - Li Feng
- Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, Chengdu 610213, China;
- Zhengzhou Research Base, State Key Laboratory of Cotton Biology, Zhengzhou University, Zhengzhou 450001, China
| | - Mohammed Abdul Muhsen Alyafei
- Department of Integrative Agriculture, College of Agriculture and Veterinary Medicine, United Arab Emirates University, Al Ain P.O. Box 15551, United Arab Emirates; (M.A.M.A.); (A.J.)
| | - Abdul Jaleel
- Department of Integrative Agriculture, College of Agriculture and Veterinary Medicine, United Arab Emirates University, Al Ain P.O. Box 15551, United Arab Emirates; (M.A.M.A.); (A.J.)
| | - Maozhi Ren
- Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, Chengdu 610213, China;
- Zhengzhou Research Base, State Key Laboratory of Cotton Biology, Zhengzhou University, Zhengzhou 450001, China
- Correspondence: ; Tel.: +86-(13)-527313471
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15
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Samal B, Chatterjee S. Bacterial quorum sensing facilitates Xanthomonas campesteris pv. campestris invasion of host tissue to maximize disease symptoms. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:6524-6543. [PMID: 33993246 DOI: 10.1093/jxb/erab211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 05/12/2021] [Indexed: 06/12/2023]
Abstract
Quorum sensing (QS) helps the Xanthomonas group of phytopathogens to infect several crop plants. The vascular phytopathogen Xanthomonas campestris pv. campestris (Xcc) is the causal agent of black rot disease on Brassicaceae leaves, where a typical v-shaped lesion spans both vascular and mesophyll regions with progressive leaf chlorosis. Recently, the role of QS has been elucidated during Xcc early infection stages. However, a detailed insight into the possible role of QS-regulated bacterial invasion in host chlorophagy during late infection stages remains elusive. In this study, using QS-responsive whole-cell bioreporters of Xcc, we present a detailed chronology of QS-facilitated Xcc colonization in the mesophyll region of cabbage (Brassica oleracea) leaves. We report that QS-enabled localization of Xcc to parenchymal chloroplasts triggers leaf chlorosis and promotion of systemic infection. Our results indicate that the QS response in the Xanthomonas group of vascular phytopathogens maximizes their population fitness across host tissues to trigger stage-specific host chlorophagy and establish a systemic infection.
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Affiliation(s)
- Biswajit Samal
- Lab of Plant-Microbe Interactions, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, Telangana, India
- Graduate Studies, Manipal Academy of Higher Education, Manipal, Karnataka, India
| | - Subhadeep Chatterjee
- Lab of Plant-Microbe Interactions, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, Telangana, India
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16
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Xing Y, Xu N, Bhandari DD, Lapin D, Sun X, Luo X, Wang Y, Cao J, Wang H, Coaker G, Parker JE, Liu J. Bacterial effector targeting of a plant iron sensor facilitates iron acquisition and pathogen colonization. THE PLANT CELL 2021; 33:2015-2031. [PMID: 33751120 PMCID: PMC8290286 DOI: 10.1093/plcell/koab075] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 02/25/2021] [Indexed: 05/25/2023]
Abstract
Acquisition of nutrients from different species is necessary for pathogen colonization. Iron is an essential mineral nutrient for nearly all organisms, but little is known about how pathogens manipulate plant hosts to acquire iron. Here, we report that AvrRps4, an effector protein delivered by Pseudomonas syringae bacteria to plants, interacts with and targets the plant iron sensor protein BRUTUS (BTS) to facilitate iron uptake and pathogen proliferation in Arabidopsis thaliana. Infection of rps4 and eds1 by P. syringae pv. tomato (Pst) DC3000 expressing AvrRps4 resulted in iron accumulation, especially in the plant apoplast. AvrRps4 alleviates BTS-mediated degradation of bHLH115 and ILR3(IAA-Leucine resistant 3), two iron regulatory proteins. In addition, BTS is important for accumulating immune proteins Enhanced Disease Susceptibility1 (EDS1) at both the transcriptional and protein levels upon Pst (avrRps4) infections. Our findings suggest that AvrRps4 targets BTS to facilitate iron accumulation and BTS contributes to RPS4/EDS1-mediated immune responses.
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Affiliation(s)
- Yingying Xing
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ning Xu
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Deepak D Bhandari
- Department of Plant-Microbe Interactions, Max-Planck Institute for Plant Breeding Research, 50829 Cologne, Germany
- MSU-DOE Plant Research Lab, Michigan State University, East Lansing, Michigan 48824, USA
| | - Dmitry Lapin
- Department of Plant-Microbe Interactions, Max-Planck Institute for Plant Breeding Research, 50829 Cologne, Germany
- Cluster of Excellence on Plant Sciences (CEPLAS), Cologne 50829, Germany
| | - Xinhua Sun
- Department of Plant-Microbe Interactions, Max-Planck Institute for Plant Breeding Research, 50829 Cologne, Germany
| | - Xuming Luo
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yeqiong Wang
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jidong Cao
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Hongbin Wang
- Institute of Medicinal Plant Physiology and Ecology, Guangzhou University of Chinese Medicine, Guangzhou 510006, China
| | - Gitta Coaker
- Department of Plant Pathology, University of California, Davis, California 95616, USA
| | - Jane E Parker
- Department of Plant-Microbe Interactions, Max-Planck Institute for Plant Breeding Research, 50829 Cologne, Germany
- Cluster of Excellence on Plant Sciences (CEPLAS), Cologne 50829, Germany
| | - Jun Liu
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing 100049, China
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17
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Davis MM, Lamichhane R, Bruce BD. Elucidating Protein Translocon Dynamics with Single-Molecule Precision. Trends Cell Biol 2021; 31:569-583. [PMID: 33865650 DOI: 10.1016/j.tcb.2021.03.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 03/17/2021] [Accepted: 03/18/2021] [Indexed: 01/28/2023]
Abstract
Translocons are protein assemblies that facilitate the targeting and transport of proteins into and across biological membranes. Our understanding of these systems has been advanced using genetics, biochemistry, and structural biology. Despite these classic advances, until recently we have still largely lacked a detailed understanding of how translocons recognize and facilitate protein translocation. With the advent and improvements of cryogenic electron microscopy (cryo-EM) single-particle analysis and single-molecule fluorescence microscopy, the details of how translocons function are finally emerging. Here, we introduce these methods and evaluate their importance in understanding translocon structure, function, and dynamics.
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Affiliation(s)
- Madeline M Davis
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee at Knoxville, Knoxville, TN 37996, USA
| | - Rajan Lamichhane
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee at Knoxville, Knoxville, TN 37996, USA
| | - Barry D Bruce
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee at Knoxville, Knoxville, TN 37996, USA; Department of Microbiology, University of Tennessee at Knoxville, Knoxville, TN 37996, USA; Graduate Program in Genome Science and Technology, University of Tennessee at Knoxville, Knoxville, TN 37996, USA; Chemical and Biomolecular Engineering, University of Tennessee at Knoxville, Knoxville, TN 37996, USA.
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18
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Gazi AD, Kokkinidis M, Fadouloglou VE. α-Helices in the Type III Secretion Effectors: A Prevalent Feature with Versatile Roles. Int J Mol Sci 2021; 22:ijms22115412. [PMID: 34063760 PMCID: PMC8196651 DOI: 10.3390/ijms22115412] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 05/14/2021] [Accepted: 05/17/2021] [Indexed: 12/16/2022] Open
Abstract
Type III Secretion Systems (T3SSs) are multicomponent nanomachines located at the cell envelope of Gram-negative bacteria. Their main function is to transport bacterial proteins either extracellularly or directly into the eukaryotic host cell cytoplasm. Type III Secretion effectors (T3SEs), latest to be secreted T3S substrates, are destined to act at the eukaryotic host cell cytoplasm and occasionally at the nucleus, hijacking cellular processes through mimicking eukaryotic proteins. A broad range of functions is attributed to T3SEs, ranging from the manipulation of the host cell's metabolism for the benefit of the bacterium to bypassing the host's defense mechanisms. To perform this broad range of manipulations, T3SEs have evolved numerous novel folds that are compatible with some basic requirements: they should be able to easily unfold, pass through the narrow T3SS channel, and refold to an active form when on the other side. In this review, the various folds of T3SEs are presented with the emphasis placed on the functional and structural importance of α-helices and helical domains.
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Affiliation(s)
- Anastasia D. Gazi
- Unit of Technology & Service Ultrastructural Bio-Imaging (UTechS UBI), Institut Pasteur, 75015 Paris, France
- Correspondence: (A.D.G.); (V.E.F.)
| | - Michael Kokkinidis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Nikolaou Plastira 100, Heraklion, 70013 Crete, Greece;
- Department of Biology, Voutes University Campus, University of Crete, Heraklion, 70013 Crete, Greece
| | - Vasiliki E. Fadouloglou
- Department of Molecular Biology & Genetics, Democritus University of Thrace, 68100 Alexandroupolis, Greece
- Correspondence: (A.D.G.); (V.E.F.)
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19
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Schreiber KJ, Chau-Ly IJ, Lewis JD. What the Wild Things Do: Mechanisms of Plant Host Manipulation by Bacterial Type III-Secreted Effector Proteins. Microorganisms 2021; 9:1029. [PMID: 34064647 PMCID: PMC8150971 DOI: 10.3390/microorganisms9051029] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 05/03/2021] [Accepted: 05/04/2021] [Indexed: 01/05/2023] Open
Abstract
Phytopathogenic bacteria possess an arsenal of effector proteins that enable them to subvert host recognition and manipulate the host to promote pathogen fitness. The type III secretion system (T3SS) delivers type III-secreted effector proteins (T3SEs) from bacterial pathogens such as Pseudomonas syringae, Ralstonia solanacearum, and various Xanthomonas species. These T3SEs interact with and modify a range of intracellular host targets to alter their activity and thereby attenuate host immune signaling. Pathogens have evolved T3SEs with diverse biochemical activities, which can be difficult to predict in the absence of structural data. Interestingly, several T3SEs are activated following injection into the host cell. Here, we review T3SEs with documented enzymatic activities, as well as T3SEs that facilitate virulence-promoting processes either indirectly or through non-enzymatic mechanisms. We discuss the mechanisms by which T3SEs are activated in the cell, as well as how T3SEs modify host targets to promote virulence or trigger immunity. These mechanisms may suggest common enzymatic activities and convergent targets that could be manipulated to protect crop plants from infection.
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Affiliation(s)
- Karl J. Schreiber
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94710, USA; (K.J.S.); (I.J.C.-L.)
| | - Ilea J. Chau-Ly
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94710, USA; (K.J.S.); (I.J.C.-L.)
| | - Jennifer D. Lewis
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94710, USA; (K.J.S.); (I.J.C.-L.)
- Plant Gene Expression Center, United States Department of Agriculture, University of California, Berkeley, CA 94710, USA
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20
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Tzelepis G, Dölfors F, Holmquist L, Dixelius C. Plant mitochondria and chloroplasts are targeted by the Rhizoctonia solani RsCRP1 effector. Biochem Biophys Res Commun 2021; 544:86-90. [PMID: 33550013 DOI: 10.1016/j.bbrc.2021.01.019] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 01/07/2021] [Indexed: 01/10/2023]
Abstract
The fungal species Rhizoctonia solani belongs to the Basidiomycota division and is a ubiquitous soil-borne pathogen. It is the main agent of the damping-off disease in seedlings and causes the root and crown rot disease in sugar beets. Plant pathogens deploy small secreted proteins, called effectors, to manipulate plant immunity in order to infect the host. Here, a gene (RsCRP1) encoded a putative effector cysteine-rich protein was cloned, expressed in Cercospora beticola and used for virulence assays. The RsCRP1 gene was highly induced upon the early-infection stage of sugar beet seedlings and disease was promoted. Confocal microscopy demonstrated localization to the chloroplasts and mitochondria upon transient expression of RsCRP1 in leaves of Nicotiana benthamiana. Further, this effector was unable to induce necrosis or to suppress hypersensitive response induced by the Avr4/Cf4 complex in N. benthamiana. Overall, these data indicate that RsCRP1 is a novel effector targeting distinct plant cell organelles in order to facilitate a successful infection at the early stages of the disease development.
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Affiliation(s)
- Georgios Tzelepis
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Uppsala Biocenter, Box 7026, SE-750 07, Uppsala, Sweden.
| | - Fredrik Dölfors
- Swedish University of Agricultural Sciences, Department of Plant Biology, Uppsala BioCenter, Linnean Center for Plant Biology, P.O. Box 7080, S-75007, Uppsala, Sweden
| | - Louise Holmquist
- MariboHilleshög Research AB, Säbyholmsvägen 24, S-26191, Landskrona, Sweden
| | - Christina Dixelius
- Swedish University of Agricultural Sciences, Department of Plant Biology, Uppsala BioCenter, Linnean Center for Plant Biology, P.O. Box 7080, S-75007, Uppsala, Sweden
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21
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Yang F, Xiao K, Pan H, Liu J. Chloroplast: The Emerging Battlefield in Plant-Microbe Interactions. FRONTIERS IN PLANT SCIENCE 2021; 12:637853. [PMID: 33747017 PMCID: PMC7966814 DOI: 10.3389/fpls.2021.637853] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 01/28/2021] [Indexed: 05/08/2023]
Abstract
Higher plants and some algae convert the absorbed light into chemical energy through one of the most important organelles, chloroplast, for photosynthesis and store it in the form of organic compounds to supply their life activities. However, more and more studies have shown that the role of chloroplasts is more than a factory for photosynthesis. In the process of light conversion to chemical energy, any damage to the components of chloroplast may affect the photosynthesis efficiency and promote the production of by-products, reactive oxygen species, that are mainly produced in the chloroplasts. Substantial evidence show that chloroplasts are also involved in the battle of plants and microbes. Chloroplasts are important in integrating a variety of external environmental stimuli and regulate plant immune responses by transmitting signals to the nucleus and other cell compartments through retrograde signaling pathways. Besides, chloroplasts can also regulate the biosynthesis and signal transduction of phytohormones, including salicylic acid and jasmonic acid, to affect the interaction between the plants and microbes. Since chloroplasts play such an important role in plant immunity, correspondingly, chloroplasts have become the target of pathogens. Different microbial pathogens target the chloroplast and affect its functions to promote their colonization in the host plants.
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Affiliation(s)
| | | | | | - Jinliang Liu
- College of Plant Sciences, Jilin University, Changchun, China
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22
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Su J, Nguyen QM, Kimble A, Pike SM, Kim SH, Gassmann W. The Conserved Arginine Required for AvrRps4 Processing Is Also Required for Recognition of Its N-Terminal Fragment in Lettuce. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2021; 34:270-278. [PMID: 33147120 DOI: 10.1094/mpmi-10-20-0285-r] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Pathogens utilize a repertoire of effectors to facilitate pathogenesis, but when the host recognizes one of them, it causes effector-triggered immunity. The Pseudomonas type III effector AvrRps4 is a bipartite effector that is processed in planta into a functional 133-amino acid N-terminus (AvrRps4-N) and 88-amino acid C-terminus (AvrRps4-C). Previous studies found AvrRps4-C to be sufficient to trigger the hypersensitive response (HR) in turnip. In contrast, our recent work found that AvrRps4-N but not AvrRps4-C triggered HR in lettuce, whereas both were required for resistance induction in Arabidopsis. Here, we initially compared AvrRps4 recognition by turnip and lettuce using transient expression. By serial truncation, we identified the central conserved region consisting of 37 amino acids as essential for AvrRps4-N recognition, whereas the putative type III secretion signal peptide or the C-terminal 13 amino acids were dispensable. Surprisingly, the conserved arginine at position 112 (R112) that is required for full-length AvrRps4 processing is also required for the recognition of AvrRps4-N by lettuce. Mutating R112 to hydrophobic leucine or negatively charged glutamate abolished the HR-inducing capacity of AvrRps4-N, while a positively charged lysine at this position resulted in a slow and weak HR. Together, our results suggest an AvrRps4-N recognition-specific role of R112 in lettuce.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Affiliation(s)
- Jianbin Su
- Division of Plant Sciences, University of Missouri, Columbia, MO 65211, U.S.A
- Christopher S. Bond Life Sciences Center and Interdisciplinary Plant Group, University of Missouri, Columbia, MO 66211, U.S.A
| | - Quang-Minh Nguyen
- Division of Applied Life Science (BK21 Plus), Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju 52828, Korea
| | - Ashten Kimble
- Christopher S. Bond Life Sciences Center and Interdisciplinary Plant Group, University of Missouri, Columbia, MO 66211, U.S.A
- Division of Biological Sciences, University of Columbia, MO 65211, U.S.A
| | - Sharon M Pike
- Division of Plant Sciences, University of Missouri, Columbia, MO 65211, U.S.A
- Christopher S. Bond Life Sciences Center and Interdisciplinary Plant Group, University of Missouri, Columbia, MO 66211, U.S.A
| | - Sang Hee Kim
- Division of Applied Life Science (BK21 Plus), Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju 52828, Korea
| | - Walter Gassmann
- Division of Plant Sciences, University of Missouri, Columbia, MO 65211, U.S.A
- Christopher S. Bond Life Sciences Center and Interdisciplinary Plant Group, University of Missouri, Columbia, MO 66211, U.S.A
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23
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Littlejohn GR, Breen S, Smirnoff N, Grant M. Chloroplast immunity illuminated. THE NEW PHYTOLOGIST 2021; 229:3088-3107. [PMID: 33206379 DOI: 10.1111/nph.17076] [Citation(s) in RCA: 57] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 09/12/2020] [Indexed: 05/04/2023]
Abstract
The chloroplast has recently emerged as pivotal to co-ordinating plant defence responses and as a target of plant pathogens. Beyond its central position in oxygenic photosynthesis and primary metabolism - key targets in the complex virulence strategies of diverse pathogens - the chloroplast integrates, decodes and responds to environmental signals. The capacity of chloroplasts to synthesize phytohormones and a diverse range of secondary metabolites, combined with retrograde and reactive oxygen signalling, provides exquisite flexibility to both perceive and respond to biotic stresses. These processes also represent a plethora of opportunities for pathogens to evolve strategies to directly or indirectly target 'chloroplast immunity'. This review covers the contribution of the chloroplast to pathogen associated molecular pattern and effector triggered immunity as well as systemic acquired immunity. We address phytohormone modulation of immunity and surmise how chloroplast-derived reactive oxygen species underpin chloroplast immunity through indirect evidence inferred from genetic modification of core chloroplast components and direct pathogen targeting of the chloroplast. We assess the impact of transcriptional reprogramming of nuclear-encoded chloroplast genes during disease and defence and look at future research challenges.
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Affiliation(s)
- George R Littlejohn
- School of Biological and Marine Sciences, University of Plymouth, Plymouth, PL4 8AA, UK
| | - Susan Breen
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK
| | - Nicholas Smirnoff
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4QD, UK
| | - Murray Grant
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK
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24
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Han Z, Xiong D, Xu Z, Liu T, Tian C. The Cytospora chrysosperma Virulence Effector CcCAP1 Mainly Localizes to the Plant Nucleus To Suppress Plant Immune Responses. mSphere 2021; 6:e00883-20. [PMID: 33627507 PMCID: PMC8544888 DOI: 10.1128/msphere.00883-20] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 02/01/2021] [Indexed: 01/07/2023] Open
Abstract
Canker disease is caused by the fungus Cytospora chrysosperma and damages a wide range of woody plants, causing major losses to crops and native plants. Plant pathogens secrete virulence-related effectors into host cells during infection to regulate plant immunity and promote colonization. However, the functions of C. chrysosperma effectors remain largely unknown. In this study, we used Agrobacterium tumefaciens-mediated transient expression system in Nicotiana benthamiana and confocal microscopy to investigate the immunoregulation roles and subcellular localization of CcCAP1, a virulence-related effector identified in C. chrysosperma CcCAP1 was significantly induced in the early stages of infection and contains cysteine-rich secretory proteins, antigen 5, and pathogenesis-related 1 proteins (CAP) superfamily domain with four cysteines. CcCAP1 suppressed the programmed cell death triggered by Bcl-2-associated X protein (BAX) and the elicitin infestin1 (INF1) in transient expression assays with Nicotiana benthamiana The CAP superfamily domain was sufficient for its cell death-inhibiting activity and three of the four cysteines in the CAP superfamily domain were indispensable for its activity. Pathogen challenge assays in N. benthamiana demonstrated that transient expression of CcCAP1 promoted Botrytis cinerea infection and restricted reactive oxygen species accumulation, callose deposition, and defense-related gene expression. In addition, expression of green fluorescent protein-labeled CcCAP1 in N. benthamiana showed that it localized to both the plant nucleus and the cytoplasm, but the nuclear localization was essential for its full immune inhibiting activity. These results suggest that this virulence-related effector of C. chrysosperma modulates plant immunity and functions mainly via its nuclear localization and the CAP domain.IMPORTANCE The data presented in this study provide a key resource for understanding the biology and molecular basis of necrotrophic pathogen responses to Nicotiana benthamiana resistance utilizing effector proteins, and CcCAP1 may be used in future studies to understand effector-triggered susceptibility processes in the Cytospora chrysosperma-poplar interaction system.
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Affiliation(s)
- Zhu Han
- The Key Laboratory for Silviculture and Conservation of Ministry of Education, College of Forestry, Beijing Forestry University, Beijing, China
| | - Dianguang Xiong
- The Key Laboratory for Silviculture and Conservation of Ministry of Education, College of Forestry, Beijing Forestry University, Beijing, China
| | - Zhiye Xu
- The Key Laboratory for Silviculture and Conservation of Ministry of Education, College of Forestry, Beijing Forestry University, Beijing, China
| | - Tingli Liu
- Provincial Key Laboratory of Agrobiology, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Chengming Tian
- The Key Laboratory for Silviculture and Conservation of Ministry of Education, College of Forestry, Beijing Forestry University, Beijing, China
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25
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Wang J, Dhroso A, Liu X, Baum TJ, Hussey RS, Davis EL, Wang X, Korkin D, Mitchum MG. Phytonematode peptide effectors exploit a host post-translational trafficking mechanism to the ER using a novel translocation signal. THE NEW PHYTOLOGIST 2021; 229:563-574. [PMID: 32569394 DOI: 10.1111/nph.16765] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 06/02/2020] [Indexed: 05/26/2023]
Abstract
Cyst nematodes induce a multicellular feeding site within roots called a syncytium. It remains unknown how root cells are primed for incorporation into the developing syncytium. Furthermore, it is unclear how CLAVATA3/EMBRYO SURROUNDING REGION (CLE) peptide effectors secreted into the cytoplasm of the initial feeding cell could have an effect on plant cells so distant from where the nematode is feeding as the syncytium expands. Here we describe a novel translocation signal within nematode CLE effectors that is recognized by plant cell secretory machinery to redirect these peptides from the cytoplasm to the apoplast of plant cells. We show that the translocation signal is functionally conserved across CLE effectors identified in nematode species spanning three genera and multiple plant species, operative across plant cell types, and can traffic other unrelated small peptides from the cytoplasm to the apoplast of host cells via a previously unknown post-translational mechanism of endoplasmic reticulum (ER) translocation. Our results uncover a mechanism of effector trafficking that is unprecedented in any plant pathogen to date, andthey illustrate how phytonematodes can deliver effector proteins into host cells and then hijack plant cellular processes for their export back out of the cell to function as external signaling molecules to distant cells.
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Affiliation(s)
- Jianying Wang
- Division of Plant Sciences and Bond Life Sciences Center, University of Missouri, Columbia, MO, 65211, USA
| | - Andi Dhroso
- Department of Computer Science and Bioinformatics and Computational Biology Program, Worcester Polytechnic Institute, Worcester, MA, 01609, USA
| | - Xunliang Liu
- Department of Plant Pathology and Institute of Plant Breeding, Genetics, and Genomics, Center for Applied Genetic Technologies, University of Georgia, Athens, GA, 30602, USA
| | - Thomas J Baum
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA, 50011, USA
| | - Richard S Hussey
- Department of Plant Pathology, University of Georgia, Athens, GA, 30602, USA
| | - Eric L Davis
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC, 27695, USA
| | - Xiaohong Wang
- Robert W. Holley Center for Agriculture and Health, US Department of Agriculture, Agricultural Research Service and School of Integrative Plant Science, Cornell University, Ithaca, NY, 14853, USA
| | - Dmitry Korkin
- Department of Computer Science and Bioinformatics and Computational Biology Program, Worcester Polytechnic Institute, Worcester, MA, 01609, USA
| | - Melissa G Mitchum
- Division of Plant Sciences and Bond Life Sciences Center, University of Missouri, Columbia, MO, 65211, USA
- Department of Plant Pathology and Institute of Plant Breeding, Genetics, and Genomics, Center for Applied Genetic Technologies, University of Georgia, Athens, GA, 30602, USA
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26
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Tian D, Chen Z, Lin Y, Chen Z, Bui KT, Wang Z, Wang F. Weighted Gene Co-Expression Network Coupled with a Critical-Time-Point Analysis during Pathogenesis for Predicting the Molecular Mechanism Underlying Blast Resistance in Rice. RICE (NEW YORK, N.Y.) 2020; 13:81. [PMID: 33306159 PMCID: PMC7732884 DOI: 10.1186/s12284-020-00439-8] [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: 06/15/2020] [Accepted: 11/13/2020] [Indexed: 06/12/2023]
Abstract
BACKGROUND Rice blast, caused by the ascomycete fungus M. oryzae, is one of the most important diseases of rice. Although many blast resistance (R) genes have been identified and deployed in rice varieties, the molecular mechanisms responsible for the R gene-mediated defense responses are yet not fully understood. RESULTS In this study, we used comparative transcriptomic analysis to explore the molecular mechanism involved in Piz-t-mediated resistance in a transgenic line containing Piz-t (NPB-Piz-t) compared to Nipponbare (NPB). Clustering and principal component analysis (PCA) revealed that the time-point at 24-h post inoculation (hpi) was the most important factor distinguishing the four time-points, which consisted of four genes of mitogen-activated protein kinases (MAPKs) signaling pathway, one gene related to WRKY DNA-binding domain containing protein, five pathogenesis-related protein (OsPR1s) genes, and three genes of R proteins involving in the most significant protein-protein interaction (PPI) pathway. Using weighted gene co-expression network analysis (WGCNA) to investigate RNA-seq data across 0, 24, 48, and 72 hpi, nine modules with similar patterns expression pattern (SEP) and three modules with differential expression pattern (DEP) between NPB-Piz-t and NPB across 0, 24, 48, and 72 hpi with KJ201 (referred to as Piz-t-KJ201 and NPB-KJ201) were identified. Among these the most representative SEP green-yellow module is associated with photosynthesis, and DEP pink module comprised of two specific expressed nucleotide-binding domain and leucine-rich repeat (NLR) genes of LOC_Os06g17900 and LOC_Os06g17920 of Pi2/9 homologous, three NLR genes of LOC_Os11g11810, LOC_Os11g11770, and LOC_Os11g11920 which are putatively associated with important agronomic traits, and a B3 DNA binding domain containing protein related genes (LOC_Os10g39190). Knockout of LOC_Os10g39190 via CRISPR-Cas9 resulted in plant death at the seedling stage. CONCLUSIONS The research suggested that Piz-t and multiple NLR network might play important roles in the regulation of the resistance response in the Piz-t-KJ201 interaction system. The identified genes provide an NLR repository to study the rice-M. oryzae interaction system and facilitate the breeding of blast-resistant cultivars in the future.
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Affiliation(s)
- Dagang Tian
- Biotechnology Research Institute, Fujian Provincial Key Laboratory of Genetic Engineering for Agriculture, Fujian Academy of Agricultural Sciences, Fuzhou, 350003, China.
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Life Science, Fujian Agriculture and Forestry University, Fuzhou, China.
| | - Zaijie Chen
- Biotechnology Research Institute, Fujian Provincial Key Laboratory of Genetic Engineering for Agriculture, Fujian Academy of Agricultural Sciences, Fuzhou, 350003, China
| | - Yan Lin
- Biotechnology Research Institute, Fujian Provincial Key Laboratory of Genetic Engineering for Agriculture, Fujian Academy of Agricultural Sciences, Fuzhou, 350003, China
| | - Ziqiang Chen
- Biotechnology Research Institute, Fujian Provincial Key Laboratory of Genetic Engineering for Agriculture, Fujian Academy of Agricultural Sciences, Fuzhou, 350003, China
| | - Khuynh The Bui
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Zonghua Wang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Life Science, Fujian Agriculture and Forestry University, Fuzhou, China.
| | - Feng Wang
- Biotechnology Research Institute, Fujian Provincial Key Laboratory of Genetic Engineering for Agriculture, Fujian Academy of Agricultural Sciences, Fuzhou, 350003, China.
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27
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Gao F, Zhao S, Men S, Kang Z, Hong J, Wei C, Hong W, Li Y. A non-structural protein encoded by Rice Dwarf Virus targets to the nucleus and chloroplast and inhibits local RNA silencing. SCIENCE CHINA. LIFE SCIENCES 2020; 63:1703-1713. [PMID: 32303960 DOI: 10.1007/s11427-019-1648-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 02/13/2020] [Indexed: 02/08/2023]
Abstract
RNA silencing is a potent antiviral mechanism in plants and animals. As a counter-defense, many viruses studied to date encode one or more viral suppressors of RNA silencing (VSR). In the latter case, how different VSRs encoded by a virus function in silencing remains to be fully understood. We previously showed that the nonstructural protein Pns10 of a Phytoreovirus, Rice dwarf virus (RDV), functions as a VSR. Here we present evidence that another nonstructural protein, Pns11, also functions as a VSR. While Pns10 was localized in the cytoplasm, Pns11 was localized both in the nucleus and chloroplasts. Pns11 has two bipartite nuclear localization signals (NLSs), which were required for nuclear as well as chloroplastic localization. The NLSs were also required for the silencing activities of Pns11. This is the first report that multiple VSRs encoded by a virus are localized in different subcellular compartments, and that a viral protein can be targeted to both the nucleus and chloroplast. These findings may have broad significance in studying the subcellular targeting of VSRs and other viral proteins in viral-host interactions.
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Affiliation(s)
- Feng Gao
- The State Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, 100871, China
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland, 20742, USA
| | - Shanshan Zhao
- The State Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, 100871, China
- College of Plant Protection, Fujian Agriculture & Forestry University, Fuzhou, 350002, China
| | - Shuzhen Men
- College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Zhensheng Kang
- Department of Plant Protection, Northwestern Agriculture and Forestry University, Yangling, 712100, China
| | - Jian Hong
- College of Agriculture, Zhejiang University, Hangzhou, 310029, China
| | - Chunhong Wei
- The State Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, 100871, China
| | - Wei Hong
- The State Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, 100871, China.
- The First Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, 310006, China.
| | - Yi Li
- The State Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, 100871, China.
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28
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Medina-Puche L, Tan H, Dogra V, Wu M, Rosas-Diaz T, Wang L, Ding X, Zhang D, Fu X, Kim C, Lozano-Duran R. A Defense Pathway Linking Plasma Membrane and Chloroplasts and Co-opted by Pathogens. Cell 2020; 182:1109-1124.e25. [DOI: 10.1016/j.cell.2020.07.020] [Citation(s) in RCA: 76] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2019] [Revised: 04/23/2020] [Accepted: 07/15/2020] [Indexed: 12/22/2022]
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29
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Christian RW, Hewitt SL, Nelson G, Roalson EH, Dhingra A. Plastid transit peptides-where do they come from and where do they all belong? Multi-genome and pan-genomic assessment of chloroplast transit peptide evolution. PeerJ 2020; 8:e9772. [PMID: 32913678 PMCID: PMC7456531 DOI: 10.7717/peerj.9772] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Accepted: 07/30/2020] [Indexed: 01/22/2023] Open
Abstract
Subcellular relocalization of proteins determines an organism's metabolic repertoire and thereby its survival in unique evolutionary niches. In plants, the plastid and its various morphotypes import a large and varied number of nuclear-encoded proteins to orchestrate vital biochemical reactions in a spatiotemporal context. Recent comparative genomics analysis and high-throughput shotgun proteomics data indicate that there are a large number of plastid-targeted proteins that are either semi-conserved or non-conserved across different lineages. This implies that homologs are differentially targeted across different species, which is feasible only if proteins have gained or lost plastid targeting peptides during evolution. In this study, a broad, multi-genome analysis of 15 phylogenetically diverse genera and in-depth analyses of pangenomes from Arabidopsis and Brachypodium were performed to address the question of how proteins acquire or lose plastid targeting peptides. The analysis revealed that random insertions or deletions were the dominant mechanism by which novel transit peptides are gained by proteins. While gene duplication was not a strict requirement for the acquisition of novel subcellular targeting, 40% of novel plastid-targeted genes were found to be most closely related to a sequence within the same genome, and of these, 30.5% resulted from alternative transcription or translation initiation sites. Interestingly, analysis of the distribution of amino acids in the transit peptides of known and predicted chloroplast-targeted proteins revealed monocot and eudicot-specific preferences in residue distribution.
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Affiliation(s)
- Ryan W. Christian
- Molecular Plant Sciences, Washington State University, Pullman, WA, USA
| | - Seanna L. Hewitt
- Molecular Plant Sciences, Washington State University, Pullman, WA, USA
| | - Grant Nelson
- Molecular Plant Sciences, Washington State University, Pullman, WA, USA
| | - Eric H. Roalson
- Molecular Plant Sciences, Washington State University, Pullman, WA, USA
- School of Biological Sciences, Washington State University, Pullman, WA, USA
| | - Amit Dhingra
- Molecular Plant Sciences, Washington State University, Pullman, WA, USA
- Department of Horticulture, Washington State University, Pullman, WA, USA
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30
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Tang L, Yang G, Ma M, Liu X, Li B, Xie J, Fu Y, Chen T, Yu Y, Chen W, Jiang D, Cheng J. An effector of a necrotrophic fungal pathogen targets the calcium-sensing receptor in chloroplasts to inhibit host resistance. MOLECULAR PLANT PATHOLOGY 2020; 21:686-701. [PMID: 32105402 PMCID: PMC7170781 DOI: 10.1111/mpp.12922] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 01/14/2020] [Accepted: 01/20/2020] [Indexed: 05/03/2023]
Abstract
SsITL, a secretory protein of the necrotrophic phytopathogen Sclerotinia sclerotiorum, was previously reported to suppress host immunity at the early stages of infection. However, the molecular mechanism that SsITL uses to inhibit plant defence against S. sclerotiorum has not yet been elucidated. Here, we report that SsITL interacted with a chloroplast-localized calcium-sensing receptor, CAS, in chloroplasts. We found that CAS is a positive regulator of the salicylic acid signalling pathway in plant immunity to S. sclerotiorum and CAS-mediated resistance against S. sclerotiorum depends on Ca2+ signalling. Furthermore, we showed that SsITL could interfere with the plant salicylic acid (SA) signalling pathway and SsITL-expressing transgenic plants were more susceptible to S. sclerotiorum. However, truncated SsITLs (SsITL-NT1 or SsITL-CT1) that lost the ability to interact with CAS do not affect plant resistance to S. sclerotiorum. Taken together, our findings reveal that SsITL inhibits SA accumulation during the early stage of infection by interacting with CAS and then facilitating the infection by S. sclerotiorum.
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Affiliation(s)
- Liguang Tang
- State Key Laboratory of Agricultural MicrobiologyHuazhong Agricultural UniversityWuhan, Hubei ProvinceChina
- The Provincial Key Lab of Plant Pathology of Hubei ProvinceCollege of Plant Science and TechnologyHuazhong Agricultural UniversityWuhan, Hubei ProvinceChina
| | - Guogen Yang
- School of Plant ProtectionAnhui Agricultural UniversityHefeiChina
| | - Ming Ma
- State Key Laboratory of Agricultural MicrobiologyHuazhong Agricultural UniversityWuhan, Hubei ProvinceChina
- The Provincial Key Lab of Plant Pathology of Hubei ProvinceCollege of Plant Science and TechnologyHuazhong Agricultural UniversityWuhan, Hubei ProvinceChina
| | - Xiaofan Liu
- State Key Laboratory of Agricultural MicrobiologyHuazhong Agricultural UniversityWuhan, Hubei ProvinceChina
- The Provincial Key Lab of Plant Pathology of Hubei ProvinceCollege of Plant Science and TechnologyHuazhong Agricultural UniversityWuhan, Hubei ProvinceChina
| | - Bo Li
- State Key Laboratory of Agricultural MicrobiologyHuazhong Agricultural UniversityWuhan, Hubei ProvinceChina
- The Provincial Key Lab of Plant Pathology of Hubei ProvinceCollege of Plant Science and TechnologyHuazhong Agricultural UniversityWuhan, Hubei ProvinceChina
| | - Jiatao Xie
- State Key Laboratory of Agricultural MicrobiologyHuazhong Agricultural UniversityWuhan, Hubei ProvinceChina
- The Provincial Key Lab of Plant Pathology of Hubei ProvinceCollege of Plant Science and TechnologyHuazhong Agricultural UniversityWuhan, Hubei ProvinceChina
| | - Yanping Fu
- The Provincial Key Lab of Plant Pathology of Hubei ProvinceCollege of Plant Science and TechnologyHuazhong Agricultural UniversityWuhan, Hubei ProvinceChina
| | - Tao Chen
- The Provincial Key Lab of Plant Pathology of Hubei ProvinceCollege of Plant Science and TechnologyHuazhong Agricultural UniversityWuhan, Hubei ProvinceChina
| | - Yang Yu
- College of Plant ProtectionSouthwest UniversityChongqing CityChina
| | - Weidong Chen
- United States Department of AgricultureAgricultural Research ServiceWashington State UniversityPullmanWAUSA
| | - Daohong Jiang
- State Key Laboratory of Agricultural MicrobiologyHuazhong Agricultural UniversityWuhan, Hubei ProvinceChina
- The Provincial Key Lab of Plant Pathology of Hubei ProvinceCollege of Plant Science and TechnologyHuazhong Agricultural UniversityWuhan, Hubei ProvinceChina
| | - Jiasen Cheng
- State Key Laboratory of Agricultural MicrobiologyHuazhong Agricultural UniversityWuhan, Hubei ProvinceChina
- The Provincial Key Lab of Plant Pathology of Hubei ProvinceCollege of Plant Science and TechnologyHuazhong Agricultural UniversityWuhan, Hubei ProvinceChina
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31
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Collmer A. James Robert Alfano, A Giant in Phytopathogenic Bacteria Effector Biology. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2020; 33:377-381. [PMID: 31990622 DOI: 10.1094/mpmi-12-19-0354-cr] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The worldwide molecular plant-microbe interactions research community was significantly diminished in November 2019 by the death of James "Jim" Robert Alfano at age 56. Jim was a giant in our field, who gained key insights into plant pathogenesis using the model bacterial pathogen Pseudomonas syringae. As a mentor, collaborator, and, above all, a friend, I know Jim's many dimensions and accomplishments and, sadly, the depth of loss being felt by the many people around the world who were touched by him. In tracing the path of Jim's career, I will emphasize the historical context and impact of his advances and, finally, the essence of the person we will so miss.
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Affiliation(s)
- Alan Collmer
- School of Integrative Plant Science, Section of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY 14853, U.S.A
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Kretschmer M, Damoo D, Djamei A, Kronstad J. Chloroplasts and Plant Immunity: Where Are the Fungal Effectors? Pathogens 2019; 9:E19. [PMID: 31878153 PMCID: PMC7168614 DOI: 10.3390/pathogens9010019] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 12/17/2019] [Accepted: 12/21/2019] [Indexed: 12/12/2022] Open
Abstract
Chloroplasts play a central role in plant immunity through the synthesis of secondary metabolites and defense compounds, as well as phytohormones, such as jasmonic acid and salicylic acid. Additionally, chloroplast metabolism results in the production of reactive oxygen species and nitric oxide as defense molecules. The impact of viral and bacterial infections on plastids and chloroplasts has been well documented. In particular, bacterial pathogens are known to introduce effectors specifically into chloroplasts, and many viral proteins interact with chloroplast proteins to influence viral replication and movement, and plant defense. By contrast, clear examples are just now emerging for chloroplast-targeted effectors from fungal and oomycete pathogens. In this review, we first present a brief overview of chloroplast contributions to plant defense and then discuss examples of connections between fungal interactions with plants and chloroplast function. We then briefly consider well-characterized bacterial effectors that target chloroplasts as a prelude to discussing the evidence for fungal effectors that impact chloroplast activities.
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Affiliation(s)
- Matthias Kretschmer
- Michael Smith Laboratories, Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; (M.K.); (D.D.)
| | - Djihane Damoo
- Michael Smith Laboratories, Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; (M.K.); (D.D.)
| | - Armin Djamei
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) OT Gatersleben Corrensstrasse 3, D-06466 Stadt Seeland, Germany;
| | - James Kronstad
- Michael Smith Laboratories, Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; (M.K.); (D.D.)
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Xu Q, Tang C, Wang X, Sun S, Zhao J, Kang Z, Wang X. An effector protein of the wheat stripe rust fungus targets chloroplasts and suppresses chloroplast function. Nat Commun 2019; 10:5571. [PMID: 31804478 PMCID: PMC6895047 DOI: 10.1038/s41467-019-13487-6] [Citation(s) in RCA: 115] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2019] [Accepted: 11/05/2019] [Indexed: 01/02/2023] Open
Abstract
Chloroplasts are important for photosynthesis and for plant immunity against microbial pathogens. Here we identify a haustorium-specific protein (Pst_12806) from the wheat stripe rust fungus, Puccinia striiformis f. sp. tritici (Pst), that is translocated into chloroplasts and affects chloroplast function. Transient expression of Pst_12806 inhibits BAX-induced cell death in tobacco plants and reduces Pseudomonas-induced hypersensitive response in wheat. It suppresses plant basal immunity by reducing callose deposition and the expression of defense-related genes. Pst_12806 is upregulated during infection, and its knockdown (by host-induced gene silencing) reduces Pst growth and development, likely due to increased ROS accumulation. Pst_12806 interacts with the C-terminal Rieske domain of the wheat TaISP protein (a putative component of the cytochrome b6-f complex). Expression of Pst_12806 in plants reduces electron transport rate, photosynthesis, and production of chloroplast-derived ROS. Silencing TaISP by virus-induced gene silencing in a susceptible wheat cultivar reduces fungal growth and uredinium development, suggesting an increase in resistance against Pst infection.
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Affiliation(s)
- Qiang Xu
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Chunlei Tang
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Xiaodong Wang
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Shutian Sun
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Jinren Zhao
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Zhensheng Kang
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, 712100, Shaanxi, China.
| | - Xiaojie Wang
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, 712100, Shaanxi, China.
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Ding X, Jimenez‐Gongora T, Krenz B, Lozano‐Duran R. Chloroplast clustering around the nucleus is a general response to pathogen perception in Nicotiana benthamiana. MOLECULAR PLANT PATHOLOGY 2019; 20:1298-1306. [PMID: 31257720 PMCID: PMC6715600 DOI: 10.1111/mpp.12840] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
It is increasingly clear that chloroplasts play a central role in plant stress responses. Upon activation of immune responses, chloroplasts are the source of multiple defensive signals, including reactive oxygen species (ROS). Intriguingly, it has been described that chloroplasts establish physical contact with the nucleus, through clustering around it and extending stromules, following activation of effector-triggered immunity (ETI). However, how prevalent this phenomenon is in plant-pathogen interactions, how its induction occurs, and what the underlying biological significance is are important questions that remain unanswered. Here, we describe that the chloroplast perinuclear clustering seems to be a general plant response upon perception of an invasion threat. Indeed, activation of pattern-triggered immunity, ETI, transient expression of the Rep protein from geminiviruses, or infection with viruses or bacteria all are capable of triggering this response in Nicotiana benthamiana. Interestingly, this response seems non-cell-autonomous, and exogenous treatment with H2 O2 is sufficient to elicit this relocalization of chloroplasts, which appears to require accumulation of ROS. Taken together, our results indicate that chloroplasts cluster around the nucleus during plant-pathogen interactions, suggesting a fundamental role of this positioning in plant defence, and identify ROS as sufficient and possibly required for the onset of this response.
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Affiliation(s)
- Xue Ding
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant SciencesChinese Academy of SciencesShanghai201602China
- University of the Chinese Academy of SciencesBeijing100049China
| | - Tamara Jimenez‐Gongora
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant SciencesChinese Academy of SciencesShanghai201602China
- University of the Chinese Academy of SciencesBeijing100049China
| | - Bjӧrn Krenz
- Leibniz Institute DSMZ38124BraunschweigGermany
| | - Rosa Lozano‐Duran
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant SciencesChinese Academy of SciencesShanghai201602China
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Genome analysis of Pseudomonas syringae pv. actinidiae biovar 6, which produces the phytotoxins, phaseolotoxin and coronatine. Sci Rep 2019; 9:3836. [PMID: 30846809 PMCID: PMC6405952 DOI: 10.1038/s41598-019-40754-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Accepted: 02/21/2019] [Indexed: 12/12/2022] Open
Abstract
The kiwifruit bacterial canker pathogen, Pseudomonas syringae pv. actinidiae (Psa), causes enormous economic damages in many kiwifruit producing countries. In 2015, biovar 6, the novel biovar of Psa, was found in Nagano Prefecture, Japan. The genomes of two representative strains of biovar 6 (MAFF 212134 and MAFF 212141) were sequenced and analysed, indicating that their genomes are the most similar to that of biovar 3 among the known Psa biovars, based on average nucleotide identity analysis. Biovar 3 has neither the phaseolotoxin synthesis gene cluster nor the coronatine synthesis gene cluster, whereas biovar 6 has both clusters and produces both phytotoxins. We found that biovar 6 possesses 29 type III secreted effector (T3SE) genes, among which avrRps4 and hopBI1 are unique to biovar 6. The expression of T3SE genes and two phytotoxin synthesis gene clusters of biovar 6 during the early stages of host infection was investigated using RNA-Seq analysis, showing that these genes could be grouped into three categories: constantly expressed genes, constantly suppressed genes, and temporarily induced genes. A PCR assay was established to differentiate biovar 6 strains from the other Psa biovars and the closely related pathovar, pv. actinidifoliorum, by using avrRps4 as a biovar 6-specific marker gene.
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Lu Y, Yao J. Chloroplasts at the Crossroad of Photosynthesis, Pathogen Infection and Plant Defense. Int J Mol Sci 2018; 19:E3900. [PMID: 30563149 PMCID: PMC6321325 DOI: 10.3390/ijms19123900] [Citation(s) in RCA: 103] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 11/30/2018] [Accepted: 12/03/2018] [Indexed: 12/31/2022] Open
Abstract
Photosynthesis, pathogen infection, and plant defense are three important biological processes that have been investigated separately for decades. Photosynthesis generates ATP, NADPH, and carbohydrates. These resources are utilized for the synthesis of many important compounds, such as primary metabolites, defense-related hormones abscisic acid, ethylene, jasmonic acid, and salicylic acid, and antimicrobial compounds. In plants and algae, photosynthesis and key steps in the synthesis of defense-related hormones occur in chloroplasts. In addition, chloroplasts are major generators of reactive oxygen species and nitric oxide, and a site for calcium signaling. These signaling molecules are essential to plant defense as well. All plants grown naturally are attacked by pathogens. Bacterial pathogens enter host tissues through natural openings or wounds. Upon invasion, bacterial pathogens utilize a combination of different virulence factors to suppress host defense and promote pathogenicity. On the other hand, plants have developed elaborate defense mechanisms to protect themselves from pathogen infections. This review summarizes recent discoveries on defensive roles of signaling molecules made by plants (primarily in their chloroplasts), counteracting roles of chloroplast-targeted effectors and phytotoxins elicited by bacterial pathogens, and how all these molecules crosstalk and regulate photosynthesis, pathogen infection, and plant defense, using chloroplasts as a major battlefield.
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Affiliation(s)
- Yan Lu
- Department of Biological Sciences, Western Michigan University, Kalamazoo, MI 49008, USA.
| | - Jian Yao
- Department of Biological Sciences, Western Michigan University, Kalamazoo, MI 49008, USA.
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Nakano M, Mukaihara T. Ralstonia solanacearum Type III Effector RipAL Targets Chloroplasts and Induces Jasmonic Acid Production to Suppress Salicylic Acid-Mediated Defense Responses in Plants. PLANT & CELL PHYSIOLOGY 2018; 59:2576-2589. [PMID: 30165674 DOI: 10.1093/pcp/pcy177] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 08/23/2018] [Indexed: 05/06/2023]
Abstract
Ralstonia solanacearum is the causal agent of bacterial wilt disease of plants. This pathogen injects more than 70 type III effector proteins called Rips (Ralstonia-injected proteins) into plant cells to succeed in infection. One of the Rips, RipAL, contains a putative lipase domain that shared homology with Arabidopsis DEFECTIVE IN ANTHER DEHISCENCE1 (DAD1). RipAL significantly suppressed pattern-triggered immunity in leaves of Nicotiana benthamiana. Subcellular localization analyses suggest that RipAL localizes to chloroplasts and targets chloroplast lipids in plant cells. Notably, the expression of RipAL markedly increased the jasmonic acid (JA) and JA-isoleucine levels, and induced the expressions of JA-signaling marker genes in plant leaves. Simultaneously, RipAL greatly reduced the salicylic acid (SA) level and decreased the expression levels of SA-signaling marker genes. Mutations in two putative catalytic residues in the DAD1-like lipase domain abolished the ability of RipAL to induce JA production and suppress SA signaling. Infection of R. solanacearum also induced JA production and simultaneously decreased the SA level in susceptible pepper leaves in a ripAL-dependent manner. The growth of R. solanacearum enhanced in plants with silenced CaICS1, which encodes the SA synthesis enzyme isochorismate synthase 1. These results indicate that SA signaling is involved in the defense response against R. solanacearum and that R. solanacearum uses RipAL to induce JA production and suppress SA signaling in plant cells.
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Affiliation(s)
- Masahito Nakano
- Research Institute for Biological Sciences, Okayama (RIBS), 7549-1 Yoshikawa, Kibichuo-cho, Okayama, Japan
| | - Takafumi Mukaihara
- Research Institute for Biological Sciences, Okayama (RIBS), 7549-1 Yoshikawa, Kibichuo-cho, Okayama, Japan
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38
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Akimoto‐Tomiyama C, Tanabe S, Kajiwara H, Minami E, Ochiai H. Loss of chloroplast-localized protein phosphatase 2Cs in Arabidopsis thaliana leads to enhancement of plant immunity and resistance to Xanthomonas campestris pv. campestris infection. MOLECULAR PLANT PATHOLOGY 2018; 19:1184-1195. [PMID: 28815858 PMCID: PMC6637992 DOI: 10.1111/mpp.12596] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Revised: 08/08/2017] [Accepted: 08/12/2017] [Indexed: 05/20/2023]
Abstract
Protein phosphatases (PPs) counteract kinases in reversible phosphorylation events during numerous signal transduction pathways in eukaryotes. PP2Cs, one of the four major classes of the serine/threonine-specific PP family, are greatly expanded in plants. Thus, PP2Cs are thought to play a specific role in signal transduction pathways. Some rice PP2Cs classified in subgroup K are responsive to infection by the compatible Xanthomonas oryzae pv. oryzae, the causal agent of bacterial blight. In Arabidopsis thaliana, orthologous PP2C genes (AtPP2C62 and AtPP2C26) classified to subgroup K are also responsive to Xanthomonas campestris pv. campestris (Xcc, causal agent of black rot) infection. To elucidate the function of these subgroup K PP2Cs, atpp2c62- and atpp2c26-deficient A. thaliana mutants were characterized. A double mutant plant which was inoculated with a compatible Xcc showed reduced lesion development, as well as the suppression of bacterial multiplication. AtPP2C62 and AtPP2C26 localized to the chloroplast. Furthermore, the photosynthesis-related protein, chaperonin-60, was indicated as the potential candidate for the dephosphorylated substrate catalysed by AtPP2C62 and AtPP2C26 using two-dimensional isoelectric focusing sodium dodecylsulfate-polyacrylamide gel electrophoresis (2D-IDF-SDS-PAGE). Taken together, AtPP2C62 and AtPP2C26 are suggested to be involved in both photosynthesis and suppression of the plant immune system. These results imply the occurrence of crosstalk between photosynthesis and the plant defence system to control productivity under pathogen infection.
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Affiliation(s)
- Chiharu Akimoto‐Tomiyama
- Institute of Agrobiological Sciences, National Agriculture and Food Research OrganizationTsukubaIbaraki 305‐8602, Japan
| | - Shigeru Tanabe
- Institute of Agrobiological Sciences, National Agriculture and Food Research OrganizationTsukubaIbaraki 305‐8602, Japan
- Present address:
Sakata Seed CorporationYokohamaJapan
| | - Hideyuki Kajiwara
- Advanced Analysis CenterNational Agriculture and Food Research OrganizationTsukubaIbaraki 305‐8602, Japan
| | - Eiichi Minami
- Institute of Agrobiological Sciences, National Agriculture and Food Research OrganizationTsukubaIbaraki 305‐8602, Japan
| | - Hirokazu Ochiai
- Institute of Agrobiological Sciences, National Agriculture and Food Research OrganizationTsukubaIbaraki 305‐8602, Japan
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Liu Y, Lan X, Song S, Yin L, Dry IB, Qu J, Xiang J, Lu J. In Planta Functional Analysis and Subcellular Localization of the Oomycete Pathogen Plasmopara viticola Candidate RXLR Effector Repertoire. FRONTIERS IN PLANT SCIENCE 2018; 9:286. [PMID: 29706971 PMCID: PMC5908963 DOI: 10.3389/fpls.2018.00286] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Accepted: 02/19/2018] [Indexed: 05/20/2023]
Abstract
Downy mildew is one of the most destructive diseases of grapevine, causing tremendous economic loss in the grape and wine industry. The disease agent Plasmopara viticola is an obligate biotrophic oomycete, from which over 100 candidate RXLR effectors have been identified. In this study, 83 candidate RXLR effector genes (PvRXLRs) were cloned from the P. viticola isolate "JL-7-2" genome. The results of the yeast signal sequence trap assay indicated that most of the candidate effectors are secretory proteins. The biological activities and subcellular localizations of all the 83 effectors were analyzed via a heterologous Agrobacterium-mediated Nicotiana benthamiana expression system. Results showed that 52 effectors could completely suppress cell death triggered by elicitin, 10 effectors could partially suppress cell death, 11 effectors were unable to suppress cell death, and 10 effectors themselves triggered cell death. Live-cell imaging showed that the majority of the effectors (76 of 83) could be observed with informative fluorescence signals in plant cells, among which 34 effectors were found to be targeted to both the nucleus and cytosol, 29 effectors were specifically localized in the nucleus, and 9 effectors were targeted to plant membrane system. Interestingly, three effectors PvRXLR61, 86 and 161 were targeted to chloroplasts, and one effector PvRXLR54 was dually targeted to chloroplasts and mitochondria. However, western blot analysis suggested that only PvRXLR86 carried a cleavable N-terminal transit peptide and underwent processing in planta. Many effectors have previously been predicted to target organelles, however, to the best of our knowledge, this is the first study to provide experimental evidence of oomycete effectors targeted to chloroplasts and mitochondria.
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Affiliation(s)
- Yunxiao Liu
- College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
- Center for Viticulture and Enology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Xia Lan
- College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
- Center for Viticulture and Enology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Shiren Song
- Center for Viticulture and Enology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Ling Yin
- Guangxi Crop Genetic Improvement and Biotechnology Laboratory, Guangxi Academy of Agricultural Sciences, Nanning, China
| | - Ian B. Dry
- CSIRO Agriculture & Food, Urrbrae, SA, Australia
| | - Junjie Qu
- Guangxi Crop Genetic Improvement and Biotechnology Laboratory, Guangxi Academy of Agricultural Sciences, Nanning, China
| | - Jiang Xiang
- Center for Viticulture and Enology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Jiang Lu
- Center for Viticulture and Enology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
- Guangxi Crop Genetic Improvement and Biotechnology Laboratory, Guangxi Academy of Agricultural Sciences, Nanning, China
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40
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The role of chloroplasts in plant pathology. Essays Biochem 2018; 62:21-39. [PMID: 29273582 DOI: 10.1042/ebc20170020] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 11/22/2017] [Accepted: 11/28/2017] [Indexed: 12/13/2022]
Abstract
Plants have evolved complex tolerance systems to survive abiotic and biotic stresses. Central to these programmes is a sophisticated conversation of signals between the chloroplast and the nucleus. In this review, we examine the antagonism between abiotic stress tolerance (AST) and immunity: we propose that to generate immunogenic signals, plants must disable AST systems, in particular those that manage reactive oxygen species (ROS), while the pathogen seeks to reactivate or enhance those systems to achieve virulence. By boosting host systems of AST, pathogens trick the plant into suppressing chloroplast immunogenic signals and steer the host into making an inappropriate immune response. Pathogens disrupt chloroplast function, both transcriptionally-by secreting effectors that alter host gene expression by interacting with defence-related kinase cascades, with transcription factors, or with promoters themselves-and post-transcriptionally, by delivering effectors that enter the chloroplast or alter the localization of host proteins to change chloroplast activities. These mechanisms reconfigure the chloroplast proteome and chloroplast-originating immunogenic signals in order to promote infection.
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The bacterial type III-secreted protein AvrRps4 is a bipartite effector. PLoS Pathog 2018; 14:e1006984. [PMID: 29601603 PMCID: PMC5895054 DOI: 10.1371/journal.ppat.1006984] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Revised: 04/11/2018] [Accepted: 03/20/2018] [Indexed: 11/21/2022] Open
Abstract
Bacterial effector proteins secreted into host plant cells manipulate those cells to the benefit of the pathogen, but effector-triggered immunity (ETI) occurs when effectors are recognized by host resistance proteins. The RPS4/RRS1 pair recognizes the Pseudomonas syringae pv. pisi effector AvrRps4. AvrRps4 is processed in planta into AvrRps4N (133 amino acids), homologous to the N-termini of other effectors including the native P. syringae pv. tomato strain DC3000 effector HopK1, and AvrRps4C (88 amino acids). Previous data suggested that AvrRps4C alone is necessary and sufficient for resistance when overexpressed in heterologous systems. We show that delivering AvrRps4C from DC3000, but not from a DC3000 hopK1- strain, triggers resistance in the Arabidopsis accession Col-0. Delivering AvrRps4C in tandem with AvrRps4N, or as a chimera with HopK1N, fully complements AvrRps4-triggered immunity. AvrRps4N in the absence of AvrRps4C enhances virulence in Col-0. In addition, AvrRps4N triggers a hypersensitive response in lettuce that is attenuated by coexpression of AvrRps4C, further supporting the role of AvrRps4N as a bona fide effector domain. Based on these results we propose that evolutionarily, fusion of AvrRps4C to AvrRps4N may have counteracted recognition of AvrRps4N, and that the plant RPS4/RRS1 resistance gene pair was selected as a countermeasure. We conclude that AvrRps4 represents an unusual chimeric effector, with recognition in Arabidopsis by RPS4/RRS1 requiring the presence of both processed effector moieties. An important component of the plant immune system relies on the detection of pathogen-derived effectors by immune receptors called resistance proteins. Bacterial pathogens inject effectors into the host cell via a dedicated secretion system to suppress defenses and to manipulate the physiology of the host cell to the pathogen's advantage. Usually, a single resistance protein recognizes a single effector, but an increasing number of exceptions and elaborations on this one-to-one relationship are known. The plant Arabidopsis uses a pair of resistance proteins, RRS1 and RPS4, to detect the effector AvrRps4. After injection into the cell, AvrRps4 is cleaved into two protein parts, and it had been assumed that only the C-terminal part needs to be present to trigger RPS4/RRS1. We show here that both AvrRps4 parts are required for triggering resistance in Arabidopsis, and that the N-terminal part, which previously had been assumed to only function in effector secretion into the host cell, in fact on its own has some functions of an effector. This conclusion is supported by the observation that the N-terminal part of AvrRps4 is sufficient to trigger resistance in lettuce. The fusion of the two AvrRps4 parts may have arisen to counteract plant defenses.
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42
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Abstract
Pseudomonas syringae is one of the best-studied plant pathogens and serves as a model for understanding host-microorganism interactions, bacterial virulence mechanisms and host adaptation of pathogens as well as microbial evolution, ecology and epidemiology. Comparative genomic studies have identified key genomic features that contribute to P. syringae virulence. P. syringae has evolved two main virulence strategies: suppression of host immunity and creation of an aqueous apoplast to form its niche in the phyllosphere. In addition, external environmental conditions such as humidity profoundly influence infection. P. syringae may serve as an excellent model to understand virulence and also of how pathogenic microorganisms integrate environmental conditions and plant microbiota to become ecologically robust and diverse pathogens of the plant kingdom.
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Park E, Nedo A, Caplan JL, Dinesh-Kumar SP. Plant-microbe interactions: organelles and the cytoskeleton in action. THE NEW PHYTOLOGIST 2018; 217:1012-1028. [PMID: 29250789 DOI: 10.1111/nph.14959] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Accepted: 11/10/2017] [Indexed: 05/06/2023]
Abstract
Contents Summary 1012 I. Introduction 1012 II. The endomembrane system in plant-microbe interactions 1013 III. The cytoskeleton in plant-microbe interactions 1017 IV. Organelles in plant-microbe interactions 1019 V. Inter-organellar communication in plant-microbe interactions 1022 VI. Conclusions and prospects 1023 Acknowledgements 1024 References 1024 SUMMARY: Plants have evolved a multilayered immune system with well-orchestrated defense strategies against pathogen attack. Multiple immune signaling pathways, coordinated by several subcellular compartments and interactions between these compartments, play important roles in a successful immune response. Pathogens use various strategies to either directly attack the plant's immune system or to indirectly manipulate the physiological status of the plant to inhibit an immune response. Microscopy-based approaches have allowed the direct visualization of membrane trafficking events, cytoskeleton reorganization, subcellular dynamics and inter-organellar communication during the immune response. Here, we discuss the contributions of organelles and the cytoskeleton to the plant's defense response against microbial pathogens, as well as the mechanisms used by pathogens to target these compartments to overcome the plant's defense barrier.
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Affiliation(s)
- Eunsook Park
- Department of Plant Biology and The Genome Center, College of Biological Sciences, University of California, Davis, CA, 95616, USA
| | - Alexander Nedo
- Department of Biological Sciences, Delaware Biotechnology Institute, University of Delaware, Newark, DE, 19711, USA
| | - Jeffrey L Caplan
- Department of Biological Sciences, Delaware Biotechnology Institute, University of Delaware, Newark, DE, 19711, USA
- Department of Plant and Soil Sciences, University of Delaware, Newark, DE, 19711, USA
| | - Savithramma P Dinesh-Kumar
- Department of Plant Biology and The Genome Center, College of Biological Sciences, University of California, Davis, CA, 95616, USA
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44
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Su J, Spears BJ, Kim SH, Gassmann W. Constant vigilance: plant functions guarded by resistance proteins. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2018; 93:637-650. [PMID: 29232015 DOI: 10.1111/tpj.13798] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 11/27/2017] [Accepted: 11/30/2017] [Indexed: 05/09/2023]
Abstract
Unlike animals, plants do not have an adaptive immune system and have instead evolved sophisticated and multi-layered innate immune mechanisms. To overcome plant immunity, pathogens secrete a diverse array of effectors into the apoplast and virtually all cellular compartments to dampen immune signaling and interfere with plant functions. Here we describe the scope of the arms race throughout the cell and summarize various strategies used by both plants and pathogens. Through studying the ongoing evolutionary battle between plants and key pathogens, we may yet uncover potential ways to achieve the ultimate goal of engineering broad-spectrum resistant crops without affecting food quality or productivity.
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Affiliation(s)
- Jianbin Su
- Division of Plant Sciences, C.S. Bond Life Sciences Center and Interdisciplinary Plant Group, University of Missouri, Columbia, MO, 65211, USA
| | - Benjamin J Spears
- Division of Plant Sciences, C.S. Bond Life Sciences Center and Interdisciplinary Plant Group, University of Missouri, Columbia, MO, 65211, USA
| | - Sang Hee Kim
- Division of Applied Life Science (BK 21 Plus Program), Plant Molecular Biology and Biotechnology Research Center, Division of Life Science, Gyeongsang National University, Jinju, 52828, Korea
| | - Walter Gassmann
- Division of Plant Sciences, C.S. Bond Life Sciences Center and Interdisciplinary Plant Group, University of Missouri, Columbia, MO, 65211, USA
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45
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Varden FA, De la Concepcion JC, Maidment JH, Banfield MJ. Taking the stage: effectors in the spotlight. CURRENT OPINION IN PLANT BIOLOGY 2017; 38:25-33. [PMID: 28460241 DOI: 10.1016/j.pbi.2017.04.013] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2017] [Revised: 04/10/2017] [Accepted: 04/11/2017] [Indexed: 06/07/2023]
Abstract
Plant pathogens are a serious threat to agriculture and to global food security, causing diverse crop diseases which lead to extensive annual yield losses. Production of effector proteins by pathogens, to manipulate host cellular processes, is central to their success. An understanding of fundamental effector biology is key to addressing the threat posed by these pathogens. Recent advances in 'omics' technologies have facilitated high-throughput identification of putative effector proteins, while evolving cellular, structural and biochemical approaches have assisted in characterising their function. Furthermore, structures of effectors in complex with host factors now provide opportunities for applying our knowledge of effector biology to influence disease outcomes. In this review, we highlight recent advances in the field and suggest avenues for future research.
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Affiliation(s)
- Freya A Varden
- Dept. of Biological Chemistry, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, United Kingdom
| | | | - Josephine Hr Maidment
- Dept. of Biological Chemistry, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, United Kingdom
| | - Mark J Banfield
- Dept. of Biological Chemistry, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, United Kingdom.
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Castañeda‐Ojeda MP, López‐Solanilla E, Ramos C. Differential modulation of plant immune responses by diverse members of the Pseudomonas savastanoi pv. savastanoi HopAF type III effector family. MOLECULAR PLANT PATHOLOGY 2017; 18:625-634. [PMID: 27116193 PMCID: PMC6638205 DOI: 10.1111/mpp.12420] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Revised: 04/21/2016] [Accepted: 04/22/2016] [Indexed: 05/25/2023]
Abstract
The Pseudomonas savastanoi pv. savastanoi NCPPB 3335 type III secretion system (T3SS) effector repertoire includes 33 candidates, seven of which translocate into host cells and interfere with plant defences. The present study was performed to investigate the co-existence of both plasmid- and chromosomal-encoded members of the HopAF effector family, HopAF1-1 and HopAF1-2, respectively, in the genome of NCPPB 3335. Here, we show that the HopAF1 paralogues are widely distributed in the Pseudomonas syringae complex, where HopAF1-1 is most similar to the homologues encoded by other P. syringae pathovars infecting woody hosts that belong to phylogroups 1 and 3. We show that the expression of both HopAF1-1 and HopAF-2 is transcriptionally dependent on HrpL and demonstrate their delivery into Nicotiana tabacum leaves. Although the heterologous delivery of either HopAF1-1 or HopAF1-2 significantly suppressed the production of defence-associated reactive oxygen species levels, only HopAF1-2 reduced the levels of callose deposition. Moreover, the expression of HopAF1-2 by functionally effectorless P. syringae pv. tomato DC3000D28E completely inhibited the hypersensitive response in tobacco and significantly increased the competitiveness of the strain in Nicotiana benthamiana. Despite their functional differences, subcellular localization studies reveal that green fluorescent protein (GFP) fusions to either HopAF1-1 or HopAF1-2 are targeted to the plasma membrane when they are expressed in plant cells, a process that is completely dependent on the integrity of their N-myristoylation motif. Our results further support the notion that highly similar T3SS effectors might differentially interact with diverse plant targets, even when they co-localize in the same cell compartment.
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Affiliation(s)
- M. Pilar Castañeda‐Ojeda
- Área de Genética, Facultad de Ciencias, Instituto de Hortofruticultura Subtropical y Mediterránea ‘La Mayora’, Universidad de Málaga‐Consejo Superior de Investigaciones Científicas (IHSM‐UMA‐CSIC)Campus Teatinos s/nMálagaE‐29010Spain
| | - Emilia López‐Solanilla
- Centro de Biotecnología y Genómica de Plantas (CBGP), Universidad Politécnica de Madrid‐Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Parque Científico y Tecnológico de la UPM, Campus de MontegancedoPozuelo de AlarcónMadrid28223Spain
- Departamento de BiotecnologíaEscuela Técnica Superior de Ingenieros Agrónomos, UPMAvda. Complutense S/NMadrid28040Spain
| | - Cayo Ramos
- Área de Genética, Facultad de Ciencias, Instituto de Hortofruticultura Subtropical y Mediterránea ‘La Mayora’, Universidad de Málaga‐Consejo Superior de Investigaciones Científicas (IHSM‐UMA‐CSIC)Campus Teatinos s/nMálagaE‐29010Spain
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Choi S, Jayaraman J, Segonzac C, Park HJ, Park H, Han SW, Sohn KH. Pseudomonas syringae pv. actinidiae Type III Effectors Localized at Multiple Cellular Compartments Activate or Suppress Innate Immune Responses in Nicotiana benthamiana. FRONTIERS IN PLANT SCIENCE 2017; 8:2157. [PMID: 29326748 PMCID: PMC5742410 DOI: 10.3389/fpls.2017.02157] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Accepted: 12/06/2017] [Indexed: 05/15/2023]
Abstract
Bacterial phytopathogen type III secreted (T3S) effectors have been strongly implicated in altering the interaction of pathogens with host plants. Therefore, it is useful to characterize the whole effector repertoire of a pathogen to understand the interplay of effectors in plants. Pseudomonas syringae pv. actinidiae is a causal agent of kiwifruit canker disease. In this study, we generated an Agrobacterium-mediated transient expression library of YFP-tagged T3S effectors from two strains of Psa, Psa-NZ V13 and Psa-NZ LV5, in order to gain insight into their mode of action in Nicotiana tabacum and N. benthamiana. Determining the subcellular localization of effectors gives an indication of the possible host targets of effectors. A confocal microscopy assay detecting YFP-tagged Psa effectors revealed that the nucleus, cytoplasm and cell periphery are major targets of Psa effectors. Agrobacterium-mediated transient expression of multiple Psa effectors induced HR-like cell death (HCD) in Nicotiana spp., suggesting that multiple Psa effectors may be recognized by Nicotiana spp.. Virus-induced gene silencing (VIGS) of several known plant immune regulators, EDS1, NDR1, or SGT1 specified the requirement of SGT1 in HCD induced by several Psa effectors in N. benthamiana. In addition, the suppression activity of Psa effectors on HCD-inducing proteins and PTI was assessed. Psa effectors showed differential suppression activities on each HCD inducer or PTI. Taken together, our Psa effector repertoire analysis highlights the great diversity of T3S effector functions in planta.
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Affiliation(s)
- Sera Choi
- Bioprotection Research Centre, Institute of Agriculture and Environment, Massey University, Palmerston North, New Zealand
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, South Korea
| | - Jay Jayaraman
- Bioprotection Research Centre, Institute of Agriculture and Environment, Massey University, Palmerston North, New Zealand
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, South Korea
| | - Cécile Segonzac
- Plant Science Department, Plant Genomics and Breeding Institute and Research Institute of Agriculture and Life Sciences, College of Agriculture and Life Sciences, Seoul National University, Seoul, South Korea
| | - Hye-Jee Park
- Department of Integrative Plant Science, Chung-Ang University, Anseong, South Korea
| | - Hanbi Park
- Department of Integrative Plant Science, Chung-Ang University, Anseong, South Korea
| | - Sang-Wook Han
- Department of Integrative Plant Science, Chung-Ang University, Anseong, South Korea
| | - Kee Hoon Sohn
- Bioprotection Research Centre, Institute of Agriculture and Environment, Massey University, Palmerston North, New Zealand
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, South Korea
- School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology, Pohang, South Korea
- *Correspondence: Kee Hoon Sohn,
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Aung K, Xin X, Mecey C, He SY. Subcellular Localization of Pseudomonas syringae pv. tomato Effector Proteins in Plants. Methods Mol Biol 2017; 1531:141-153. [PMID: 27837488 PMCID: PMC5643156 DOI: 10.1007/978-1-4939-6649-3_12] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/14/2023]
Abstract
Animal and plant pathogenic bacteria use type III secretion systems to translocate proteinaceous effectors to subvert innate immunity of their host organisms. Type III secretion/effector systems are a crucial pathogenicity factor in many bacterial pathogens of plants and animals. Pseudomonas syringae pv. tomato (Pst) DC3000 injects a total of 36 protein effectors that target a variety of host proteins. Studies of a subset of Pst DC3000 effectors demonstrated that bacterial effectors, once inside the host cell, are localized to different subcellular compartments, including plasma membrane, cytoplasm, mitochondria, chloroplast, and Trans-Golgi network, to carry out their virulence functions. Identifying the subcellular localization of bacterial effector proteins in host cells could provide substantial clues to understanding the molecular and cellular basis of the virulence activities of effector proteins. In this chapter, we present methods for transient or stable expression of bacterial effector proteins in tobacco and/or Arabidopsis thaliana for live cell imaging as well as confirming the subcellular localization in plants using fluorescent organelle markers or chemical treatment.
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Affiliation(s)
- Kyaw Aung
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI, 48824, USA
- Howard Hughes Medical Institute, Michigan State University, East Lansing, MI, 48824, USA
| | - Xiufang Xin
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI, 48824, USA
| | - Christy Mecey
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI, 48824, USA
| | - Sheng Yang He
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI, 48824, USA.
- Department of Plant Biology, Michigan State University, East Lansing, MI, 48824, USA.
- Howard Hughes Medical Institute, Michigan State University, East Lansing, MI, 48824, USA.
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Pfeilmeier S, Caly DL, Malone JG. Bacterial pathogenesis of plants: future challenges from a microbial perspective: Challenges in Bacterial Molecular Plant Pathology. MOLECULAR PLANT PATHOLOGY 2016; 17:1298-313. [PMID: 27170435 PMCID: PMC6638335 DOI: 10.1111/mpp.12427] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Revised: 05/08/2016] [Accepted: 05/10/2016] [Indexed: 05/03/2023]
Abstract
Plant infection is a complicated process. On encountering a plant, pathogenic microorganisms must first adapt to life on the epiphytic surface, and survive long enough to initiate an infection. Responsiveness to the environment is critical throughout infection, with intracellular and community-level signal transduction pathways integrating environmental signals and triggering appropriate responses in the bacterial population. Ultimately, phytopathogens must migrate from the epiphytic surface into the plant tissue using motility and chemotaxis pathways. This migration is coupled with overcoming the physical and chemical barriers to entry into the plant apoplast. Once inside the plant, bacteria use an array of secretion systems to release phytotoxins and protein effectors that fulfil diverse pathogenic functions (Fig. ) (Melotto and Kunkel, ; Phan Tran et al., ). As our understanding of the pathways and mechanisms underpinning plant pathogenicity increases, a number of central research challenges are emerging that will profoundly shape the direction of research in the future. We need to understand the bacterial phenotypes that promote epiphytic survival and surface adaptation in pathogenic bacteria. How do these pathways function in the context of the plant-associated microbiome, and what impact does this complex microbial community have on the onset and severity of plant infections? The huge importance of bacterial signal transduction to every stage of plant infection is becoming increasingly clear. However, there is a great deal to learn about how these signalling pathways function in phytopathogenic bacteria, and the contribution they make to various aspects of plant pathogenicity. We are increasingly able to explore the structural and functional diversity of small-molecule natural products from plant pathogens. We need to acquire a much better understanding of the production, deployment, functional redundancy and physiological roles of these molecules. Type III secretion systems (T3SSs) are important and well-studied contributors to bacterial disease. Several key unanswered questions will shape future investigations of these systems. We need to define the mechanism of hierarchical and temporal control of effector secretion. For successful infection, effectors need to interact with host components to exert their function. Advanced biochemical, proteomic and cell biological techniques will enable us to study the function of effectors inside the host cell in more detail and on a broader scale. Population genomics analyses provide insight into evolutionary adaptation processes of phytopathogens. The determination of the diversity and distribution of type III effectors (T3Es) and other virulence genes within and across pathogenic species, pathovars and strains will allow us to understand how pathogens adapt to specific hosts, the evolutionary pathways available to them, and the possible future directions of the evolutionary arms race between effectors and molecular plant targets. Although pathogenic bacteria employ a host of different virulence and proliferation strategies, as a result of the space constraints, this review focuses mainly on the hemibiotrophic pathogens. We discuss the process of plant infection from the perspective of these important phytopathogens, and highlight new approaches to address the outstanding challenges in this important and fast-moving field.
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Affiliation(s)
- Sebastian Pfeilmeier
- The Sainsbury Laboratory, Norwich Research Park, Norwich, NR4 7UH, UK
- John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Delphine L Caly
- Université de Lille, EA 7394, ICV - Institut Charles Viollette, Lille, F-59000, France
| | - Jacob G Malone
- John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK.
- University of East Anglia, Norwich, NR4 7TJ, UK.
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Pitino M, Armstrong CM, Cano LM, Duan Y. Transient Expression of Candidatus Liberibacter Asiaticus Effector Induces Cell Death in Nicotiana benthamiana. FRONTIERS IN PLANT SCIENCE 2016; 7:982. [PMID: 27458468 PMCID: PMC4933711 DOI: 10.3389/fpls.2016.00982] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Accepted: 06/21/2016] [Indexed: 05/19/2023]
Abstract
Candidatus Liberibacter asiaticus "Las" is a phloem-limited bacterial plant pathogen, and the most prevalent species of Liberibacter associated with citrus huanglongbing (HLB), a devastating disease of citrus worldwide. Although, the complete sequence of the Las genome provides the basis for studying functional genomics of Las and molecular mechanisms of Las-plant interactions, the functional characterization of Las effectors remains a slow process since remains to be cultured. Like other plant pathogens, Las may deliver effector proteins into host cells and modulate a variety of host cellular functions for their infection progression. In this study, we identified 16 putative Las effectors via bioinformatics, and transiently expressed them in Nicotiana benthamiana. Diverse subcellular localization with different shapes and aggregation patterns of the effector candidates were revealed by UV- microscopy after transient expression in leaf tissue. Intriguingly, one of the 16 candidates, Las5315mp (mature protein), was localized in the chloroplast and induced cell death at 3 days post inoculation (dpi) in N. benthamiana. Moreover, Las5315mp induced strong callose deposition in plant cells. This study provides new insights into the localizations and potential roles of these Las effectors in planta.
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Affiliation(s)
- Marco Pitino
- U.S. Horticultural Research Laboratory, Agricultural Research Service, United States Department of AgricultureFort Pierce, FL, USA
| | - Cheryl M. Armstrong
- U.S. Horticultural Research Laboratory, Agricultural Research Service, United States Department of AgricultureFort Pierce, FL, USA
| | - Liliana M. Cano
- Institute of Food and Agricultural Sciences, Department of Plant Pathology, Indian River Research and Education Center, University of FloridaFort Pierce, FL, USA
| | - Yongping Duan
- U.S. Horticultural Research Laboratory, Agricultural Research Service, United States Department of AgricultureFort Pierce, FL, USA
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