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Wang Q, Hu F, Yao Z, Zhao X, Chu G, Ye J. Comprehensive genomic characterisation of the NAC transcription factor family and its response to drought stress in Eucommia ulmoides. PeerJ 2023; 11:e16298. [PMID: 37901460 PMCID: PMC10601904 DOI: 10.7717/peerj.16298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Accepted: 09/23/2023] [Indexed: 10/31/2023] Open
Abstract
The NAC transcription factor family enhances plant adaptation to environmental challenges by participating in signalling pathways triggered by abiotic stressors and hormonal cues. We identified 69 NAC genes in the Eucommia ulmoides genome and renamed them according to their chromosomal distribution. These EuNAC proteins were clustered into 13 sub-families and distributed on 16 chromosomes and 2 scaffolds. The gene structures suggested that the number of exons varied from two to eight among these EuNACs, with a multitude of them containing three exons. Duplicated events resulted in a large gene family; 12 and four pairs of EuNACs were the result of segmental and tandem duplicates, respectively. The drought-stress response pattern of 12 putative EuNACs was observed under drought treatment, revealing that these EuNACs could play crucial roles in mitigating the effects of drought stress responses and serve as promising candidate genes for genetic engineering aimed at enhancing the drought stress tolerance of E. ulmoides. This study provides insight into the evolution, diversity, and characterisation of NAC genes in E. ulmoides and will be helpful for future characterisation of putative EuNACs associated with water deficit.
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Affiliation(s)
- Qi Wang
- Laboratory of Forestry Department, Agricultural College, Shihezi University, Shihezi, China
| | - FengCheng Hu
- Lveyang County Forest Tree Seedling Workstation, Forestry Bureau of Lveyang County, Lveyang, China
| | - ZhaoQun Yao
- Laboratory of Plant Protection Department, Agricultural College, Shihezi University, Shihezi, China
| | - XinFeng Zhao
- Lveyang County Forest Tree Seedling Workstation, Forestry Bureau of Lveyang County, Lveyang, China
| | - GuangMing Chu
- Laboratory of Forestry Department, Agricultural College, Shihezi University, Shihezi, China
| | - Jing Ye
- Laboratory of Forestry Department, Agricultural College, Shihezi University, Shihezi, China
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Jeong HW, Ryu TH, Lee HJ, Kim KH, Jeong RD. DNA Damage Triggers the Activation of Immune Response to Viral Pathogens via Salicylic Acid in Plants. THE PLANT PATHOLOGY JOURNAL 2023; 39:449-465. [PMID: 37817492 PMCID: PMC10580055 DOI: 10.5423/ppj.oa.08.2023.0112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 09/04/2023] [Accepted: 09/06/2023] [Indexed: 10/12/2023]
Abstract
Plants are challenged by various pathogens throughout their lives, such as bacteria, viruses, fungi, and insects; consequently, they have evolved several defense mechanisms. In addition, plants have developed localized and systematic immune responses due to biotic and abiotic stress exposure. Animals are known to activate DNA damage responses (DDRs) and DNA damage sensor immune signals in response to stress, and the process is well studied in animal systems. However, the links between stress perception and immune response through DDRs remain largely unknown in plants. To determine whether DDRs induce plant resistance to pathogens, Arabidopsis plants were treated with bleomycin, a DNA damage-inducing agent, and the replication levels of viral pathogens and growth of bacterial pathogens were determined. We observed that DDR-mediated resistance was specifically activated against viral pathogens, including turnip crinkle virus (TCV). DDR increased the expression level of pathogenesis-related (PR) genes and the total salicylic acid (SA) content and promoted mitogen-activated protein kinase signaling cascades, including the WRKY signaling pathway in Arabidopsis. Transcriptome analysis further revealed that defense- and SA-related genes were upregulated by DDR. The atm-2atr-2 double mutants were susceptible to TCV, indicating that the main DDR signaling pathway sensors play an important role in plant immune responses. In conclusion, DDRs activated basal immune responses to viral pathogens.
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Affiliation(s)
- Hwi-Won Jeong
- Department of Applied Biology, Chonnam National University, Gwangju 61185, Korea
| | - Tae Ho Ryu
- Department of Applied Biology, Chonnam National University, Gwangju 61185, Korea
| | - Hyo-Jeong Lee
- Department of Applied Biology, Chonnam National University, Gwangju 61185, Korea
| | - Kook-Hyung Kim
- Department of Agricultural Biotechnology, College of Agriculture and Life Sciences, Seoul National University, Seoul 08826, Korea
| | - Rae-Dong Jeong
- Department of Applied Biology, Chonnam National University, Gwangju 61185, Korea
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3
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Li T, Cheng X, Wang X, Li G, Wang B, Wang W, Zhang N, Han Y, Jiao B, Wang Y, Liu G, Xu T, Xu Y. Glyoxalase I-4 functions downstream of NAC72 to modulate downy mildew resistance in grapevine. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 108:394-410. [PMID: 34318550 DOI: 10.1111/tpj.15447] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Revised: 07/20/2021] [Accepted: 07/22/2021] [Indexed: 05/09/2023]
Abstract
Glyoxalase I (GLYI) is part of the glyoxalase system; its major function is the detoxification of α-ketoaldehydes, including the potent and cytotoxic methylglyoxal (MG). Methylglyoxal disrupts mitochondrial respiration and increases production of reactive oxygen species (ROS), which also increase during pathogen infection of plant tissues; however, there have been few studies relating the glyoxalase system to the plant pathogen response. We used the promoter of VvGLYI-4 to screen the upstream transcription factors and report a NAC (NAM/ATAF/CUC) domain-containing transcription factor VvNAC72 in grapevine, which is localized to the nucleus. Our results show that VvNAC72 expression is induced by downy mildew, Plasmopara viticola, while the transcript level of VvGLYI-4 decreases. Further analysis revealed that VvNAC72 can bind directly to the promoter region of VvGLYI-4 via the CACGTG element, leading to inhibition of VvGLYI-4 transcription. Stable overexpression of VvNAC72 in grapevine and tobacco showed a decreased expression level of VvGLYI-4 and increased content of MG and ROS, as well as stronger resistance to pathogen stress. Taken together, these results demonstrate that grapevine VvNAC72 negatively modulates detoxification of MG through repression of VvGLYI-4, and finally enhances resistance to downy mildew, at least in part, via the modulation of MG-associated ROS homeostasis through a salicylic acid-mediated defense pathway.
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Affiliation(s)
- Tiemei Li
- State Key Laboratory of Crop Stress Biology for Arid Areas, 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, Yangling, Shaanxi, 712100, China
| | - Xin Cheng
- State Key Laboratory of Crop Stress Biology for Arid Areas, 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, Yangling, Shaanxi, 712100, China
| | - Xiaowei Wang
- State Key Laboratory of Crop Stress Biology for Arid Areas, 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, Yangling, Shaanxi, 712100, China
| | - Guanggui Li
- State Key Laboratory of Crop Stress Biology for Arid Areas, 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, Yangling, Shaanxi, 712100, China
| | - Bianbian Wang
- State Key Laboratory of Crop Stress Biology for Arid Areas, 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, Yangling, Shaanxi, 712100, China
| | - Wenyuan Wang
- State Key Laboratory of Crop Stress Biology for Arid Areas, 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, Yangling, Shaanxi, 712100, China
| | - Na Zhang
- State Key Laboratory of Crop Stress Biology for Arid Areas, 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, Yangling, Shaanxi, 712100, China
| | - Yulei Han
- State Key Laboratory of Crop Stress Biology for Arid Areas, 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, Yangling, Shaanxi, 712100, China
| | - Bolei Jiao
- State Key Laboratory of Crop Stress Biology for Arid Areas, 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, Yangling, Shaanxi, 712100, China
| | - Yuejin Wang
- State Key Laboratory of Crop Stress Biology for Arid Areas, 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, Yangling, Shaanxi, 712100, China
| | - Guotian Liu
- State Key Laboratory of Crop Stress Biology for Arid Areas, 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, Yangling, Shaanxi, 712100, China
| | - Tengfei Xu
- State Key Laboratory of Crop Stress Biology for Arid Areas, 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, Yangling, Shaanxi, 712100, China
| | - Yan Xu
- State Key Laboratory of Crop Stress Biology for Arid Areas, 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, Yangling, Shaanxi, 712100, China
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Herath V, Verchot J. Transcriptional Regulatory Networks Associate with Early Stages of Potato Virus X Infection of Solanum tuberosum. Int J Mol Sci 2021; 22:2837. [PMID: 33799566 PMCID: PMC8001266 DOI: 10.3390/ijms22062837] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 03/04/2021] [Accepted: 03/09/2021] [Indexed: 11/16/2022] Open
Abstract
Potato virus X (PVX) belongs to genus Potexvirus. This study characterizes the cellular transcriptome responses to PVX infection in Russet potato at 2 and 3 days post infection (dpi). Among the 1242 differentially expressed genes (DEGs), 268 genes were upregulated, and 37 genes were downregulated at 2 dpi while 677 genes were upregulated, and 265 genes were downregulated at 3 dpi. DEGs related to signal transduction, stress response, and redox processes. Key stress related transcription factors were identified. Twenty-five pathogen resistance gene analogs linked to effector triggered immunity or pathogen-associated molecular pattern (PAMP)-triggered immunity were identified. Comparative analysis with Arabidopsis unfolded protein response (UPR) induced DEGs revealed genes associated with UPR and plasmodesmata transport that are likely needed to establish infection. In conclusion, this study provides an insight on major transcriptional regulatory networked involved in early response to PVX infection and establishment.
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Affiliation(s)
- Venura Herath
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77802, USA;
- Department of Agriculture Biology, Faculty of Agriculture, University of Peradeniya, Peradeniya 20400, Sri Lanka
| | - Jeanmarie Verchot
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77802, USA;
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5
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Munir N, Yukun C, Xiaohui C, Nawaz MA, Iftikhar J, Rizwan HM, Xu S, Yuling L, Xuhan X, Zhongxiong L. Genome-wide identification and comprehensive analyses of NAC transcription factor gene family and expression patterns during somatic embryogenesis in Dimocarpus longan Lour. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2020; 157:169-184. [PMID: 33120109 DOI: 10.1016/j.plaphy.2020.10.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2020] [Accepted: 10/06/2020] [Indexed: 05/23/2023]
Abstract
The NAM, ATAF1/2, and CUC2 form a huge plant-specific gene family of NAC TFs that are involved in the growth, development, and regulation of biotic and abiotic stress responses. Although the draft genome of longan (Dimocarpus longan Lour.) has been published, however the comprehensive data regarding the functions, evolution, and expression patterns of the NAC family are still unavailable. In this study, a comprehensive analysis of the NAC transcription factor family in longan was performed, and a total of 114 NAC genes were found. We investigated the NAC gene family exploring the phylogeny, domain conservation, intron/exon, motifs, cis-regulatory elements, protein-protein interaction, and expression profiles of RNA-seq samples in different tissues and early somatic embryogenesis of longan. Phylogenetic analysis showed that the genes with similar gene structure and motif distribution were clustered in the same group. Cis-element identification indicates the possible role of NAC genes in biological and physiological processes. Protein-protein interaction identified the DlNACs homologous with Arabidopsis proteins. We further investigated the expression pattern of DlNAC genes in different tissues (pulp, stem, large fruit, young fruit, and flower) during somatic embryogenesis at embryogenic callus (EC), incomplete compact pro-embryogenic cultures (ICpEC), and globular embryos (GE) stages. The qRT-PCR results showed that the DlNAC genes were expressed higher at EC and GE stage compared with ICpEC stage. In conclusion, our results provide insight into the evolution, diversity, and characterization of NAC genes in the longan and provide a base for understanding their biological roles and molecular mechanisms in plants.
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Affiliation(s)
- Nigarish Munir
- Institute of Horticultural Biotechnology, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Chen Yukun
- Institute of Horticultural Biotechnology, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Chen Xiaohui
- Institute of Horticultural Biotechnology, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Muhammad Azher Nawaz
- Department of Horticulture, College of Agriculture, University of Sargodha, Sargodha, 40100, Pakistan
| | - Junaid Iftikhar
- Fujian Provincial Key Laboratory of Plant Functional Biology, College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Hafiz Muhammad Rizwan
- Institute of Subtropical Fruit, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Shen Xu
- Institute of Horticultural Biotechnology, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Lin Yuling
- Institute of Horticultural Biotechnology, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Xu Xuhan
- Institute of Horticultural Biotechnology, Fujian Agriculture and Forestry University, Fuzhou, 350002, China; Institute de la Recherché Interdisciplinary de Toulouse, IRIT-ARI, 31300, Toulouse, France.
| | - Lai Zhongxiong
- Institute of Horticultural Biotechnology, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.
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6
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Kapos P, Devendrakumar KT, Li X. Plant NLRs: From discovery to application. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2019; 279:3-18. [PMID: 30709490 DOI: 10.1016/j.plantsci.2018.03.010] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 03/01/2018] [Accepted: 03/02/2018] [Indexed: 05/09/2023]
Abstract
Plants require a complex immune system to defend themselves against a wide range of pathogens which threaten their growth and development. The nucleotide-binding leucine-rich repeat proteins (NLRs) are immune sensors that recognize effectors delivered by pathogens. The first NLR was cloned more than twenty years ago. Since this initial discovery, NLRs have been described as key components of plant immunity responsible for pathogen recognition and triggering defense responses. They have now been described in most of the well-studied mulitcellular plant species, with most having large NLR repertoires. As research has progressed so has the understanding of how NLRs interact with their recognition substrates and how they in turn activate downstream signalling. It has also become apparent that NLR regulation occurs at the transcriptional, post-transcriptional, translational, and post-translational levels. Even before the first NLR was cloned, breeders were utilising such genes to increase crop performance. Increased understanding of the mechanistic details of the plant immune system enable the generation of plants resistant against devastating pathogens. This review aims to give an updated summary of the NLR field.
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Affiliation(s)
- Paul Kapos
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada; Department of Botany, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Karen Thulasi Devendrakumar
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada; Department of Botany, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Xin Li
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada; Department of Botany, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada.
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7
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Lim GH, Hoey T, Zhu S, Clavel M, Yu K, Navarre D, Kachroo A, Deragon JM, Kachroo P. COP1, a negative regulator of photomorphogenesis, positively regulates plant disease resistance via double-stranded RNA binding proteins. PLoS Pathog 2018; 14:e1006894. [PMID: 29513740 PMCID: PMC5871017 DOI: 10.1371/journal.ppat.1006894] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2017] [Revised: 03/27/2018] [Accepted: 01/22/2018] [Indexed: 11/18/2022] Open
Abstract
The E3 ubiquitin ligase COP1 (Constitutive Photomorphogenesis 1) is a well known component of the light-mediated plant development that acts as a repressor of photomorphogenesis. Here we show that COP1 positively regulates defense against turnip crinkle virus (TCV) and avrRPM1 bacteria by contributing to stability of resistance (R) protein HRT and RPM1, respectively. HRT and RPM1 levels and thereby pathogen resistance is significantly reduced in the cop1 mutant background. Notably, the levels of at least two double-stranded RNA binding (DRB) proteins DRB1 and DRB4 are reduced in the cop1 mutant background suggesting that COP1 affects HRT stability via its effect on the DRB proteins. Indeed, a mutation in either drb1 or drb4 resulted in degradation of HRT. In contrast to COP1, a multi-subunit E3 ligase encoded by anaphase-promoting complex (APC) 10 negatively regulates DRB4 and TCV resistance but had no effect on DRB1 levels. We propose that COP1-mediated positive regulation of HRT is dependent on a balance between COP1 and negative regulators that target DRB1 and DRB4.
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Affiliation(s)
- Gah-Hyun Lim
- Department of Plant Pathology, University of Kentucky, Lexington, KY, United States of America
| | - Timothy Hoey
- Department of Plant Pathology, University of Kentucky, Lexington, KY, United States of America
| | - Shifeng Zhu
- Department of Plant Pathology, University of Kentucky, Lexington, KY, United States of America
| | - Marion Clavel
- Université de Perpignan Via Domitia, CNRS UMR5096 LGDP, Perpignan, France
| | - Keshun Yu
- Department of Plant Pathology, University of Kentucky, Lexington, KY, United States of America
| | - Duroy Navarre
- U.S. Department of Agriculture–Agricultural Research Service, Washington State University, Prosser, WA, United States of America
| | - Aardra Kachroo
- Department of Plant Pathology, University of Kentucky, Lexington, KY, United States of America
| | - Jean-Marc Deragon
- Université de Perpignan Via Domitia, CNRS UMR5096 LGDP, Perpignan, France
| | - Pradeep Kachroo
- Department of Plant Pathology, University of Kentucky, Lexington, KY, United States of America
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8
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Moffett P. Transfer and modification of NLR proteins for virus resistance in plants. Curr Opin Virol 2017; 26:43-48. [DOI: 10.1016/j.coviro.2017.07.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 07/08/2017] [Accepted: 07/11/2017] [Indexed: 11/16/2022]
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9
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Wang G, Zhang S, Ma X, Wang Y, Kong F, Meng Q. A stress-associated NAC transcription factor (SlNAC35) from tomato plays a positive role in biotic and abiotic stresses. PHYSIOLOGIA PLANTARUM 2016; 158:45-64. [PMID: 26991441 DOI: 10.1111/ppl.12444] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Revised: 01/21/2016] [Accepted: 02/11/2016] [Indexed: 05/21/2023]
Abstract
The NAC transcription factor family participates in responses to various kinds of environmental stimuli in plants. Responses of NAC genes to abiotic stresses have been widely studied, but their functions in response to biotic stress are little reported in plants, especially in crops. In the present study, we examined the functions of a novel tomato (Solanum lycopersicum) NAC protein (SlNAC35) in abiotic and biotic stress resistance by using transgenic tobacco. Expression analysis found that SlNAC35 expression was induced by drought stress, salt stress, bacterial pathogen, and signaling molecules, suggesting its involvement in plant responses to biotic and abiotic stimuli. Moreover, transgenic lines exhibited a greater number of lateral roots and longer root length compared with Vec lines (empty vector lines) after drought and salt treatment. These results indicate that overexpression of SlNAC35 promoted root growth and development under drought and salt stresses. Higher expressions of NtARF1, NtARF2 and NtARF8 were observed under drought and salt stresses in transgenic lines, suggesting that overexpression of SlNAC35 promoted growth and development of roots in transgenic lines possibly by involving auxin signaling and by regulating NtARF expression. In addition, SlNAC35 overexpression improved resistance to bacterial pathogen in transgenic tobacco, and reactive oxygen species may be in the upstream of salicylic acid (SA) signaling in transgenic tobacco during defense response.
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Affiliation(s)
- Guodong Wang
- College of Life Science, State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai'an, P. R. China
| | - Song Zhang
- College of Life Science, State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai'an, P. R. China
| | - Xiaocui Ma
- College of Life Science, State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai'an, P. R. China
| | - Yong Wang
- College of Life Science, State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai'an, P. R. China
| | - Fanying Kong
- College of Life Science, State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai'an, P. R. China
| | - Qingwei Meng
- College of Life Science, State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai'an, P. R. China
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10
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Gao R, Liu P, Yong Y, Wong SM. Genome-wide transcriptomic analysis reveals correlation between higher WRKY61 expression and reduced symptom severity in Turnip crinkle virus infected Arabidopsis thaliana. Sci Rep 2016; 6:24604. [PMID: 27086702 PMCID: PMC4834565 DOI: 10.1038/srep24604] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Accepted: 04/01/2016] [Indexed: 11/16/2022] Open
Abstract
Turnip crinkle virus (TCV) is a carmovirus that infects many Arabidopsis ecotypes. Most studies mainly focused on discovery of resistance genes against TCV infection, and there is no Next Generation Sequencing based comparative genome wide transcriptome analysis reported. In this study, RNA-seq based transcriptome analysis revealed that 238 (155 up-regulated and 83 down-regulated) significant differentially expressed genes with at least 15-fold change were determined. Fifteen genes (including upregulated, unchanged and downregulated) were selected for RNA-seq data validation using quantitative real-time PCR, which showed consistencies between these two sets of data. GO enrichment analysis showed that numerous terms such as stress, immunity, defence and chemical stimulus were affected in TCV-infected plants. One putative plant defence related gene named WRKY61 was selected for further investigation. It showed that WRKY61 overexpression plants displayed reduced symptoms and less virus accumulation, as compared to wild type (WT) and WRKY61 deficient lines, suggesting that higher WRKY61 expression level reduced TCV viral accumulation. In conclusion, our transcriptome analysis showed that global gene expression was detected in TCV-infected Arabidopsis thaliana. WRKY61 gene was shown to be negatively correlated with TCV infection and viral symptoms, which may be connected to plant immunity pathways.
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Affiliation(s)
- Ruimin Gao
- Department of Biological Sciences, National University of Singapore, Singapore
| | - Peng Liu
- Department of Biological Sciences, National University of Singapore, Singapore
| | - Yuhan Yong
- Department of Biological Sciences, National University of Singapore, Singapore
| | - Sek-Man Wong
- Department of Biological Sciences, National University of Singapore, Singapore.,Temasek Life Sciences Laboratory, Singapore.,National University of Singapore Suzhou Research Institute, Suzhou Industrial Park, Jiangsu, China
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11
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A nuclear fraction of turnip crinkle virus capsid protein is important for elicitation of the host resistance response. Virus Res 2015; 210:264-70. [PMID: 26299399 DOI: 10.1016/j.virusres.2015.08.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Revised: 08/11/2015] [Accepted: 08/15/2015] [Indexed: 11/21/2022]
Abstract
The N-terminal 25 amino acids (AAs) of turnip crinkle virus (TCV) capsid protein (CP) are recognized by the resistance protein HRT to trigger a hypersensitive response (HR) and systemic resistance to TCV infection. This same region of TCV CP also contains a motif that interacts with the transcription factor TIP, as well as a nuclear localization signal (NLS). However, it is not yet known whether nuclear localization of TCV CP is needed for the induction of HRT-mediated HR and resistance. Here we present new evidence suggesting a tight correlation between nuclear inclusions formed by CP and the manifestation of HR. We show that a fraction of TCV CP localized to cell nuclei to form discrete inclusion-like structures, and a mutated CP (R6A) known to abolish HR failed to form nuclear inclusions. Notably, TIP-CP interaction augments the inclusion-forming activity of CP by tethering inclusions to the nuclear membrane. This TIP-mediated augmentation is also critical for HR resistance, as another CP mutant (R8A) known to elicit a less restrictive HR, though still self-associated into nuclear inclusions, failed to direct inclusions to the nuclear membrane due to its inability to interact with TIP. Finally, exclusion of CP from cell nuclei abolished induction of HR. Together, these results uncovered a strong correlation between nuclear localization and nuclear inclusion formation by TCV CP and induction of HR, and suggest that CP nuclear inclusions could be the key trigger of the HRT-dependent, yet TIP-reinforced, resistance to TCV.
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12
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Csorba T, Kontra L, Burgyán J. viral silencing suppressors: Tools forged to fine-tune host-pathogen coexistence. Virology 2015; 479-480:85-103. [DOI: 10.1016/j.virol.2015.02.028] [Citation(s) in RCA: 368] [Impact Index Per Article: 40.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Revised: 01/31/2015] [Accepted: 02/16/2015] [Indexed: 12/27/2022]
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13
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Kang SH, Qu F, Morris TJ. A spectrum of HRT-dependent hypersensitive responses elicited by the 52 amino acid N-terminus of turnip crinkle virus capsid protein and its mutants. Virus Res 2015; 200:30-4. [PMID: 25656064 DOI: 10.1016/j.virusres.2015.01.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Revised: 01/21/2015] [Accepted: 01/24/2015] [Indexed: 11/28/2022]
Abstract
The capsid protein (CP) of turnip crinkle virus (TCV) is the elicitor of hypersensitive response (HR) and resistance mediated by the resistance protein HRT in the Di-17 ecotype of Arabidopsis. Here we identified the N-terminal 52-amino-acid R domain of TCV CP as the elicitor of HRT-dependent HR in Nicotiana benthamiana. Mutating this domain at position 6 (R6A), but not at positions 8 (R8A) or 14 (G14A), abolished HR in N. benthamiana. However, on Di-17 Arabidopsis leaves only R8A R domain elicited visible epidermal HR. When incorporated in infectious TCV RNAs, R8A and G14A mutations exerted dramatically different effects in Di-17 plants, as R8A caused systemic cell death whereas G14A led to complete restriction of the mutant virus. This continual spectrum of HR and resistance responses elicited by various R domain mutants suggests that the CP-HRT interaction could be perturbed by conformational changes in the R domain of TCV CP.
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Affiliation(s)
- Sung-Hwan Kang
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, NE 68588, United States
| | - Feng Qu
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, NE 68588, United States; Department of Plant Pathology, The Ohio State University, Wooster, OH 44691, United States.
| | - T Jack Morris
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, NE 68588, United States.
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14
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Niu D, Wang Z, Wang S, Qiao L, Zhao H. Profiling of small RNAs involved in plant-pathogen interactions. Methods Mol Biol 2015; 1287:61-79. [PMID: 25740356 DOI: 10.1007/978-1-4939-2453-0_4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Small RNA (sRNA)-mediated gene silencing is an important gene expression regulatory mechanism conserved in eukaryotes. Such sRNAs, first discovered in plants, are involved in diverse biological processes. In plants, sRNAs participate in many growth and developmental processes, such as embryo development, seed germination, flowering, hormone synthesis and distribution, and nutrient assimilation. However, the significance of sRNA in shaping the relationship between plants and their symbiotic microbes or pathogens has been underestimated. Recent progress in profiling sRNA, especially advances in next-generation sequencing technology, has revealed its extensive and complicated involvement in interactions between plants and viruses, bacteria, and fungi. In this review, we will summarize recent findings regarding sRNA in plant-pathogen interactions.
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Affiliation(s)
- Dongdong Niu
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Xuanwu, Nanjing, Jiangsu, 210095, China
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15
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The capsid protein p38 of turnip crinkle virus is associated with the suppression of cucumber mosaic virus in Arabidopsis thaliana co-infected with cucumber mosaic virus and turnip crinkle virus. Virology 2014; 462-463:71-80. [DOI: 10.1016/j.virol.2014.05.031] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Revised: 05/09/2014] [Accepted: 05/27/2014] [Indexed: 11/20/2022]
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16
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Nakahara KS, Masuta C. Interaction between viral RNA silencing suppressors and host factors in plant immunity. CURRENT OPINION IN PLANT BIOLOGY 2014; 20:88-95. [PMID: 24875766 DOI: 10.1016/j.pbi.2014.05.004] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Revised: 04/24/2014] [Accepted: 05/01/2014] [Indexed: 05/18/2023]
Abstract
To elucidate events in the molecular arms race between the host and pathogen in evaluating plant immunity, a zigzag model is useful for uncovering aspects common to different host-pathogen interactions. By analogy of the steps in virus-host interactions with the steps in the standard zigzag model outlined in recent papers, we may regard RNA silencing as pattern-triggered immunity (PTI) against viruses, RNA silencing suppressors (RSSs) as effectors to overcome host RNA silencing and resistance gene (R-gene)-mediated defense as effector-triggered immunity (ETI) recognizing RSSs as avirulence proteins. However, because the standard zigzag model does not fully apply to some unique aspects in the interactions between a plant host and virus, we here defined a model especially designed for viruses. Although we simplified the phenomena involved in the virus-host interactions in the model, certain specific interactive steps can be explained by integrating additional host factors into the model. These host factors are thought to play an important role in maintaining the efficacy of the various steps in the main pathway of defense against viruses in this model for virus-plant interactions. For example, we propose candidates that may interact with viral RSSs to induce the resistance response.
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Affiliation(s)
- Kenji S Nakahara
- Plant Breeding Science, Research Faculty of Agriculture, Hokkaido University, Sapporo, 060-8589, Japan.
| | - Chikara Masuta
- Plant Breeding Science, Research Faculty of Agriculture, Hokkaido University, Sapporo, 060-8589, Japan.
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17
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Zhu S, Lim GH, Yu K, Jeong RD, Kachroo A, Kachroo P. RNA silencing components mediate resistance signaling against turnip crinkle virus. PLANT SIGNALING & BEHAVIOR 2014; 9:e28435. [PMID: 24614040 PMCID: PMC4091425 DOI: 10.4161/psb.28435] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2014] [Revised: 03/04/2014] [Accepted: 03/04/2014] [Indexed: 06/03/2023]
Abstract
Species-specific immunity is induced when an effector protein from a specific pathogen strain is perceived by a cognate resistance (R) protein in the plant. In Arabidopsis, the R protein HRT, which confers resistance to turnip crinkle virus (TCV), is activated upon recognition of the TCV coat-protein (CP), a potent suppressor of host RNA silencing. Recognition by HRT does not require RNA silencing suppressor function of CP and is not associated with the accumulation of TCV-specific small-RNA. However, several components of the host RNA silencing pathway participate in HRT-mediated defense against TCV. For example, the double stranded RNA binding protein (DRB) 4 interacts with the plasma membrane localized HRT, and is required for its stability. Intriguingly, TCV infection promotes the cytosolic accumulation of the otherwise primarily nuclear DRB4, and this in turn inhibits HRT-DRB4 interaction. These data together with differential localization of DRB4 in plants inoculated with avirulent and virulent viruses, suggests that sub-cellular compartmentalization of DRB4 plays an important role in activation of HRT.
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Affiliation(s)
- Shifeng Zhu
- † Current affiliation: Department of Plant Biology and Ecology; College of Life Sciences; Nankai University; Tianjin, PR China
| | - Gah-Hyun Lim
- Department of Plant Pathology; University of Kentucky; Lexington, KY USA
| | - Keshun Yu
- Department of Plant Pathology; University of Kentucky; Lexington, KY USA
| | - Rae-Dong Jeong
- ‡ Current affiliation: Korea Atomic Energy Research Institute; Jeongeup si Jeonlabukdo, South Korea
| | - Aardra Kachroo
- Department of Plant Pathology; University of Kentucky; Lexington, KY USA
| | - Pradeep Kachroo
- Department of Plant Pathology; University of Kentucky; Lexington, KY USA
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18
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de Ronde D, Pasquier A, Ying S, Butterbach P, Lohuis D, Kormelink R. Analysis of Tomato spotted wilt virus NSs protein indicates the importance of the N-terminal domain for avirulence and RNA silencing suppression. MOLECULAR PLANT PATHOLOGY 2014; 15:185-95. [PMID: 24103150 PMCID: PMC6638762 DOI: 10.1111/mpp.12082] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Recently, Tomato spotted wilt virus (TSWV) nonstructural protein NSs has been identified unambiguously as an avirulence (Avr) determinant for Tomato spotted wilt (Tsw)-based resistance. The observation that NSs from two natural resistance-breaking isolates had lost RNA silencing suppressor (RSS) activity and Avr suggested a link between the two functions. To test this, a large set of NSs mutants was generated by alanine substitutions in NSs from resistance-inducing wild-type strains (NSs(RI) ), amino acid reversions in NSs from resistance-breaking strains (NSs(RB)), domain deletions and swapping. Testing these mutants for their ability to suppress green fluorescent protein (GFP) silencing and to trigger a Tsw-mediated hypersensitive response (HR) revealed that the two functions can be separated. Changes in the N-terminal domain were found to be detrimental for both activities and indicated the importance of this domain, additionally supported by domain swapping between NSs(RI) and NSs(RB). Swapping domains between the closely related Tospovirus Groundnut ringspot virus (GRSV) NSs and TSWV NSs(RI) showed that Avr functionality could not simply be transferred between species. Although deletion of the C-terminal domain rendered NSs completely dysfunctional, only a few single-amino-acid mutations in the C-terminus affected both functions. Mutation of a GW/WG motif (position 17/18) rendered NSs completely dysfunctional for RSS and Avr activity, and indicated a putative interaction between NSs and Argonaute 1 (AGO1), and its importance in TSWV virulence and viral counter defence against RNA interference.
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Affiliation(s)
- Dryas de Ronde
- Laboratory of Virology, Department of Plant Sciences, Wageningen University, Droevendaalsesteeg 1, 6708 PB, Wageningen, the Netherlands
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19
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Donze T, Qu F, Twigg P, Morris TJ. Turnip crinkle virus coat protein inhibits the basal immune response to virus invasion in Arabidopsis by binding to the NAC transcription factor TIP. Virology 2013; 449:207-14. [PMID: 24418554 DOI: 10.1016/j.virol.2013.11.018] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Revised: 11/01/2013] [Accepted: 11/10/2013] [Indexed: 10/25/2022]
Abstract
Turnip crinkle virus (TCV) has been shown to interact with a NAC transcription factor, TIP, of Arabidopsis thaliana, via its coat protein (CP). This interaction correlates with the resistance response manifested in TCV-resistant Arabidopsis ecotype Di-17. We report that failure of a mutated CP to interact with TIP triggered the corresponding TCV mutant (R6A) to cause more severe symptoms in the TCV-susceptible ecotype Col-0. We hypothesized that TCV regulates antiviral basal immunity through TIP-CP interaction. Consistent with this hypothesis, we found that the rate of accumulation of R6A was measurably slower than wild-type TCV over the course of an infection. Notably, R6A was able to accumulate at similar rates as wild-type TCV in mutant plants with defects in salicylic acid (SA) signaling. Finally, plants with altered TIP expression provided evidence R6A's inability to evade the basal resistance response was likely associated with loss of ability for CP to bind TIP.
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Affiliation(s)
- Teresa Donze
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, NE 68588, USA
| | - Feng Qu
- Department of Plant Pathology, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster, OH 44691, USA
| | - Paul Twigg
- Biology Department, University of Nebraska-Kearney, Kearney, NE 68849, USA
| | - T Jack Morris
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, NE 68588, USA.
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20
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Zhu S, Jeong RD, Lim GH, Yu K, Wang C, Chandra-Shekara AC, Navarre D, Klessig DF, Kachroo A, Kachroo P. Double-stranded RNA-binding protein 4 is required for resistance signaling against viral and bacterial pathogens. Cell Rep 2013; 4:1168-84. [PMID: 24055058 DOI: 10.1016/j.celrep.2013.08.018] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Revised: 07/19/2013] [Accepted: 08/08/2013] [Indexed: 11/27/2022] Open
Abstract
Plant viruses often encode suppressors of host RNA silencing machinery, which occasionally function as avirulence factors that are recognized by host resistance (R) proteins. For example, the Arabidopsis R protein, hypersensitive response to TCV (HRT), recognizes the turnip crinkle virus (TCV) coat protein (CP). HRT-mediated resistance requires the RNA-silencing component double-stranded RNA-binding protein 4 (DRB4) even though it neither is associated with the accumulation of TCV-specific small RNA nor requires the RNA silencing suppressor function of CP. HRT interacts with the cytosolic fraction of DRB4. Interestingly, TCV infection both increases the cytosolic DRB4 pool and inhibits the HRT-DRB4 interaction. The virulent R8A CP derivative, which induces a subset of HRT-derived responses, also disrupts this interaction. The differential localization of DRB4 in the presence of wild-type and R8A CP implies the importance of subcellular compartmentalization of DRB4. The requirement of DRB4 in resistance to bacterial infection suggests a universal role in R-mediated defense signaling.
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Affiliation(s)
- Shifeng Zhu
- Department of Plant Pathology, University of Kentucky, Lexington, KY 40546, USA
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21
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Nuruzzaman M, Sharoni AM, Kikuchi S. Roles of NAC transcription factors in the regulation of biotic and abiotic stress responses in plants. Front Microbiol 2013; 4:248. [PMID: 24058359 PMCID: PMC3759801 DOI: 10.3389/fmicb.2013.00248] [Citation(s) in RCA: 435] [Impact Index Per Article: 39.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Accepted: 08/05/2013] [Indexed: 12/25/2022] Open
Abstract
NAC transcription factors are one of the largest families of transcriptional regulators in plants, and members of the NAC gene family have been suggested to play important roles in the regulation of the transcriptional reprogramming associated with plant stress responses. A phylogenetic analysis of NAC genes, with a focus on rice and Arabidopsis, was performed. Herein, we present an overview of the regulation of the stress responsive NAC SNAC/(IX) group of genes that are implicated in the resistance to different stresses. SNAC factors have important roles for the control of biotic and abiotic stresses tolerance and that their overexpression can improve stress tolerance via biotechnological approaches. We also review the recent progress in elucidating the roles of NAC transcription factors in plant biotic and abiotic stresses. Modification of the expression pattern of transcription factor genes and/or changes in their activity contribute to the elaboration of various signaling pathways and regulatory networks. However, a single NAC gene often responds to several stress factors, and their protein products may participate in the regulation of several seemingly disparate processes as negative or positive regulators. Additionally, the NAC proteins function via auto-regulation or cross-regulation is extensively found among NAC genes. These observations assist in the understanding of the complex mechanisms of signaling and transcriptional reprogramming controlled by NAC proteins.
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Affiliation(s)
- Mohammed Nuruzzaman
- Plant Genome Research Unit, Division of Genome and Biodiversity Research, Agrogenomics Research Center, National Institute of Agrobiological Sciences Tsukuba, Japan ; Graduate School of Science and Engineering, Institute for Environmental Science and Technology, Saitama University Saitama, Japan
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22
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Non-encapsidation activities of the capsid proteins of positive-strand RNA viruses. Virology 2013; 446:123-32. [PMID: 24074574 PMCID: PMC3818703 DOI: 10.1016/j.virol.2013.07.023] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Revised: 07/11/2013] [Accepted: 07/20/2013] [Indexed: 02/08/2023]
Abstract
Viral capsid proteins (CPs) are characterized by their role in forming protective shells around viral genomes. However, CPs have additional and important roles in the virus infection cycles and in the cellular responses to infection. These activities involve CP binding to RNAs in both sequence-specific and nonspecific manners as well as association with other proteins. This review focuses on CPs of both plant and animal-infecting viruses with positive-strand RNA genomes. We summarize the structural features of CPs and describe their modulatory roles in viral translation, RNA-dependent RNA synthesis, and host defense responses. We review regulatory activities of the capsid proteins of (+)-strand RNA viruses. Activities of capsid proteins due to RNA binding and protein binding. Effects of capsid proteins on viral processes. Effects of capsid proteins on cellular processes. Regulatory activities of the capsid proteins are affected by capsid concentrations.
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23
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Abstract
The frontline of plant defense against non-viral pathogens such as bacteria, fungi and oomycetes is provided by transmembrane pattern recognition receptors that detect conserved pathogen-associated molecular patterns (PAMPs), leading to pattern-triggered immunity (PTI). To counteract this innate defense, pathogens deploy effector proteins with a primary function to suppress PTI. In specific cases, plants have evolved intracellular resistance (R) proteins detecting isolate-specific pathogen effectors, leading to effector-triggered immunity (ETI), an amplified version of PTI, often associated with hypersensitive response (HR) and programmed cell death (PCD). In the case of plant viruses, no conserved PAMP was identified so far and the primary plant defense is thought to be based mainly on RNA silencing, an evolutionary conserved, sequence-specific mechanism that regulates gene expression and chromatin states and represses invasive nucleic acids such as transposons. Endogenous silencing pathways generate 21-24 nt small (s)RNAs, miRNAs and short interfering (si)RNAs, that repress genes post-transcriptionally and/or transcriptionally. Four distinct Dicer-like (DCL) proteins, which normally produce endogenous miRNAs and siRNAs, all contribute to the biogenesis of viral siRNAs in infected plants. Growing evidence indicates that RNA silencing also contributes to plant defense against non-viral pathogens. Conversely, PTI-based innate responses may contribute to antiviral defense. Intracellular R proteins of the same NB-LRR family are able to recognize both non-viral effectors and avirulence (Avr) proteins of RNA viruses, and, as a result, trigger HR and PCD in virus-resistant hosts. In some cases, viral Avr proteins also function as silencing suppressors. We hypothesize that RNA silencing and innate immunity (PTI and ETI) function in concert to fight plant viruses. Viruses counteract this dual defense by effectors that suppress both PTI-/ETI-based innate responses and RNA silencing to establish successful infection.
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Affiliation(s)
- Anna S Zvereva
- Institute of Botany, University of Basel, Schönbeinstrasse 6, 4056 Basel, Switzerland.
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24
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Puranik S, Sahu PP, Srivastava PS, Prasad M. NAC proteins: regulation and role in stress tolerance. TRENDS IN PLANT SCIENCE 2012; 17:369-81. [PMID: 22445067 DOI: 10.1016/j.tplants.2012.02.004] [Citation(s) in RCA: 599] [Impact Index Per Article: 49.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2011] [Revised: 01/31/2012] [Accepted: 02/16/2012] [Indexed: 05/17/2023]
Abstract
The plant-specific NAC (NAM, ATAF1,2 and CUC2) proteins constitute a major transcription factor family renowned for their roles in several developmental programs. Despite their highly conserved DNA-binding domains, their remarkable diversification across plants reflects their numerous functions. Lately, they have received much attention as regulators in various stress signaling pathways which may include interplay of phytohormones. This review summarizes the recent progress in research on NACs highlighting the proteins' potential for engineering stress tolerance against various abiotic and biotic challenges. We discuss regulatory components and targets of NAC proteins in the context of their prospective role for crop improvement strategies via biotechnological intervention.
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Affiliation(s)
- Swati Puranik
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi-110067, India
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25
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SAG101 forms a ternary complex with EDS1 and PAD4 and is required for resistance signaling against turnip crinkle virus. PLoS Pathog 2011; 7:e1002318. [PMID: 22072959 PMCID: PMC3207898 DOI: 10.1371/journal.ppat.1002318] [Citation(s) in RCA: 108] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2011] [Accepted: 08/31/2011] [Indexed: 11/19/2022] Open
Abstract
EDS1, PAD4, and SAG101 are common regulators of plant immunity against many pathogens. EDS1 interacts with both PAD4 and SAG101 but direct interaction between PAD4 and SAG101 has not been detected, leading to the suggestion that the EDS1-PAD4 and EDS1-SAG101 complexes are distinct. We show that EDS1, PAD4, and SAG101 are present in a single complex in planta. While this complex is preferentially nuclear localized, it can be redirected to the cytoplasm in the presence of an extranuclear form of EDS1. PAD4 and SAG101 can in turn, regulate the subcellular localization of EDS1. We also show that the Arabidopsis genome encodes two functionally redundant isoforms of EDS1, either of which can form ternary complexes with PAD4 and SAG101. Simultaneous mutations in both EDS1 isoforms are essential to abrogate resistance (R) protein-mediated defense against turnip crinkle virus (TCV) as well as avrRps4 expressing Pseudomonas syringae. Interestingly, unlike its function as a PAD4 substitute in bacterial resistance, SAG101 is required for R-mediated resistance to TCV, thus implicating a role for the ternary complex in this defense response. However, only EDS1 is required for HRT-mediated HR to TCV, while only PAD4 is required for SA-dependent induction of HRT. Together, these results suggest that EDS1, PAD4 and SAG101 also perform independent functions in HRT-mediated resistance. Plant immunity to pathogens requires several proteins, including EDS1, PAD4, SAG101, and these are thought to act downstream of resistance protein-mediated signaling. EDS1 interacts with both PAD4 and SAG101 but no interaction has been detected between SAG101 and PAD4. We show that SAG101 interacts with PAD4 via EDS1 and that the SAG101-EDS1-PAD4 ternary complex is present in the nucleus. EDS1, which is present in the cytoplasm and nucleus, is detected preferentially in the nucleus in the presence of SAG101. The presence of PAD4 restores the cytoplasmic localization of EDS1. Conversely, the SAG101-EDS1-PAD4 ternary complex, which is detected primarily in the nucleus, is redirected to cytoplasm in the presence of an extranuclear form of EDS1. These results show that protein localization changes in relation to the subcellular localization and/or relative levels of their interacting partners. We further show that Arabidopsis plants encode two functional isoforms of EDS1. Both isoforms interact with self and each other, as well as form ternary complexes. SAG101, which is thought to serve as a substitute for PAD4, functions independently in defense signaling against turnip crinkle virus. Our results suggest that EDS1, PAD4, SAG101 function independently as well as in a ternary complex to mediate plant defense signaling.
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26
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Jeong RD, Kachroo A, Kachroo P. Blue light photoreceptors are required for the stability and function of a resistance protein mediating viral defense in Arabidopsis. PLANT SIGNALING & BEHAVIOR 2010; 5:1504-9. [PMID: 21057210 PMCID: PMC3115268 DOI: 10.4161/psb.5.11.13705] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
This light-perciving ability of plants requires the activities of proteins termed photoreceptors. In addition to various growth and developmental processes, light also plays a role in plant defense against pathogens and is required for activation of several defense genes and regulation of the cell death response. However, the molecular or biochemical basis of light modulated regulation of defense signaling is largely unclear. We demonstrate a direct role for blue-light photoreceptors in resistance (R) protein-mediated plant defense against Turnip Crinkle Virus (TCV) in Arabidopsis. The blue-light photoreceptors, cryptochrome (CRY) 2 and phototropin (PHOT) 2, are specifically required for maintaining the stability of the R protein HRT, and thereby resistance to TCV. Exogenous application of the phytohormone salicylic acid elevates HRT levels in phot2 but not in cry2 background. These data indicate that CRY2 and PHOT2 function distinctly in maintaining post-transcriptional stability of HRT. HRT-mediated resistance is also dependent on CRY1 and PHOT1 proteins, but these do not contribute to the stability of HRT. HRT interacts with the CRY2/PHOT2-interacting protein COP1, a E3 ubiquitin ligase. Exogenous application of a proteasome inhibitor prevents blue-light-dependent degradation of HRT, suggesting that HRT is degraded via the 26S proteasome. These and the fact that PHOT2 interacts directly with the R protein RPS2 suggest that blue-light photoreceptors might be involved in regulation and/or signaling mediated by several R proteins.
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Affiliation(s)
- Rae-Dong Jeong
- Department of Plant Pathology, University of Kentucky, Lexington, KY, USA
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27
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Fraile A, García-Arenal F. The coevolution of plants and viruses: resistance and pathogenicity. Adv Virus Res 2010; 76:1-32. [PMID: 20965070 DOI: 10.1016/s0065-3527(10)76001-2] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Virus infection may damage the plant, and plant defenses are effective against viruses; thus, it is currently assumed that plants and viruses coevolve. However, and despite huge advances in understanding the mechanisms of pathogenicity and virulence in viruses and the mechanisms of virus resistance in plants, evidence in support of this hypothesis is surprisingly scant, and refers almost only to the virus partner. Most evidence for coevolution derives from the study of highly virulent viruses in agricultural systems, in which humans manipulate host genetic structure, what determines genetic changes in the virus population. Studies have focused on virus responses to qualitative resistance, either dominant or recessive but, even within this restricted scenario, population genetic analyses of pathogenicity and resistance factors are still scarce. Analyses of quantitative resistance or tolerance, which could be relevant for plant-virus coevolution, lag far behind. A major limitation is the lack of information on systems in which the host might evolve in response to virus infection, that is, wild hosts in natural ecosystems. It is presently unknown if, or under which circumstances, viruses do exert a selection pressure on wild plants, if qualitative resistance is a major defense strategy to viruses in nature, or even if characterized genes determining qualitative resistance to viruses did indeed evolve in response to virus infection. Here, we review evidence supporting plant-virus coevolution and point to areas in need of attention to understand the role of viruses in plant ecosystem dynamics, and the factors that determine virus emergence in crops.
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Affiliation(s)
- Aurora Fraile
- Centro de Biotecnología y Genómica de Plantas (UPM-INIA) and E.T.S.I. Agrónomos, Universidad Politécnica de Madrid, Campus de Montegancedo, Pozuelo de Alarcón, Madrid, Spain
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28
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Kang HG, Oh CS, Sato M, Katagiri F, Glazebrook J, Takahashi H, Kachroo P, Martin GB, Klessig DF. Endosome-associated CRT1 functions early in resistance gene-mediated defense signaling in Arabidopsis and tobacco. THE PLANT CELL 2010; 22:918-36. [PMID: 20332379 PMCID: PMC2861469 DOI: 10.1105/tpc.109.071662] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2009] [Revised: 02/10/2010] [Accepted: 03/09/2010] [Indexed: 05/18/2023]
Abstract
Resistance gene-mediated immunity confers protection against pathogen infection in a wide range of plants. A genetic screen for Arabidopsis thaliana mutants compromised for recognition of turnip crinkle virus previously identified CRT1, a member of the GHKL ATPase/kinase superfamily. Here, we demonstrate that CRT1 interacts with various resistance proteins from different structural classes, and this interaction is disrupted when these resistance proteins are activated. The Arabidopsis mutant crt1-2 crh1-1, which lacks CRT1 and its closest homolog, displayed compromised resistance to avirulent Pseudomonas syringae and Hyaloperonospora arabidopsidis. Additionally, resistance-associated hypersensitive cell death was suppressed in Nicotiana benthamiana silenced for expression of CRT1 homolog(s). Thus, CRT1 appears to be a general factor for resistance gene-mediated immunity. Since elevation of cytosolic calcium triggered by avirulent P. syringae was compromised in crt1-2 crh1-1 plants, but cell death triggered by Nt MEK2(DD) was unaffected in CRT1-silenced N. benthamiana, CRT1 likely functions at an early step in this pathway. Genome-wide transcriptome analysis led to identification of CRT1-Associated genes, many of which are associated with transport processes, responses to (a)biotic stress, and the endomembrane system. Confocal microscopy and subcellular fractionation revealed that CRT1 localizes to endosome-like vesicles, suggesting a key process in resistance protein activation/signaling occurs in this subcellular compartment.
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Affiliation(s)
- Hong-Gu Kang
- Boyce Thompson Institute for Plant Research, Ithaca, New York 14853
| | - Chang-Sik Oh
- Boyce Thompson Institute for Plant Research, Ithaca, New York 14853
| | - Masanao Sato
- Department of Plant Biology, University of Minnesota, St. Paul, Minnesota 55108
| | - Fumiaki Katagiri
- Department of Plant Biology, University of Minnesota, St. Paul, Minnesota 55108
| | - Jane Glazebrook
- Department of Plant Biology, University of Minnesota, St. Paul, Minnesota 55108
| | - Hideki Takahashi
- Department of Life Science, Tohoku University, Sendai 981-8555, Japan
| | - Pradeep Kachroo
- Department of Plant Pathology, University of Kentucky, Lexington, Kentucky 40546
| | - Gregory B. Martin
- Boyce Thompson Institute for Plant Research, Ithaca, New York 14853
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, New York 14853
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Abstract
One branch of plant innate immunity is mediated through what is traditionally known as race-specific or gene-for-gene resistance wherein the outcome of an attempted infection is determined by the genotypes of both the host and the pathogen. Dominant plant disease resistance (R) genes confer resistance to a variety of biotrophic pathogens, including viruses, encoding corresponding dominant avirulence (Avr) genes. R genes are among the most highly variable plant genes known, both within and between populations. Plant genomes encode hundreds of R genes that code for NB-LRR proteins, so named because they posses nucleotide-binding (NB) and leucine-rich repeat (LRR) domains. Many matching pairs of NB-LRR and Avr proteins have been identified as well as cellular proteins that mediate R/Avr interactions, and the molecular analysis of these interactions have led to the formulation of models of how products of R genes recognize pathogens. Data from multiple NB-LRR systems indicate that the LRR domains of NB-LRR proteins determine recognition specificity. However, recent evidence suggests that NB-LRR proteins have co-opted cellular recognition co-factors that mediate interactions between Avr proteins and the N-terminal domains of NB-LRR proteins.
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Wang X, Basnayake BMVS, Zhang H, Li G, Li W, Virk N, Mengiste T, Song F. The Arabidopsis ATAF1, a NAC transcription factor, is a negative regulator of defense responses against necrotrophic fungal and bacterial pathogens. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2009; 22:1227-38. [PMID: 19737096 DOI: 10.1094/mpmi-22-10-1227] [Citation(s) in RCA: 139] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Transcription factors of the NAC family are known to be involved in various growth or developmental processes and in regulation of response to environmental stresses. In the present study, we report that Arabidopsis ATAF1 is a negative regulator of defense responses against both necrotrophic fungal and bacterial pathogens. Expression of ATAF1 was downregulated after infection with Botrytis cinerea or Pseudomonas syringae pv. tomato or after treatment with salicylic acid (SA), jasmonic acid, and 1-amino cyclopropane-1-carboxylic acid (the precursor of ethylene biosynthesis). Transgenic plants that overexpress the ATAF1 gene (ATAF1-OE) showed increased susceptibility while expression of an ATAF1 chimeric repressor construct (ATAF1-SRDX) exhibited enhanced resistance to P. syringae pv. tomato DC3000, B. cinerea, and Alternaria brassicicola. The ataf1 mutant plants showed no significant resistance against the pathogens tested. After inoculation with B. cinerea or P. syringae pv. tomato DC3000, expressions of defense-related genes PR-1, PR-5. and PDF1.2 were upregulated in the ATAF1-SRDX plants but attenuated or unchanged in the ATAF1-OE plants. In ATAF1-OE plants, SA-induced expression of pathogenesis-related genes and disease resistance against P. syringae pv. tomato DC3000 was partially suppressed. Increased levels of reactive oxygen species (i.e., H(2)O(2) and superoxide anion) accumulated only in the ATAF1-OE but not in the ATAF1-SRDX plants after Botrytis spp. infection. Our studies provide direct genetic evidence for the role of ATAF1 as a negative regulator of defense response against different type of pathogens.
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Affiliation(s)
- Xiao'e Wang
- State Key Laboratory for Rice Biology, Institute of Biotechnology, Zhejiang University-Huajiachi Campus, Hangzhou, Zhejiang 310029, People's Republic of China
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Interaction of the Tobacco mosaic virus replicase protein with a NAC domain transcription factor is associated with the suppression of systemic host defenses. J Virol 2009; 83:9720-30. [PMID: 19625399 DOI: 10.1128/jvi.00941-09] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
An interaction between the helicase domain of the Tobacco mosaic virus (TMV) 126-/183-kDa replicase protein(s) and the Arabidopsis thaliana NAC domain transcription factor ATAF2 was identified via yeast two-hybrid and in planta immunoprecipitation assays. ATAF2 is transcriptionally induced in response to TMV infection, and its overexpression significantly reduces virus accumulation. Proteasome inhibition studies suggest that ATAF2 is targeted for degradation during virus infection. The transcriptional activity of known defense-associated marker genes PR1, PR2, and PDF1.2 significantly increase within transgenic plants overexpressing ATAF2. In contrast, these marker genes have reduced transcript levels in ATAF2 knockout or repressor plant lines. Thus, ATAF2 appears to function in the regulation of host basal defense responses. In response to TMV infections, ATAF2 and PR1 display increased transcript accumulations in inoculated tissues but not in systemically infected tissues. ATAF2 and PR1 transcript levels also increase in response to salicylic acid treatment. However, the salicylic acid treatment of systemically infected tissues did not produce a similar increase in either ATAF2 or PR1 transcripts, suggesting that host defense responses are attenuated during systemic virus invasion. Similarly, noninfected ATAF2 knockout or ATAF2 repressor lines display reduced levels of PR1 transcripts when treated with salicylic acid. Taken together, these findings suggest that the replicase-ATAF2 interaction suppresses basal host defenses as a means to promote systemic virus accumulation.
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