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Cao P, Shi H, Zhang S, Chen J, Wang R, Liu P, Zhu Y, An Y, Zhang M. A robust high-throughput functional screening assay for plant pathogen effectors using the TMV-GFP vector. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2024. [PMID: 38647454 DOI: 10.1111/tpj.16774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2023] [Revised: 04/02/2024] [Accepted: 04/08/2024] [Indexed: 04/25/2024]
Abstract
Uncovering the function of phytopathogen effectors is crucial for understanding mechanisms of pathogen pathogenicity and for improving our ability to protect plants from diseases. An increasing number of effectors have been predicted in various plant pathogens. Functional characterization of these effectors has become a major focus in the study of plant-pathogen interactions. In this study, we designed a novel screening system that combines the TMV (tobacco mosaic virus)-GFP vector and Agrobacterium-mediated transient expression in the model plant Nicotiana benthamiana. This system enables the rapid identification of effectors that interfere with plant immunity. The biological function of these effectors can be easily evaluated by observing the GFP fluorescence signal using a UV lamp within just a few days. To evaluate the TMV-GFP system, we initially tested it with well-described virulence and avirulence type III effectors from the bacterial pathogen Ralstonia solanacearum. After proving the accuracy and efficiency of the TMV-GFP system, we successfully screened a novel virulence effector, RipS1, using this approach. Furthermore, using the TMV-GFP system, we reproduced consistent results with previously known cytoplasmic effectors from a diverse array of pathogens. Additionally, we demonstrated the effectiveness of the TMV-GFP system in identifying apoplastic effectors. The easy operation, time-saving nature, broad effectiveness, and low technical requirements of the TMV-GFP system make it a promising approach for high-throughput screening of effectors with immune interference activity from various pathogens.
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Affiliation(s)
- Peng Cao
- College of Life Sciences, Shaanxi Normal University, Xi'an, 710119, China
| | - Haotian Shi
- College of Life Sciences, Shaanxi Normal University, Xi'an, 710119, China
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, 210095, China
| | - Shuangxi Zhang
- College of Life Sciences, Shaanxi Normal University, Xi'an, 710119, China
| | - Jialan Chen
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, 210095, China
| | - Rongbo Wang
- Fujian Key Laboratory for Monitoring and Integrated Management of Crop Pests, Institute of Plant Protection, Fujian Academy of Agricultural Sciences, Fuzhou, 350003, China
| | - Peiqing Liu
- Fujian Key Laboratory for Monitoring and Integrated Management of Crop Pests, Institute of Plant Protection, Fujian Academy of Agricultural Sciences, Fuzhou, 350003, China
| | - Yingfang Zhu
- State Key Laboratory of Crop Stress Adaptation and Improvement, Key Laboratory of Cotton Biology, School of Life Sciences, Henan University, Kaifeng, 475001, China
| | - Yuyan An
- College of Life Sciences, Shaanxi Normal University, Xi'an, 710119, China
| | - Meixiang Zhang
- College of Life Sciences, Shaanxi Normal University, Xi'an, 710119, China
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2
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Christian N, Perlin MH. Plant-endophyte communication: Scaling from molecular mechanisms to ecological outcomes. Mycologia 2024; 116:227-250. [PMID: 38380970 DOI: 10.1080/00275514.2023.2299658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 12/22/2023] [Indexed: 02/22/2024]
Abstract
Diverse communities of fungal endophytes reside in plant tissues, where they affect and are affected by plant physiology and ecology. For these intimate interactions to form and persist, endophytes and their host plants engage in intricate systems of communication. The conversation between fungal endophytes and plant hosts ultimately dictates endophyte community composition and function and has cascading effects on plant health and plant interactions. In this review, we synthesize our current knowledge on the mechanisms and strategies of communication used by endophytic fungi and their plant hosts. We discuss the molecular mechanisms of communication that lead to organ specificity of endophytic communities and distinguish endophytes, pathogens, and saprotrophs. We conclude by offering emerging perspectives on the relevance of plant-endophyte communication to microbial community ecology and plant health and function.
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Affiliation(s)
- Natalie Christian
- Department of Biology, University of Louisville, Louisville, Kentucky 40292
| | - Michael H Perlin
- Department of Biology, University of Louisville, Louisville, Kentucky 40292
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Li P, Li W, Zhou X, Situ J, Xie L, Xi P, Yang B, Kong G, Jiang Z. Peronophythora litchii RXLR effector P. litchii avirulence homolog 202 destabilizes a host ethylene biosynthesis enzyme. PLANT PHYSIOLOGY 2023; 193:756-774. [PMID: 37232407 DOI: 10.1093/plphys/kiad311] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 02/24/2023] [Indexed: 05/27/2023]
Abstract
Oomycete pathogens can secrete hundreds of effectors into plant cells to interfere with the plant immune system during infection. Here, we identified a Arg-X-Leu-Arg (RXLR) effector protein from the most destructive pathogen of litchi (Litchi chinensis Sonn.), Peronophythora litchii, and named it P. litchii avirulence homolog 202 (PlAvh202). PlAvh202 could suppress cell death triggered by infestin 1 or avirulence protein 3a/resistance protein 3a in Nicotiana benthamiana and was essential for P. litchii virulence. In addition, PlAvh202 suppressed plant immune responses and promoted the susceptibility of N. benthamiana to Phytophthora capsici. Further research revealed that PlAvh202 could suppress ethylene (ET) production by targeting and destabilizing plant S-adenosyl-L-methionine synthetase (SAMS), a key enzyme in the ET biosynthesis pathway, in a 26S proteasome-dependent manner without affecting its expression. Transient expression of LcSAMS3 induced ET production and enhanced plant resistance, whereas inhibition of ET biosynthesis promoted P. litchii infection, supporting that litchi SAMS (LcSAMS) and ET positively regulate litchi immunity toward P. litchii. Overall, these findings highlight that SAMS can be targeted by the oomycete RXLR effector to manipulate ET-mediated plant immunity.
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Affiliation(s)
- Peng Li
- Guangdong Key Laboratory of Microbial Signals and Disease Control/Department of Plant Pathology, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China
| | - Wen Li
- Guangdong Key Laboratory of Microbial Signals and Disease Control/Department of Plant Pathology, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China
| | - Xiaofan Zhou
- Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou 510642, China
| | - Junjian Situ
- Guangdong Key Laboratory of Microbial Signals and Disease Control/Department of Plant Pathology, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China
| | - Lizhu Xie
- Guangdong Key Laboratory of Microbial Signals and Disease Control/Department of Plant Pathology, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China
| | - Pinggen Xi
- Guangdong Key Laboratory of Microbial Signals and Disease Control/Department of Plant Pathology, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China
| | - Bo Yang
- College of Grassland Science/Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China
| | - Guanghui Kong
- Guangdong Key Laboratory of Microbial Signals and Disease Control/Department of Plant Pathology, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China
| | - Zide Jiang
- Guangdong Key Laboratory of Microbial Signals and Disease Control/Department of Plant Pathology, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China
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Sun X, Fang X, Wang D, Jones DA, Ma L. Transcriptome Analysis of Fusarium–Tomato Interaction Based on an Updated Genome Annotation of Fusarium oxysporum f. sp. lycopersici Identifies Novel Effector Candidates That Suppress or Induce Cell Death in Nicotiana benthamiana. J Fungi (Basel) 2022; 8:jof8070672. [PMID: 35887429 PMCID: PMC9316272 DOI: 10.3390/jof8070672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 06/15/2022] [Accepted: 06/23/2022] [Indexed: 12/10/2022] Open
Abstract
Fusarium oxysporum f. sp. lycopersici (Fol) causes vascular wilt disease in tomato. Upon colonization of the host, Fol secretes many small effector proteins into the xylem sap to facilitate infection. Besides known SIX (secreted in xylem) proteins, the identity of additional effectors that contribute to Fol pathogenicity remains largely unexplored. We performed a deep RNA-sequencing analysis of Fol race 2-infected tomato, used the sequence data to annotate a published genome assembly generated via PacBio SMRT sequencing of the Fol race 2 reference strain Fol4287, and analysed the resulting transcriptome to identify Fol effector candidates among the newly annotated genes. We examined the Fol-infection expression profiles of all 13 SIX genes present in Fol race 2 and identified 27 new candidate effector genes that were likewise significantly upregulated upon Fol infection. Using Agrobacterium-mediated transformation, we tested the ability of 22 of the new candidate effector genes to suppress or induce cell death in leaves of Nicotiana benthamiana. One effector candidate designated Fol-EC19, encoding a secreted guanyl-specific ribonuclease, was found to trigger cell death and two effector candidates designated Fol-EC14 and Fol-EC20, encoding a glucanase and a secreted trypsin, respectively, were identified that can suppress Bax-mediated cell death. Remarkably, Fol-EC14 and Fol-EC20 were also found to suppress I-2/Avr2- and I/Avr1-mediated cell death. Using the yeast secretion trap screening system, we showed that these three biologically-active effector candidates each contain a functional signal peptide for protein secretion. Our findings provide a basis for further understanding the virulence functions of Fol effectors.
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Affiliation(s)
- Xizhe Sun
- State Key Laboratory of North China Crop Improvement and Regulation, Hebei Agricultural University, Baoding 071001, China; (X.S.); (D.W.)
- Division of Plant Science, Research School of Biology, the Australian National University, Canberra 2601, Australia
- Hebei Key Laboratory of Plant Physiology and Molecular Pathology, College of Life Science, Hebei Agricultural University, Baoding 071001, China
| | - Xiangling Fang
- State Key Laboratory of Grassland Agro-Ecosystems, Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture and Rural Affairs, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730020, China;
| | - Dongmei Wang
- State Key Laboratory of North China Crop Improvement and Regulation, Hebei Agricultural University, Baoding 071001, China; (X.S.); (D.W.)
- Hebei Key Laboratory of Plant Physiology and Molecular Pathology, College of Life Science, Hebei Agricultural University, Baoding 071001, China
| | - David A. Jones
- Division of Plant Science, Research School of Biology, the Australian National University, Canberra 2601, Australia
- Correspondence: (D.A.J.); (L.M.)
| | - Lisong Ma
- State Key Laboratory of North China Crop Improvement and Regulation, Hebei Agricultural University, Baoding 071001, China; (X.S.); (D.W.)
- Division of Plant Science, Research School of Biology, the Australian National University, Canberra 2601, Australia
- College of Horticulture, Hebei Agricultural University, Baoding 071001, China
- Correspondence: (D.A.J.); (L.M.)
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The Sporisorium reilianum Effector Vag2 Promotes Head Smut Disease via Suppression of Plant Defense Responses. J Fungi (Basel) 2022; 8:jof8050498. [PMID: 35628753 PMCID: PMC9146561 DOI: 10.3390/jof8050498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 05/09/2022] [Accepted: 05/10/2022] [Indexed: 01/27/2023] Open
Abstract
Genome comparison between the maize pathogens Ustilago maydis and Sporisorium reilianum revealed a large diversity region (19-1) containing nearly 30 effector gene candidates, whose deletion severely hampers virulence of both fungi. Dissection of the S. reilianum gene cluster resulted in the identification of one major contributor to virulence, virulence-associated gene 2 (vag2; sr10050). Quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR) experiments revealed high expression of vag2 during biotrophic growth of S. reilianum. Using the yeast secretion trap assay, we confirmed the existence of a functional signal peptide allowing protein secretion via the conventional secretory pathway. We identified the cytoplasmic maize chorismate mutase ZmCM2 by yeast two-hybrid screening as a possible interaction partner of Vag2. Interaction of the two proteins in planta was confirmed by bimolecular fluorescence complementation. qRT-PCR experiments revealed vag2-dependent downregulation of salicylic acid (SA)-induced genes, which correlated with higher SA levels in plant tissues colonized by Δvag2 deletion strains relative to S. reilianum wildtype strains. Metabolite analysis suggested rewiring of pathogen-induced SA biosynthesis by preferential conversion of the SA precursor chorismate into the aromatic amino acid precursor prephenate by ZmCM2 in the presence of Vag2. Possibly, the binding of Vag2 to ZmCM2 inhibits the back reaction of the ZmCM2-catalyzed interconversion of chorismate and prephenate, thus contributing to fungal virulence by lowering the plant SA-induced defenses.
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Zhang B, Zhang N, Zhang Q, Xu Q, Zhong T, Zhang K, Xu M. Transcriptome Profiles of Sporisorium reilianum during the Early Infection of Resistant and Susceptible Maize Isogenic Lines. J Fungi (Basel) 2021; 7:jof7020150. [PMID: 33669631 PMCID: PMC7922634 DOI: 10.3390/jof7020150] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 02/10/2021] [Accepted: 02/16/2021] [Indexed: 12/24/2022] Open
Abstract
The biotrophic fungus Sporisorium reilianum causes destructive head smut disease in maize (Zea mays L.). To explore the pathogenicity arsenal of this fungus, we tracked its transcriptome changes during infection of the maize seedling mesocotyls of two near-isogenic lines, HZ4 and HZ4R, differing solely in the disease resistance gene ZmWAK. Parasitic growth of S. reilianum resulted in thousands of differentially expressed genes (DEGs) compared with growth in axenic culture. The protein synthesis and energy metabolism of S. reilianum were predominantly enriched with down-regulated DEGs, consistent with the arrested hyphal growth observed following colonization. Nutrition-related metabolic processes were enriched with both up- and down-regulated DEGs, which, together with activated transmembrane transport, reflected a potential transition in nutrition uptake of S. reilianum once it invaded maize. Notably, genes encoding secreted proteins of S. reilianum were mostly up-regulated during biotrophy. ZmWAK-mediated resistance to head smut disease reduced the number of DEGs of S. reilianum, particularly those related to the secretome. These observations deepen our understanding of the mechanisms underlying S. reilianum pathogenicity and ZmWAK-induced innate immunity.
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Affiliation(s)
- Boqi Zhang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Agronomy and Biotechnology, National Maize Improvement Center, Center for Crop Functional Genomics and Molecular Breeding, China Agricultural University, 2 West Yuanmingyuan Road, Beijing 100193, China; (B.Z.); (N.Z.); (Q.Z.); (Q.X.); (T.Z.); (K.Z.)
| | - Nan Zhang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Agronomy and Biotechnology, National Maize Improvement Center, Center for Crop Functional Genomics and Molecular Breeding, China Agricultural University, 2 West Yuanmingyuan Road, Beijing 100193, China; (B.Z.); (N.Z.); (Q.Z.); (Q.X.); (T.Z.); (K.Z.)
- Crops Research Institute, Guangdong Academy of Agricultural Sciences, Jinying 2 West Road, Tianhe District, Guangzhou 510640, China
| | - Qianqian Zhang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Agronomy and Biotechnology, National Maize Improvement Center, Center for Crop Functional Genomics and Molecular Breeding, China Agricultural University, 2 West Yuanmingyuan Road, Beijing 100193, China; (B.Z.); (N.Z.); (Q.Z.); (Q.X.); (T.Z.); (K.Z.)
| | - Qianya Xu
- State Key Laboratory of Plant Physiology and Biochemistry, College of Agronomy and Biotechnology, National Maize Improvement Center, Center for Crop Functional Genomics and Molecular Breeding, China Agricultural University, 2 West Yuanmingyuan Road, Beijing 100193, China; (B.Z.); (N.Z.); (Q.Z.); (Q.X.); (T.Z.); (K.Z.)
| | - Tao Zhong
- State Key Laboratory of Plant Physiology and Biochemistry, College of Agronomy and Biotechnology, National Maize Improvement Center, Center for Crop Functional Genomics and Molecular Breeding, China Agricultural University, 2 West Yuanmingyuan Road, Beijing 100193, China; (B.Z.); (N.Z.); (Q.Z.); (Q.X.); (T.Z.); (K.Z.)
| | - Kaiyue Zhang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Agronomy and Biotechnology, National Maize Improvement Center, Center for Crop Functional Genomics and Molecular Breeding, China Agricultural University, 2 West Yuanmingyuan Road, Beijing 100193, China; (B.Z.); (N.Z.); (Q.Z.); (Q.X.); (T.Z.); (K.Z.)
| | - Mingliang Xu
- State Key Laboratory of Plant Physiology and Biochemistry, College of Agronomy and Biotechnology, National Maize Improvement Center, Center for Crop Functional Genomics and Molecular Breeding, China Agricultural University, 2 West Yuanmingyuan Road, Beijing 100193, China; (B.Z.); (N.Z.); (Q.Z.); (Q.X.); (T.Z.); (K.Z.)
- Correspondence: ; Tel.: +86-010-6273-3166
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Montenegro Alonso AP, Ali S, Song X, Linning R, Bakkeren G. UhAVR1, an HR-Triggering Avirulence Effector of Ustilago hordei, Is Secreted via the ER-Golgi Pathway, Localizes to the Cytosol of Barley Cells during in Planta-Expression, and Contributes to Virulence Early in Infection. J Fungi (Basel) 2020; 6:E178. [PMID: 32961976 PMCID: PMC7559581 DOI: 10.3390/jof6030178] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Revised: 09/15/2020] [Accepted: 09/15/2020] [Indexed: 12/19/2022] Open
Abstract
The basidiomycete Ustilago hordei causes covered smut disease of barley and oats. Virulence effectors promoting infection and supporting pathogen lifestyle have been described for this fungus. Genetically, six avirulence genes are known and one codes for UhAVR1, the only proven avirulence effector identified in smuts to date that triggers complete immunity in barley cultivars carrying resistance gene Ruh1. A prerequisite for resistance breeding is understanding the host targets and molecular function of UhAVR1. Analysis of this effector upon natural infection of barley coleoptiles using teliospores showed that UhAVR1 is expressed during the early stages of fungal infection where it leads to HR triggering in resistant cultivars or performs its virulence function in susceptible cultivars. Fungal secretion of UhAVR1 is directed by its signal peptide and occurs via the BrefeldinA-sensitive ER-Golgi pathway in cell culture away from its host. Transient in planta expression of UhAVR1 in barley and a nonhost, Nicotiana benthamiana, supports a cytosolic localization. Delivery of UhAVR1 via foxtail mosaic virus or Pseudomonas species in both barley and N. benthamiana reveals a role in suppressing components common to both plant systems of Effector- and Pattern-Triggered Immunity, including necrosis triggered by Agrobacterium-delivered cell death inducers.
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Affiliation(s)
- Ana Priscilla Montenegro Alonso
- Department of Botany, University of British Columbia, Vancouver, BC V6T 1Z4, Canada;
- Agriculture and Agri-Food Canada, Summerland Research and Development Centre, Summerland, BC V0H 1Z0, Canada;
| | - Shawkat Ali
- Agriculture and Agri-Food Canada, Kentville Research and Development Centre, Kentville, NS B4N 1J5, Canada;
| | - Xiao Song
- Sandstone Pharmacies Glenmore Landing Calgary-Compounding, 167D, 1600–90 Ave SW Calgary, AB T2V 5A8, Canada;
| | - Rob Linning
- Agriculture and Agri-Food Canada, Summerland Research and Development Centre, Summerland, BC V0H 1Z0, Canada;
| | - Guus Bakkeren
- Agriculture and Agri-Food Canada, Summerland Research and Development Centre, Summerland, BC V0H 1Z0, Canada;
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