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He H, Xu T, Cao F, Xu Y, Dai T, Liu T. PcAvh87, a virulence essential RxLR effector of Phytophthora cinnamomi suppresses host defense and induces cell death in plant nucleus. Microbiol Res 2024; 286:127789. [PMID: 38870619 DOI: 10.1016/j.micres.2024.127789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2024] [Revised: 05/21/2024] [Accepted: 05/27/2024] [Indexed: 06/15/2024]
Abstract
Plants have developed intricate immune mechanisms to impede Phytophthora colonization. In response, Phytophthora secretes RxLR effector proteins that disrupt plant defense and promote infection. The specific molecular interactions through which Phytophthora RxLR effectors undermine plant immunity, however, remain inadequately defined. In this study, we delineate the role of the nuclear-localized RxLR effector PcAvh87, which is pivotal for the full virulence of Phytophthora cinnamomi. Gene expression analysis indicates that PcAvh87 expression is significantly upregulated during the initial infection stages, interacting with the immune responses triggered by the elicitin protein INF1 and pro-apoptotic protein BAX. Utilizing PEG/CaCl2-mediated protoplast transformation and CRISPR/Cas9-mediated gene editing, we generated PcAvh87 knockout mutants, which demonstrated compromised hyphal growth, sporangium development, and zoospore release, along with a marked reduction in pathogenicity. This underscores PcAvh87's crucial role as a virulence determinant. Notably, PcAvh87, conserved across the Phytophthora genus, was found to modulate the activity of plant immune protein 113, thereby attenuating plant immune responses. This implies that the PcAvh87-mediated regulatory mechanism could be a common strategy in Phytophthora species to manipulate plant immunity. Our findings highlight the multifaceted roles of PcAvh87 in promoting P. cinnamomi infection, including its involvement in sporangia production, mycelial growth, and the targeting of plant immune proteins to enhance pathogen virulence.
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Affiliation(s)
- Haibin He
- Co-Innovation Center for the Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, Jiangsu, China
| | - Tingyan Xu
- Co-Innovation Center for the Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, Jiangsu, China
| | - Fuliang Cao
- Co-Innovation Center for the Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, Jiangsu, China
| | - Yue Xu
- Co-Innovation Center for the Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, Jiangsu, China
| | - Tingting Dai
- Co-Innovation Center for the Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, Jiangsu, China.
| | - Tingli Liu
- School of Food Science, Nanjing Xiaozhuang University, 3601 Hongjin Avenue, Nanjing 211171, China.
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2
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Fu Q, Yang J, Zhang K, Yin K, Xiang G, Yin X, Liu G, Xu Y. Plasmopara viticola effector PvCRN11 induces disease resistance to downy mildew in grapevine. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2024; 117:873-891. [PMID: 37950600 DOI: 10.1111/tpj.16534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 10/09/2023] [Accepted: 10/26/2023] [Indexed: 11/12/2023]
Abstract
The downy mildew of grapevine (Vitis vinifera L.) is caused by Plasmopara viticola and is a major production problem in most grape-growing regions. The vast majority of effectors act as virulence factors and sabotage plant immunity. Here, we describe in detail one of the putative P. viticola Crinkler (CRN) effector genes, PvCRN11, which is highly transcribed during the infection stages in the downy mildew-susceptible grapevine V. vinifera cv. 'Pinot Noir' and V. vinifera cv. 'Thompson Seedless'. Cell death-inducing activity analyses reveal that PvCRN11 was able to induce spot cell death in the leaves of Nicotiana benthamiana but did not induce cell death in the leaves of the downy mildew-resistant V. riparia accession 'Beaumont' or of the downy mildew-susceptible 'Thompson Seedless'. Unexpectedly, stable expression of PvCRN11 inhibited the colonization of P. viticola in grapevine and Phytophthora capsici in Arabidopsis. Both transgenic grapevine and Arabidopsis constitutively expressing PvCRN11 promoted plant immunity. PvCRN11 is localized in the nucleus and cytoplasm, whereas PvCRN11-induced plant immunity is nucleus-independent. The purified protein PvCRN11Opt initiated significant plant immunity extracellularly, leading to enhanced accumulations of reactive oxygen species, activation of MAPK and up-regulation of the defense-related genes PR1 and PR2. Furthermore, PvCRN11Opt induces BAK1-dependent immunity in the apoplast, whereas PvCRN11 overexpression in intracellular induces BAK1-independent immunity. In conclusion, the PvCRN11 protein triggers resistance against P. viticola in grapevine, suggesting a potential for the use of PvCRN11 in grape production as a protectant against downy mildew.
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Affiliation(s)
- Qingqing Fu
- State Key Laboratory of Crop Stress Biology in Arid Areas, Northwest A&F University, Yangling, Shaanxi, P.R. China
- College of Horticulture, Northwest A&F University, Yangling, Shaanxi, P.R. China
- Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Yangling, Shaanxi, P.R. China
| | - Jing Yang
- State Key Laboratory of Crop Stress Biology in Arid Areas, Northwest A&F University, Yangling, Shaanxi, P.R. China
- College of Horticulture, Northwest A&F University, Yangling, Shaanxi, P.R. China
- Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Yangling, Shaanxi, P.R. China
| | - Kangzhuang Zhang
- State Key Laboratory of Crop Stress Biology in Arid Areas, Northwest A&F University, Yangling, Shaanxi, P.R. China
- College of Horticulture, Northwest A&F University, Yangling, Shaanxi, P.R. China
- Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Yangling, Shaanxi, P.R. China
| | - Kaixin Yin
- State Key Laboratory of Crop Stress Biology in Arid Areas, Northwest A&F University, Yangling, Shaanxi, P.R. China
- College of Horticulture, Northwest A&F University, Yangling, Shaanxi, P.R. China
- Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Yangling, Shaanxi, P.R. China
| | - Gaoqing Xiang
- State Key Laboratory of Crop Stress Biology in Arid Areas, Northwest A&F University, Yangling, Shaanxi, P.R. China
- College of Horticulture, Northwest A&F University, Yangling, Shaanxi, P.R. China
- Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Yangling, Shaanxi, P.R. China
| | - Xiao Yin
- State Key Laboratory of Crop Stress Biology in Arid Areas, Northwest A&F University, Yangling, Shaanxi, P.R. China
- College of Horticulture, Northwest A&F University, Yangling, Shaanxi, P.R. China
- Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Yangling, Shaanxi, P.R. China
| | - Guotian Liu
- State Key Laboratory of Crop Stress Biology in Arid Areas, Northwest A&F University, Yangling, Shaanxi, P.R. China
- College of Horticulture, Northwest A&F University, Yangling, Shaanxi, P.R. China
- Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Yangling, Shaanxi, P.R. China
| | - Yan Xu
- State Key Laboratory of Crop Stress Biology in Arid Areas, Northwest A&F University, Yangling, Shaanxi, P.R. China
- College of Horticulture, Northwest A&F University, Yangling, Shaanxi, P.R. China
- Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Yangling, Shaanxi, P.R. China
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Ji L, Yang X, Qi F. Distinct Responses to Pathogenic and Symbionic Microorganisms: The Role of Plant Immunity. Int J Mol Sci 2022; 23:ijms231810427. [PMID: 36142339 PMCID: PMC9499406 DOI: 10.3390/ijms231810427] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 09/06/2022] [Accepted: 09/07/2022] [Indexed: 12/03/2022] Open
Abstract
Plants must balance both beneficial (symbiotic) and pathogenic challenges from microorganisms, the former benefitting the plant and agriculture and the latter causing disease and economic harm. Plant innate immunity describes a highly conserved set of defense mechanisms that play pivotal roles in sensing immunogenic signals associated with both symbiotic and pathogenic microbes and subsequent downstream activation of signaling effector networks that protect the plant. An intriguing question is how the innate immune system distinguishes “friends” from “foes”. Here, we summarize recent advances in our understanding of the role and spectrum of innate immunity in recognizing and responding to different microbes. In addition, we also review some of the strategies used by microbes to manipulate plant signaling pathways and thus evade immunity, with emphasis on the use of effector proteins and micro-RNAs (miRNAs). Furthermore, we discuss potential questions that need addressing to advance the field of plant–microbe interactions.
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Comparative genomic analysis reveals cellulase plays an important role in the pathogenicity of Setosphaeria turcica f. sp. zeae. Fungal Biol 2022. [DOI: 10.1016/j.funbio.2022.05.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Short Linear Motifs (SLiMs) in “Core” RxLR Effectors of
Phytophthora parasitica
var.
nicotianae
: a Case of PpRxLR1 Effector. Microbiol Spectr 2022; 10:e0177421. [PMID: 35404090 PMCID: PMC9045269 DOI: 10.1128/spectrum.01774-21] [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] [Indexed: 11/26/2022] Open
Abstract
Oomycetes of the genus Phytophthora encompass several of the most successful plant pathogens described to date. The success of infection by Phytophthora species is attributed to the pathogens’ ability to secrete effector proteins that alter the host’s physiological processes. Structural analyses of effector proteins mainly from bacterial and viral pathogens have revealed the presence of intrinsically disordered regions that host short linear motifs (SLiMs). These motifs play important biological roles by facilitating protein-protein interactions as well as protein translocation. Nonetheless, SLiMs in Phytophthora species RxLR effectors have not been investigated previously and their roles remain unknown. Using a bioinformatics pipeline, we identified 333 candidate RxLR effectors in the strain INRA 310 of Phytophthora parasitica. Of these, 71 (21%) were also found to be present in 10 other genomes of P. parasitica, and hence, these were designated core RxLR effectors (CREs). Within the CRE sequences, the N terminus exhibited enrichment in intrinsically disordered regions compared to the C terminus, suggesting a potential role of disorder in effector translocation. Although the disorder content was reduced in the C-terminal regions, it is important to mention that most SLiMs were in this terminus. PpRxLR1 is one of the 71 CREs identified in this study, and its genes encode a 6-amino acid (aa)-long SLiM at the C terminus. We showed that PpRxLR1 interacts with several host proteins that are implicated in defense. Structural analysis of this effector using homology modeling revealed the presence of potential ligand-binding sites. Among key residues that were predicted to be crucial for ligand binding, L102 and Y106 were of interest since they form part of the 6-aa-long PpRxLR1 SLiM. In silico substitution of these two residues to alanine was predicted to have a significant effect on both the function and the structure of PpRxLR1 effector. Molecular docking simulations revealed possible interactions between PpRxLR1 effector and ubiquitin-associated proteins. The ubiquitin-like SLiM carried in this effector was shown to be a potential mediator of these interactions. Further studies are required to validate and elucidate the underlying molecular mechanism of action. IMPORTANCE The continuous gain and loss of RxLR effectors makes the control of Phytophthora spp. difficult. Therefore, in this study, we endeavored to identify RxLR effectors that are highly conserved among species, also known as “core” RxLR effectors (CREs). We reason that these highly conserved effectors target conserved proteins or processes; thus, they can be harnessed in breeding for durable resistance in plants. To further understand the mechanisms of action of CREs, structural dissection of these proteins is crucial. Intrinsically disordered regions (IDRs) that do not adopt a fixed, three-dimensional fold carry short linear motifs (SLiMs) that mediate biological functions of proteins. The presence and potential role of these SLiMs in CREs of Phytophthora spp. have been overlooked. To our knowledge, we have effectively identified CREs as well as SLiMs with the potential of promoting effector virulence. Together, this work has advanced our comprehension of Phytophthora RxLR effector function and may facilitate the development of innovative and effective control strategies.
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An FYVE-Domain-Containing Protein, PsFP1, Is Involved in Vegetative Growth, Oxidative Stress Response and Virulence of Phytophthora sojae. Int J Mol Sci 2021; 22:ijms22126601. [PMID: 34202990 PMCID: PMC8233823 DOI: 10.3390/ijms22126601] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 06/16/2021] [Accepted: 06/18/2021] [Indexed: 11/18/2022] Open
Abstract
Proteins that contain the FYVE zinc-finger domain are recruited to PtdIns3P-containing membranes, participating in numerous biological processes such as membrane trafficking, cytoskeletal regulation, and receptor signaling. However, the genome-wide distribution, evolution, and biological functions of FYVE-containing proteins are rarely reported for oomycetes. By genome mining of Phytophthora sojae, two proteins (PsFP1 and PsFP2) with a combination of the FYVE domain and the PX domain (a major phosphoinositide binding module) were found. To clarify the functions of PsFP1 and PsFP2, the CRISPR/Cas9-mediated gene replacement system was used to knock out the two genes respectively. Only heterozygous deletion mutants of PsFP1 were recovered, and the expression level of PsFP1 in the heterozygous knockout transformants was significantly down-regulated. These PsFP1 mutants showed a decrease in mycelial growth and pathogenicity and were more sensitive to hydrogen peroxide. These phenotypes were recovered to the level of wild-type by overexpression PsFP1 gene in the PsFP1 heterozygous knockout transformant. In contrast, deletion of PsFP2 had no significant effect on vegetative growth, asexual and sexual reproduction, pathogenicity, or oxidative stress sensitivity. PsFP1 was primarily localized in vesicle-like structures and both the FYVE and PX domains are important for its localization. Overall, our results indicate that PsFP1 plays an important role in the vegetative growth and virulence of P. sojae.
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Han Z, Xiong D, Xu Z, Liu T, Tian C. The Cytospora chrysosperma Virulence Effector CcCAP1 Mainly Localizes to the Plant Nucleus To Suppress Plant Immune Responses. mSphere 2021; 6:e00883-20. [PMID: 33627507 PMCID: PMC8544888 DOI: 10.1128/msphere.00883-20] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 02/01/2021] [Indexed: 01/07/2023] Open
Abstract
Canker disease is caused by the fungus Cytospora chrysosperma and damages a wide range of woody plants, causing major losses to crops and native plants. Plant pathogens secrete virulence-related effectors into host cells during infection to regulate plant immunity and promote colonization. However, the functions of C. chrysosperma effectors remain largely unknown. In this study, we used Agrobacterium tumefaciens-mediated transient expression system in Nicotiana benthamiana and confocal microscopy to investigate the immunoregulation roles and subcellular localization of CcCAP1, a virulence-related effector identified in C. chrysosperma CcCAP1 was significantly induced in the early stages of infection and contains cysteine-rich secretory proteins, antigen 5, and pathogenesis-related 1 proteins (CAP) superfamily domain with four cysteines. CcCAP1 suppressed the programmed cell death triggered by Bcl-2-associated X protein (BAX) and the elicitin infestin1 (INF1) in transient expression assays with Nicotiana benthamiana The CAP superfamily domain was sufficient for its cell death-inhibiting activity and three of the four cysteines in the CAP superfamily domain were indispensable for its activity. Pathogen challenge assays in N. benthamiana demonstrated that transient expression of CcCAP1 promoted Botrytis cinerea infection and restricted reactive oxygen species accumulation, callose deposition, and defense-related gene expression. In addition, expression of green fluorescent protein-labeled CcCAP1 in N. benthamiana showed that it localized to both the plant nucleus and the cytoplasm, but the nuclear localization was essential for its full immune inhibiting activity. These results suggest that this virulence-related effector of C. chrysosperma modulates plant immunity and functions mainly via its nuclear localization and the CAP domain.IMPORTANCE The data presented in this study provide a key resource for understanding the biology and molecular basis of necrotrophic pathogen responses to Nicotiana benthamiana resistance utilizing effector proteins, and CcCAP1 may be used in future studies to understand effector-triggered susceptibility processes in the Cytospora chrysosperma-poplar interaction system.
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Affiliation(s)
- Zhu Han
- The Key Laboratory for Silviculture and Conservation of Ministry of Education, College of Forestry, Beijing Forestry University, Beijing, China
| | - Dianguang Xiong
- The Key Laboratory for Silviculture and Conservation of Ministry of Education, College of Forestry, Beijing Forestry University, Beijing, China
| | - Zhiye Xu
- The Key Laboratory for Silviculture and Conservation of Ministry of Education, College of Forestry, Beijing Forestry University, Beijing, China
| | - Tingli Liu
- Provincial Key Laboratory of Agrobiology, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Chengming Tian
- The Key Laboratory for Silviculture and Conservation of Ministry of Education, College of Forestry, Beijing Forestry University, Beijing, China
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8
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Tomczynska I, Stumpe M, Doan TG, Mauch F. A Phytophthora effector protein promotes symplastic cell-to-cell trafficking by physical interaction with plasmodesmata-localised callose synthases. THE NEW PHYTOLOGIST 2020; 227:1467-1478. [PMID: 32396661 DOI: 10.1111/nph.16653] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 04/20/2020] [Indexed: 05/03/2023]
Abstract
Pathogen effectors act as disease promoting factors that target specific host proteins with roles in plant immunity. Here, we investigated the function of the RxLR3 effector of the plant-pathogen Phytophthora brassicae. Arabidopsis plants expressing a FLAG-RxLR3 fusion protein were used for co-immunoprecipitation followed by liquid chromatography-tandem mass spectrometry to identify host targets of RxLR3. Fluorescently labelled fusion proteins were used for analysis of subcellular localisation and function of RxLR3. Three closely related members of the callose synthase family, CalS1, CalS2 and CalS3, were identified as targets of RxLR3. RxLR3 co-localised with the plasmodesmal marker protein PDLP5 (PLASMODESMATA-LOCALISED PROTEIN 5) and with plasmodesmata-associated deposits of the β-1,3-glucan polymer callose. In line with a function as an inhibitor of plasmodesmal callose synthases (CalS) enzymes, callose depositions were reduced and cell-to-cell trafficking was promoted in the presence of RxLR3. Plasmodesmal callose deposition in response to infection was compared with wild-type suppressed in RxLR3-expressing Arabidopsis lines. Our results implied a virulence function of the RxLR3 effector as a positive regulator of plasmodesmata transport and provided evidence for competition between P. brassicae and Arabidopsis for control of cell-to-cell trafficking.
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Affiliation(s)
- Iga Tomczynska
- Department of Biology, University of Fribourg, 1700, Fribourg, Switzerland
| | - Michael Stumpe
- Department of Biology, University of Fribourg, 1700, Fribourg, Switzerland
| | - Tu Giang Doan
- Department of Biology, University of Fribourg, 1700, Fribourg, Switzerland
| | - Felix Mauch
- Department of Biology, University of Fribourg, 1700, Fribourg, Switzerland
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Lu S, Yu J, Ma L, Dou D. Two phosphatidylinositol 3-kinase components are involved in interactions between Nicotiana benthamiana and Phytophthora by regulating pathogen effectors and host cell death. FUNCTIONAL PLANT BIOLOGY : FPB 2020; 47:293-302. [PMID: 32054565 DOI: 10.1071/fp19155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Accepted: 11/05/2019] [Indexed: 06/10/2023]
Abstract
Phosphatidylinositol 3-phosphate (PtdIns(3)P) has been reported to regulate different physiological processes in plants. PtdIns(3)P is synthesised by the phosphatidylinositol 3-kinase (PI3K) complex which includes common subunits of vacuolar protein sorting (VPS)15, VPS30 and VPS34. Here, we characterised the roles of the important genes NbVPS15, -30 and -34 encoding PI3K components during interactions between Nicotiana benthamiana and Phytophthora pathogens. NbVPS15 and NbVPS34 were upregulated during infection, and plants deficient in these two genes displayed higher resistance to two different Phytophthora pathogens. Silencing NbVPS15 and NbVPS34 decreased the content of PtdIns(3)P in plant cells and the stability of three RxLR (containing the characteristic amino-terminal motif of arginine-X-leucine-arginine, X is any amino acid) effectors. Furthermore, NbVPS15, -30 and -34 were essential for autolysosome formation during Phytophthora capsici infection and limiting programmed cell death (PCD) induced by effectors and elicitors. Taken together, these findings suggest that NbVPS15 and NbVPS34 play a critical role in the resistance of N. benthamiana to Phytophthora pathogens by regulating PtdIns(3)P contents and host PCD.
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Affiliation(s)
- Shan Lu
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China; and State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, China; and Corresponding author.
| | - Jia Yu
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Lina Ma
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Daolong Dou
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
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Cui X, Yan Q, Gan S, Xue D, Wang H, Xing H, Zhao J, Guo N. GmWRKY40, a member of the WRKY transcription factor genes identified from Glycine max L., enhanced the resistance to Phytophthora sojae. BMC PLANT BIOLOGY 2019; 19:598. [PMID: 31888478 PMCID: PMC6937711 DOI: 10.1186/s12870-019-2132-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Accepted: 11/12/2019] [Indexed: 05/18/2023]
Abstract
BACKGROUND The WRKY proteins are a superfamily of transcription factors and members play essential roles in the modulation of diverse physiological processes, such as growth, development, senescence and response to biotic and abiotic stresses. However, the biological roles of the majority of the WRKY family members remains poorly understood in soybean relative to the research progress in model plants. RESULTS In this study, we identified and characterized GmWRKY40, which is a group IIc WRKY gene. Transient expression analysis revealed that the GmWRKY40 protein is located in the nucleus of plant cells. Expression of GmWRKY40 was strongly induced in soybean following infection with Phytophthora sojae, or treatment with methyl jasmonate, ethylene, salicylic acid, and abscisic acid. Furthermore, soybean hairy roots silencing GmWRKY40 enhanced susceptibility to P. sojae infection compared with empty vector transgenic roots. Moreover, suppression of GmWRKY40 decreased the accumulation of reactive oxygen species (ROS) and modified the expression of several oxidation-related genes. Yeast two-hybrid experiment combined with RNA-seq analysis showed that GmWRKY40 interacted with 8 JAZ proteins with or without the WRKY domain or zinc-finger domain of GmWRKY40, suggesting there were different interaction patterns among these interacted proteins. CONCLUSIONS Collectively, these results suggests that GmWRKY40 functions as a positive regulator in soybean plants response to P. sojae through modulating hydrogen peroxide accumulation and JA signaling pathway.
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Affiliation(s)
- Xiaoxia Cui
- National Center for Soybean Improvement, Key Laboratory of Biology and Genetics and Breeding for Soybean, Ministry of Agriculture, State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, 210095 China
| | - Qiang Yan
- National Center for Soybean Improvement, Key Laboratory of Biology and Genetics and Breeding for Soybean, Ministry of Agriculture, State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, 210095 China
| | - Shuping Gan
- National Center for Soybean Improvement, Key Laboratory of Biology and Genetics and Breeding for Soybean, Ministry of Agriculture, State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, 210095 China
| | - Dong Xue
- National Center for Soybean Improvement, Key Laboratory of Biology and Genetics and Breeding for Soybean, Ministry of Agriculture, State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, 210095 China
| | - Haitang Wang
- National Center for Soybean Improvement, Key Laboratory of Biology and Genetics and Breeding for Soybean, Ministry of Agriculture, State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, 210095 China
| | - Han Xing
- National Center for Soybean Improvement, Key Laboratory of Biology and Genetics and Breeding for Soybean, Ministry of Agriculture, State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, 210095 China
| | - Jinming Zhao
- National Center for Soybean Improvement, Key Laboratory of Biology and Genetics and Breeding for Soybean, Ministry of Agriculture, State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, 210095 China
| | - Na Guo
- National Center for Soybean Improvement, Key Laboratory of Biology and Genetics and Breeding for Soybean, Ministry of Agriculture, State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, 210095 China
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11
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Zhang P, Jia Y, Shi J, Chen C, Ye W, Wang Y, Ma W, Qiao Y. The WY domain in the Phytophthora effector PSR1 is required for infection and RNA silencing suppression activity. THE NEW PHYTOLOGIST 2019; 223:839-852. [PMID: 30963588 DOI: 10.1111/nph.15836] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Accepted: 03/29/2019] [Indexed: 05/27/2023]
Abstract
Phytophthora pathogens manipulate host innate immunity by secreting numerous RxLR effectors, thereby facilitating pathogen colonization. Predicted single and tandem repeats of WY domains are the most prominent C-terminal motifs conserved across the Phytophthora RxLR superfamily. However, the functions of individual WY domains in effectors remain poorly understood. The Phytophthora sojae effector PSR1 promotes infection by suppressing small RNA biogenesis in plant hosts. We identified one single WY domain following the RxLR motif in PSR1. This domain was required for RNA silencing suppression activity and infection in Nicotiana benthamiana, Arabidopsis and soybean. Mutations of the conserved residues in the WY domain did not affect the subcellular localization of PSR1 but abolished its effect on plant development and resistance to viral and Phytophthora pathogens. This is at least in part due to decreased protein stability of the PSR1 mutants in planta. The identification of the WY domain in PSR1 allows predicts that a family of PSR1-like effectors also possess RNA silencing suppression activity. Mutation of the conserved residues in two members of this family, PpPSR1L from P. parasitica and PcPSR1L from P. capsici, perturbed their biological functions, indicating that the WY domain is critical in Phytophthora PSR1 and PSR1-like effectors.
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Affiliation(s)
- Peng Zhang
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China
- College of Agriculture, Yangtze University, Jingzhou, 434025, China
| | - Yijuan Jia
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Jinxia Shi
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Chen Chen
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China
- College of Agriculture, Yangtze University, Jingzhou, 434025, China
| | - Wenwu Ye
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, 210095, China
| | - Yuanchao Wang
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, 210095, China
| | - Wenbo Ma
- Department of Plant Pathology and Microbiology, University of California, Riverside, CA, 92521, USA
- Center for Plant Cell Biology, University of California, Riverside, CA, 92521, USA
| | - Yongli Qiao
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China
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12
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Shen D, Li Q, Sun P, Zhang M, Dou D. Intrinsic disorder is a common structural characteristic of RxLR effectors in oomycete pathogens. Fungal Biol 2017; 121:911-919. [PMID: 29029698 DOI: 10.1016/j.funbio.2017.07.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Revised: 07/05/2017] [Accepted: 07/21/2017] [Indexed: 01/31/2023]
Abstract
Intrinsic disorder is common in nature and has been studied to play important biological roles in bacterial effectors. However, disorder in oomycete RxLR effectors has not been investigated previously and the roles are unknown. Our results of PONDR VL-XT disorder analysis showed that predicted oomycete RxLR effectors were significantly more disordered than other effectors and secretome. The distribution of disorder content presented preference that RxLR-dEER regions were enriched in disordered residues, suggesting potential role of disorder in effector translocation. In contrast, the disorder content was depleted in the C-terminal regions, especially for W/Y/L motifs. We also found that around 42 % of putative RxLR proteins were predicted to contain at least one α-helix-forming molecular recognition feature (α-MoRF), and most α-MoRFs were located in the C-terminal regions. Furthermore, both of the disorder mutants of PsAvh18 and PcAvh207 lost the cell death-inducing activity, indicating the potential important role of disordered structure in RxLR effector function. Overall, these results demonstrate that intrinsic disorder is a common characteristic of oomycete RxLR proteins, and we postulate that such structure feature may be important for effector translocation or function. This study extends our understanding of RxLR effectors in protein structures, and opens up new directions to explore novel mechanisms of oomycete RxLR effectors.
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Affiliation(s)
- Danyu Shen
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, 210095, China
| | - Qingling Li
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, 210095, China
| | - Peng Sun
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, 210095, China
| | - Meixiang Zhang
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, 210095, China
| | - Daolong Dou
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, 210095, China.
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13
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Xiang J, Li X, Yin L, Liu Y, Zhang Y, Qu J, Lu J. A candidate RxLR effector from Plasmopara viticola can elicit immune responses in Nicotiana benthamiana. BMC PLANT BIOLOGY 2017; 17:75. [PMID: 28410577 PMCID: PMC5391559 DOI: 10.1186/s12870-017-1016-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Accepted: 03/23/2017] [Indexed: 05/08/2023]
Abstract
BACKGROUND Diverse plant pathogens deliver effectors into plant cells to alter host processes. Oomycete pathogen encodes a large number of putative RxLR effectors which are likely to play a role in manipulating plant defense responses. The secretome of Plasmopara viticola (downy mildew of grapevine) contains at least 162 candidate RxLR effectors discovered in our recent studies, but their roles in infection and pathogenicity remain to be determined. Here, we characterize in depth one of the putative RxLR effectors, PvRxLR16, which has been reported to induce cell death in Nicotiana benthamiana in our previous study. RESULTS The nuclear localization, W/Y/L motifs, and a putative N-glycosylation site in C-terminal of PvRxLR16 were essential for cell death-inducing activity. Suppressor of G-two allele of Skp1 (SGT1), heat shock protein 90 (HSP90) and required for Mla12 resistance (RAR1), but not somatic embryogenesis receptor-like kinase (SERK3), were required for the cell death response triggered by PvRxLR16 in N. benthamiana. Some mitogen-activated protein kinases and transcription factors were also involved in the perception of PvRxLR16 by N. benthamiana. PvRxLR16 could also significantly enhance plant resistance to Phytophthora capsici and the nuclear localization was required for this ability. However, some other PvRxLR effectors could suppress defense responses and disease resistance induced by PvRxLR16, suggesting that it may not trigger host cell death or immune responses during physiological infection under natural conditions. CONCLUSION These data demonstrate that PvRxLR16 may be recognized by endogenous proteins in nucleus to trigger immune responses in N. benthamiana, which in turn can be suppressed by other PvRxLR effectors.
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Affiliation(s)
- Jiang Xiang
- The Viticulture and Enology Program, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
- Center for Viticulture and Enology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Xinlong Li
- The Viticulture and Enology Program, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
| | - Ling Yin
- Guangxi Crop Genetic Improvement and Biotechnology Laboratory, Guangxi Academy of Agricultural Sciences, Nanning, China
| | - Yunxiao Liu
- The Viticulture and Enology Program, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
| | - Yali Zhang
- The Viticulture and Enology Program, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
| | - Junjie Qu
- Guangxi Crop Genetic Improvement and Biotechnology Laboratory, Guangxi Academy of Agricultural Sciences, Nanning, China
| | - Jiang Lu
- The Viticulture and Enology Program, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China.
- Center for Viticulture and Enology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, 200240, China.
- Guangxi Crop Genetic Improvement and Biotechnology Laboratory, Guangxi Academy of Agricultural Sciences, Nanning, China.
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14
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Yang B, Wang Q, Jing M, Guo B, Wu J, Wang H, Wang Y, Lin L, Wang Y, Ye W, Dong S, Wang Y. Distinct regions of the Phytophthora essential effector Avh238 determine its function in cell death activation and plant immunity suppression. THE NEW PHYTOLOGIST 2017; 214:361-375. [PMID: 28134441 DOI: 10.1111/nph.14430] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Accepted: 12/09/2016] [Indexed: 05/20/2023]
Abstract
Phytophthora pathogens secrete effectors to manipulate host innate immunity, thus facilitating infection. Among the RXLR effectors highly induced during Phytophthora sojae infection, Avh238 not only contributes to pathogen virulence but also triggers plant cell death. However, the detailed molecular basis of Avh238 functions remains largely unknown. We mapped the regions responsible for Avh238 functions in pathogen virulence and plant cell death induction using a strategy that combines investigation of natural variation and large-scale mutagenesis assays. The correlation between cellular localization and Avh238 functions was also evaluated. We found that the 79th residue (histidine or leucine) of Avh238 determined its cell death-inducing activity, and that the 53 amino acids in its C-terminal region are responsible for promoting Phytophthora infection. Transient expression of Avh238 in Nicotiana benthamiana revealed that nuclear localization is essential for triggering cell death, while Avh238-mediated suppression of INF1-triggered cell death requires cytoplasmic localization. Our results demonstrate that a representative example of an essential Phytophthora RXLR effector can evolve to escape recognition by the host by mutating one nucleotide site, and can also retain plant immunosuppressive activity to enhance pathogen virulence in planta.
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Affiliation(s)
- Bo Yang
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, 210095, China
- Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), Nanjing, 210095, China
| | - Qunqing Wang
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, 210095, China
- Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), Nanjing, 210095, China
- Department of Plant Pathology, Shandong Agricultural University, Taian, 271018, China
| | - Maofeng Jing
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, 210095, China
- Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), Nanjing, 210095, China
| | - Baodian Guo
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, 210095, China
- Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), Nanjing, 210095, China
| | - Jiawei Wu
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, 210095, China
- Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), Nanjing, 210095, China
| | - Haonan Wang
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, 210095, China
- Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), Nanjing, 210095, China
| | - Yang Wang
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, 210095, China
- Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), Nanjing, 210095, China
| | - Long Lin
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, 210095, China
- Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), Nanjing, 210095, China
| | - Yan Wang
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, 210095, China
- Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), Nanjing, 210095, China
| | - Wenwu Ye
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, 210095, China
- Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), Nanjing, 210095, China
| | - Suomeng Dong
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, 210095, China
- Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), Nanjing, 210095, China
| | - Yuanchao Wang
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, 210095, China
- Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), Nanjing, 210095, China
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15
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Buiate EAS, Xavier KV, Moore N, Torres MF, Farman ML, Schardl CL, Vaillancourt LJ. A comparative genomic analysis of putative pathogenicity genes in the host-specific sibling species Colletotrichum graminicola and Colletotrichum sublineola. BMC Genomics 2017; 18:67. [PMID: 28073340 PMCID: PMC5225507 DOI: 10.1186/s12864-016-3457-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Accepted: 12/22/2016] [Indexed: 01/10/2023] Open
Abstract
Background Colletotrichum graminicola and C. sublineola cause anthracnose leaf and stalk diseases of maize and sorghum, respectively. In spite of their close evolutionary relationship, the two species are completely host-specific. Host specificity is often attributed to pathogen virulence factors, including specialized secondary metabolites (SSM), and small-secreted protein (SSP) effectors. Genes relevant to these categories were manually annotated in two co-occurring, contemporaneous strains of C. graminicola and C. sublineola. A comparative genomic and phylogenetic analysis was performed to address the evolutionary relationships among these and other divergent gene families in the two strains. Results Inoculation of maize with C. sublineola, or of sorghum with C. graminicola, resulted in rapid plant cell death at, or just after, the point of penetration. The two fungal genomes were very similar. More than 50% of the assemblies could be directly aligned, and more than 80% of the gene models were syntenous. More than 90% of the predicted proteins had orthologs in both species. Genes lacking orthologs in the other species (non-conserved genes) included many predicted to encode SSM-associated proteins and SSPs. Other common groups of non-conserved proteins included transporters, transcription factors, and CAZymes. Only 32 SSP genes appeared to be specific to C. graminicola, and 21 to C. sublineola. None of the SSM-associated genes were lineage-specific. Two different strains of C. graminicola, and three strains of C. sublineola, differed in no more than 1% percent of gene sequences from one another. Conclusions Efficient non-host recognition of C. sublineola by maize, and of C. graminicola by sorghum, was observed in epidermal cells as a rapid deployment of visible resistance responses and plant cell death. Numerous non-conserved SSP and SSM-associated predicted proteins that could play a role in this non-host recognition were identified. Additional categories of genes that were also highly divergent suggested an important role for co-evolutionary adaptation to specific host environmental factors, in addition to aspects of initial recognition, in host specificity. This work provides a foundation for future functional studies aimed at clarifying the roles of these proteins, and the possibility of manipulating them to improve management of these two economically important diseases. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-3457-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- E A S Buiate
- Department of Plant Pathology, University of Kentucky, 201F Plant Science Building, 1405 Veterans Drive, Lexington, KY, 40546-0312, USA.,Present Address: Monsanto Company Brazil, Uberlândia, Minas Gerais, Brazil
| | - K V Xavier
- Department of Plant Pathology, University of Kentucky, 201F Plant Science Building, 1405 Veterans Drive, Lexington, KY, 40546-0312, USA
| | - N Moore
- Department of Computer Science, University of Kentucky, Davis Marksbury Building, 328 Rose Street, Lexington, KY, 40504-0633, USA
| | - M F Torres
- Department of Plant Pathology, University of Kentucky, 201F Plant Science Building, 1405 Veterans Drive, Lexington, KY, 40546-0312, USA.,Present Address: Functional Genomics Laboratory, Weill Cornell Medicine, Doha, Qatar
| | - M L Farman
- Department of Plant Pathology, University of Kentucky, 201F Plant Science Building, 1405 Veterans Drive, Lexington, KY, 40546-0312, USA
| | - C L Schardl
- Department of Plant Pathology, University of Kentucky, 201F Plant Science Building, 1405 Veterans Drive, Lexington, KY, 40546-0312, USA
| | - L J Vaillancourt
- Department of Plant Pathology, University of Kentucky, 201F Plant Science Building, 1405 Veterans Drive, Lexington, KY, 40546-0312, USA.
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16
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Kong P, Hong C. Soil bacteria as sources of virulence signal providers promoting plant infection by Phytophthora pathogens. Sci Rep 2016; 6:33239. [PMID: 27616267 PMCID: PMC5018965 DOI: 10.1038/srep33239] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2016] [Accepted: 08/22/2016] [Indexed: 11/08/2022] Open
Abstract
Phytophthora species are known as "plant destroyers" capable of initiating single zoospore infection in the presence of a quorum of chemical signals from the same or closely related species of oomycetes. Since the natural oomycete population is too low to reach a quorum necessary to initiate a disease epidemic, creation of the quorum is reliant on alternate sources. Here, we show that a soil bacterial isolate, Bacillus megaterium Sb5, promotes plant infection by Phytophthora species. In the presence of Sb5 exudates, colonization of rhododendron leaf discs by 12 Phytophthora species/isolates was significantly enhanced, single zoospores of P. nicotianae infected annual vinca and P. sojae race 25 successfully attacked a non-host plant, Nicotiana benthamiana as well as resistant soybean cultivars with RPS1a or RPS3a. Sb5 exudates, most notably the fractions larger than 3 kDa, promoted plant infection by improving zoospore swimming, germination and plant attachment. Sb5 exudates also stimulated infection hypha growth and upregulated effector gene expression. These results suggest that environmental bacteria are important sources of virulence signal providers that promote plant infection by Phytophthora species, advancing our understanding of biotic factors in the environmental component of the Phytophthora disease triangle and of communal infection of plant pathogens.
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Affiliation(s)
- Ping Kong
- Hampton Roads Agricultural Research and Extension Center, Virginia Tech, 1444 Diamond Springs Road, Virginia Beach, VA 23455, USA
| | - Chuanxue Hong
- Hampton Roads Agricultural Research and Extension Center, Virginia Tech, 1444 Diamond Springs Road, Virginia Beach, VA 23455, USA
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17
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Matthiesen RL, Abeysekara NS, Ruiz-Rojas JJ, Biyashev RM, Maroof MAS, Robertson AE. A Method for Combining Isolates of Phytophthora sojae to Screen for Novel Sources of Resistance to Phytophthora Stem and Root Rot in Soybean. PLANT DISEASE 2016; 100:1424-1428. [PMID: 30686197 DOI: 10.1094/pdis-08-15-0916-re] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Soybean cultivars with specific single resistance genes (Rps) are grown to reduce yield loss due to Phytophthora stem and root rot caused by the oomycete pathogen Phytophthora sojae. To identify novel Rps loci, soybean lines are often screened several times, each time with an isolate of P. sojae that differs in virulence on various Rps genes. The goal of this study was to determine whether several isolates of P. sojae that differ in virulence on Rps genes could be combined into a single source of inoculum and used to screen soybean lines for novel Rps genes. A set of 14 soybean differential lines, each carrying a specific Rps gene, was inoculated with three isolates of P. sojae, which differed in virulence on 6 to 10 Rps genes, individually or in a 1:1:1 mixture. Inoculum containing the 1:1:1 mixture of isolates was virulent on 13 Rps genes. The mixed-inoculum method was used to screen 1,019 soybean accessions in a blind assay for novel sources of resistance. In all, 17% of Glycine max accessions and 11% of G. soja accessions were resistant (≤30% dead plants), suggesting that these accessions may carry a novel Rps gene or genes. Advantages of combining isolates into a single source of inoculum include reduced cost, ability to screen soybean germplasm with inoculum virulent on all known Rps genes, and ease of identifying novel sources of resistance. This study is a precursor to identifying novel sources of resistance to P. sojae in soybean using RXLR effectors.
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Affiliation(s)
- R L Matthiesen
- Department of Plant Pathology and Microbiology, Iowa State University, Ames 50011
| | - N S Abeysekara
- Department of Plant and Soil Sciences, University of Delaware, Newark 19716
| | - J J Ruiz-Rojas
- Department of Crop and Soil Environmental Sciences, Virginia Tech, Blacksburg 24060
| | - R M Biyashev
- Department of Crop and Soil Environmental Sciences, Virginia Tech, Blacksburg 24060
| | - M A Saghai Maroof
- Department of Crop and Soil Environmental Sciences, Virginia Tech, Blacksburg 24060
| | - A E Robertson
- Department of Plant Pathology and Microbiology, Iowa State University
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18
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Liu X, Sun Y, Kørner CJ, Du X, Vollmer ME, Pajerowska-Mukhtar KM. Bacterial Leaf Infiltration Assay for Fine Characterization of Plant Defense Responses using the Arabidopsis thaliana-Pseudomonas syringae Pathosystem. J Vis Exp 2015:53364. [PMID: 26485301 PMCID: PMC4692633 DOI: 10.3791/53364] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
In the absence of specialized mobile immune cells, plants utilize their localized programmed cell death and Systemic Acquired Resistance to defend themselves against pathogen attack. The contribution of a specific Arabidopsis gene to the overall plant immune response can be specifically and quantitatively assessed by assaying the pathogen growth within the infected tissue. For over three decades, the hemibiotrophic bacterium Pseudomonas syringae pv. maculicola ES4326 (Psm ES4326) has been widely applied as the model pathogen to investigate the molecular mechanisms underlying the Arabidopsis immune response. To deliver pathogens into the leaf tissue, multiple inoculation methods have been established, e.g., syringe infiltration, dip inoculation, spray, vacuum infiltration, and flood inoculation. The following protocol describes an optimized syringe infiltration method to deliver virulent Psm ES4326 into leaves of adult soil-grown Arabidopsis plants and accurately screen for enhanced disease susceptibility (EDS) towards this pathogen. In addition, this protocol can be supplemented with multiple pre-treatments to further dissect specific immune defects within different layers of plant defense, including Salicylic Acid (SA)-Triggered Immunity (STI) and MAMP-Triggered Immunity (MTI).
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Affiliation(s)
- Xiaoyu Liu
- Department of Biology, University of Alabama at Birmingham
| | - Yali Sun
- Department of Biology, University of Alabama at Birmingham
| | | | - Xinran Du
- Department of Biology, University of Alabama at Birmingham
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19
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Jing M, Ma H, Li H, Guo B, Zhang X, Ye W, Wang H, Wang Q, Wang Y. Differential regulation of defense-related proteins in soybean during compatible and incompatible interactions between Phytophthora sojae and soybean by comparative proteomic analysis. PLANT CELL REPORTS 2015; 34:1263-80. [PMID: 25906415 DOI: 10.1007/s00299-015-1786-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Revised: 03/04/2015] [Accepted: 03/30/2015] [Indexed: 06/04/2023]
Abstract
KEY MESSAGE Few proteomic studies have focused on the plant- Phytophthora interactions, our study provides important information regarding the use of proteomic methods for investigation of the basic mechanisms of plant-Phytophthora interactions. Phytophthora sojae is a fast-spreading and devastating pathogen that is responsible for root and stem rot in soybean crops worldwide. To better understand the response of soybean seedlings to the stress of infection by virulent and avirulent pathogens at the proteomic level, proteins extracted from the hypocotyls of soybean reference cultivar Williams 82 infected by P. sojae P6497 (race 2) and P7076 (race 19), respectively, were analyzed by two-dimensional gel electrophoresis. 95 protein spots were differently expressed, with 83 being successfully identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and subjected to further analysis. Based on the majority of the 83 defense-responsive proteins, and defense-related pathway genes supplemented by a quantitative reverse transcription PCR assay, a defense-related network for soybean infected by virulent and avirulent pathogens was proposed. We found reactive oxygen species (ROS) burst, the expression levels of salicylic acid (SA) signal pathway and biosynthesis of isoflavones were significantly up-regulated in the resistant soybean. Our results imply that following the P. sojae infection, ROS and SA signal pathway in soybean play the major roles in defense against P. sojae. This research will facilitate further investigation of the molecular regulatory mechanism of the defense response in soybean following infection by P. sojae.
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Affiliation(s)
- Maofeng Jing
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, 210095, China
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20
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Heard S, Brown NA, Hammond-Kosack K. An Interspecies Comparative Analysis of the Predicted Secretomes of the Necrotrophic Plant Pathogens Sclerotinia sclerotiorum and Botrytis cinerea. PLoS One 2015; 10:e0130534. [PMID: 26107498 PMCID: PMC4480369 DOI: 10.1371/journal.pone.0130534] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Accepted: 05/22/2015] [Indexed: 11/25/2022] Open
Abstract
Phytopathogenic fungi form intimate associations with host plant species and cause disease. To be successful, fungal pathogens communicate with a susceptible host through the secretion of proteinaceous effectors, hydrolytic enzymes and metabolites. Sclerotinia sclerotiorum and Botrytis cinerea are economically important necrotrophic fungal pathogens that cause disease on numerous crop species. Here, a powerful bioinformatics pipeline was used to predict the refined S. sclerotiorum and B. cinerea secretomes, identifying 432 and 499 proteins respectively. Analyses focusing on S. sclerotiorum revealed that 16% of the secretome encoding genes resided in small, sequence heterogeneous, gene clusters that were distributed over 13 of the 16 predicted chromosomes. Functional analyses highlighted the importance of plant cell hydrolysis, oxidation-reduction processes and the redox state to the S. sclerotiorum and B. cinerea secretomes and potentially host infection. Only 8% of the predicted proteins were distinct between the two secretomes. In contrast to S. sclerotiorum, the B. cinerea secretome lacked CFEM- or LysM-containing proteins. The 115 fungal and oomycete genome comparison identified 30 proteins specific to S. sclerotiorum and B. cinerea, plus 11 proteins specific to S. sclerotiorum and 32 proteins specific to B. cinerea. Expressed sequence tag (EST) and proteomic analyses showed that 246 S. sclerotiorum secretome encoding genes had EST support, including 101 which were only expressed in vitro and 49 which were only expressed in planta, whilst 42 predicted proteins were experimentally proven to be secreted. These detailed in silico analyses of two important necrotrophic pathogens will permit informed choices to be made when candidate effector proteins are selected for function analyses in planta.
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Affiliation(s)
- Steph Heard
- Plant Biology and Crop Science, Rothamsted Research, West Common, Harpenden, Hertfordshire, United Kingdom
| | - Neil A. Brown
- Plant Biology and Crop Science, Rothamsted Research, West Common, Harpenden, Hertfordshire, United Kingdom
| | - Kim Hammond-Kosack
- Plant Biology and Crop Science, Rothamsted Research, West Common, Harpenden, Hertfordshire, United Kingdom
- * E-mail:
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21
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Transcriptome analysis of the entomopathogenic oomycete Lagenidium giganteum reveals putative virulence factors. Appl Environ Microbiol 2014; 80:6427-36. [PMID: 25107973 DOI: 10.1128/aem.02060-14] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A combination of 454 pyrosequencing and Sanger sequencing was used to sample and characterize the transcriptome of the entomopathogenic oomycete Lagenidium giganteum. More than 50,000 high-throughput reads were annotated through homology searches. Several selected reads served as seeds for the amplification and sequencing of full-length transcripts. Phylogenetic analyses inferred from full-length cellulose synthase alignments revealed that L giganteum is nested within the peronosporalean galaxy and as such appears to have evolved from a phytopathogenic ancestor. In agreement with the phylogeny reconstructions, full-length L. giganteum oomycete effector orthologs, corresponding to the cellulose-binding elicitor lectin (CBEL), crinkler (CRN), and elicitin proteins, were characterized by domain organizations similar to those of pathogenicity factors of plant-pathogenic oomycetes. Importantly, the L. giganteum effectors provide a basis for detailing the roles of canonical CRN, CBEL, and elicitin proteins in the infectious process of an oomycete known principally as an animal pathogen. Finally, phylogenetic analyses and genome mining identified members of glycoside hydrolase family 5 subfamily 27 (GH5_27) as putative virulence factors active on the host insect cuticle, based in part on the fact that GH5_27 genes are shared by entomopathogenic oomycetes and fungi but are underrepresented in nonentomopathogenic genomes. The genomic resources gathered from the L. giganteum transcriptome analysis strongly suggest that filamentous entomopathogens (oomycetes and fungi) exhibit convergent evolution: they have evolved independently from plant-associated microbes, have retained genes indicative of plant associations, and may share similar cores of virulence factors, such as GH5_27 enzymes, that are absent from the genomes of their plant-pathogenic relatives.
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22
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Sharma R, Mishra B, Runge F, Thines M. Gene loss rather than gene gain is associated with a host jump from monocots to dicots in the Smut Fungus Melanopsichium pennsylvanicum. Genome Biol Evol 2014; 6:2034-49. [PMID: 25062916 PMCID: PMC4159001 DOI: 10.1093/gbe/evu148] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Smut fungi are well-suited to investigate the ecology and evolution of plant pathogens, as they are strictly biotrophic, yet cultivable on media. Here we report the genome sequence of Melanopsichium pennsylvanicum, closely related to Ustilago maydis and other Poaceae-infecting smuts, but parasitic to a dicot plant. To explore the evolutionary patterns resulting from host adaptation after this huge host jump, the genome of Me. pennsylvanicum was sequenced and compared with the genomes of U. maydis, Sporisorium reilianum, and U. hordei. Although all four genomes had a similar completeness in CEGMA (Core Eukaryotic Genes Mapping Approach) analysis, gene absence was highest in Me. pennsylvanicum, and most pronounced in putative secreted proteins, which are often considered as effector candidates. In contrast, the amount of private genes was similar among the species, highlighting that gene loss rather than gene gain is the hallmark of adaptation after the host jump to the dicot host. Our analyses revealed a trend of putative effectors to be next to another putative effector, but the majority of these are not in clusters and thus the focus on pathogenicity clusters might not be appropriate for all smut genomes. Positive selection studies revealed that Me. pennsylvanicum has the highest number and proportion of genes under positive selection. In general, putative effectors showed a higher proportion of positively selected genes than noneffector candidates. The 248 putative secreted effectors found in all four smut genomes might constitute a core set needed for pathogenicity, whereas those 92 that are found in all grass-parasitic smuts but have no ortholog in Me. pennsylvanicum might constitute a set of effectors important for successful colonization of grass hosts.
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Affiliation(s)
- Rahul Sharma
- Biodiversity and Climate Research Centre (BiK-F), Frankfurt am Main, GermanyInstitute of Ecology, Evolution and Diversity, Goethe University, Frankfurt am Main, GermanySenckenberg Gesellschaft für Naturforschung, Frankfurt am Main, GermanyCluster for Integrative Fungal Research (IPF), Frankfurt am Main, Germany
| | - Bagdevi Mishra
- Biodiversity and Climate Research Centre (BiK-F), Frankfurt am Main, GermanyInstitute of Ecology, Evolution and Diversity, Goethe University, Frankfurt am Main, GermanySenckenberg Gesellschaft für Naturforschung, Frankfurt am Main, Germany
| | - Fabian Runge
- Institute of Botany 210, University of Hohenheim, Stuttgart, Germany
| | - Marco Thines
- Biodiversity and Climate Research Centre (BiK-F), Frankfurt am Main, GermanyInstitute of Ecology, Evolution and Diversity, Goethe University, Frankfurt am Main, GermanySenckenberg Gesellschaft für Naturforschung, Frankfurt am Main, GermanyCluster for Integrative Fungal Research (IPF), Frankfurt am Main, Germany
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Krajaejun T, Lerksuthirat T, Garg G, Lowhnoo T, Yingyong W, Khositnithikul R, Tangphatsornruang S, Suriyaphol P, Ranganathan S, Sullivan TD. Transcriptome analysis reveals pathogenicity and evolutionary history of the pathogenic oomycete Pythium insidiosum. Fungal Biol 2014; 118:640-53. [DOI: 10.1016/j.funbio.2014.01.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Revised: 12/03/2013] [Accepted: 01/24/2014] [Indexed: 12/14/2022]
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24
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Baron OL, van West P, Industri B, Ponchet M, Dubreuil G, Gourbal B, Reichhart JM, Coustau C. Parental transfer of the antimicrobial protein LBP/BPI protects Biomphalaria glabrata eggs against oomycete infections. PLoS Pathog 2013; 9:e1003792. [PMID: 24367257 PMCID: PMC3868517 DOI: 10.1371/journal.ppat.1003792] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Accepted: 10/11/2013] [Indexed: 12/20/2022] Open
Abstract
Vertebrate females transfer antibodies via the placenta, colostrum and milk or via the egg yolk to protect their immunologically immature offspring against pathogens. This evolutionarily important transfer of immunity is poorly documented in invertebrates and basic questions remain regarding the nature and extent of parental protection of offspring. In this study, we show that a lipopolysaccharide binding protein/bactericidal permeability increasing protein family member from the invertebrate Biomphalaria glabrata (BgLBP/BPI1) is massively loaded into the eggs of this freshwater snail. Native and recombinant proteins displayed conserved LPS-binding, antibacterial and membrane permeabilizing activities. A broad screening of various pathogens revealed a previously unknown biocidal activity of the protein against pathogenic water molds (oomycetes), which is conserved in human BPI. RNAi-dependent silencing of LBP/BPI in the parent snails resulted in a significant reduction of reproductive success and extensive death of eggs through oomycete infections. This work provides the first functional evidence that a LBP/BPI is involved in the parental immune protection of invertebrate offspring and reveals a novel and conserved biocidal activity for LBP/BPI family members. Vertebrate immune systems not only protect adult organisms against infections but also increase survival of offspring through parental transfer of innate and adaptive immune factors via the placenta, colostrum and milk or via the egg yolk. This maternal transfer of immunity is critical for species survival as embryos and neonates are immunologically immature and unable to fight off infections at early life stages. Parental immune protection is poorly documented in invertebrates and how the estimated 1.3 million of invertebrate species protect their eggs against pathogens remains an intriguing question. Here, we show that a fresh-water snail, Biomphalaria glabrata massively loads its eggs with a lipopolysaccharide binding protein/bactericidal permeability increasing protein (LBP/BPI) displaying expected antibacterial activities. Remarkably, this snail LBP/BPI also displayed a strong biocidal activity against water molds (oomycetes). This yet unsuspected activity is conserved in human BPI. Gene expression knock-down resulted in the reduction of snail reproductive success and massive death of eggs after water mold infections. This work reveals a novel and conserved biocidal activity for LBP/BPI family members and demonstrates that the snail LBP/BPI represents a major fitness-related protein transferred from parents to their clutches and protecting them from widespread and lethal oomycete infections.
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Affiliation(s)
- Olga Lucia Baron
- Sophia Agrobiotech Institute, INRA-CNRS-UNS, Sophia Antipolis, France
- Institut de Biologie Moléculaire et Cellulaire, UPR9022 CNRS, Strasbourg, France
| | - Pieter van West
- Aberdeen Oomycete Laboratory, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen, United Kingdom
| | - Benoit Industri
- Sophia Agrobiotech Institute, INRA-CNRS-UNS, Sophia Antipolis, France
| | - Michel Ponchet
- Sophia Agrobiotech Institute, INRA-CNRS-UNS, Sophia Antipolis, France
| | | | - Benjamin Gourbal
- Ecologie et Evolution des Interactions, UMR 5244 CNRS, Université de Perpignan Via Domitia, Perpignan, France
| | - Jean-Marc Reichhart
- Institut de Biologie Moléculaire et Cellulaire, UPR9022 CNRS, Strasbourg, France
- * E-mail: (JMR); (CC)
| | - Christine Coustau
- Sophia Agrobiotech Institute, INRA-CNRS-UNS, Sophia Antipolis, France
- * E-mail: (JMR); (CC)
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25
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Structural and functional studies of a phosphatidic acid-binding antifungal plant defensin MtDef4: identification of an RGFRRR motif governing fungal cell entry. PLoS One 2013; 8:e82485. [PMID: 24324798 PMCID: PMC3853197 DOI: 10.1371/journal.pone.0082485] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2013] [Accepted: 10/25/2013] [Indexed: 01/27/2023] Open
Abstract
MtDef4 is a 47-amino acid cysteine-rich evolutionary conserved defensin from a model legume Medicago truncatula. It is an apoplast-localized plant defense protein that inhibits the growth of the ascomycetous fungal pathogen Fusarium graminearum in vitro at micromolar concentrations. Little is known about the mechanisms by which MtDef4 mediates its antifungal activity. In this study, we show that MtDef4 rapidly permeabilizes fungal plasma membrane and is internalized by the fungal cells where it accumulates in the cytoplasm. Furthermore, analysis of the structure of MtDef4 reveals the presence of a positively charged γ-core motif composed of β2 and β3 strands connected by a positively charged RGFRRR loop. Replacement of the RGFRRR sequence with AAAARR or RGFRAA abolishes the ability of MtDef4 to enter fungal cells, suggesting that the RGFRRR loop is a translocation signal required for the internalization of the protein. MtDef4 binds to phosphatidic acid (PA), a precursor for the biosynthesis of membrane phospholipids and a signaling lipid known to recruit cytosolic proteins to membranes. Amino acid substitutions in the RGFRRR sequence which abolish the ability of MtDef4 to enter fungal cells also impair its ability to bind PA. These findings suggest that MtDef4 is a novel antifungal plant defensin capable of entering into fungal cells and affecting intracellular targets and that these processes are mediated by the highly conserved cationic RGFRRR loop via its interaction with PA.
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26
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Chen XR, Xing YP, Li YP, Tong YH, Xu JY. RNA-Seq reveals infection-related gene expression changes in Phytophthora capsici. PLoS One 2013; 8:e74588. [PMID: 24019970 PMCID: PMC3760852 DOI: 10.1371/journal.pone.0074588] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Accepted: 08/05/2013] [Indexed: 12/21/2022] Open
Abstract
Phytophthora capsici is a soilborne plant pathogen capable of infecting a wide range of plants, including many solanaceous crops. However, genetic resistance and fungicides often fail to manage P. capsici due to limited knowledge on the molecular biology and basis of P. capsici pathogenicity. To begin to rectify this situation, Illumina RNA-Seq was used to perform massively parallel sequencing of three cDNA samples derived from P. capsici mycelia (MY), zoospores (ZO) and germinating cysts with germ tubes (GC). Over 11 million reads were generated for each cDNA library analyzed. After read mapping to the gene models of P. capsici reference genome, 13,901, 14,633 and 14,695 putative genes were identified from the reads of the MY, ZO and GC libraries, respectively. Comparative analysis between two of samples showed major differences between the expressed gene content of MY, ZO and GC stages. A large number of genes associated with specific stages and pathogenicity were identified, including 98 predicted effector genes. The transcriptional levels of 19 effector genes during the developmental and host infection stages of P. capsici were validated by RT-PCR. Ectopic expression in Nicotiana benthamiana showed that P. capsici RXLR and Crinkler effectors can suppress host cell death triggered by diverse elicitors including P. capsici elicitin and NLP effectors. This study provides a first look at the transcriptome and effector arsenal of P. capsici during the important pre-infection stages.
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Affiliation(s)
- Xiao-Ren Chen
- College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, China
| | - Yu-Ping Xing
- College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, China
| | - Yan-Peng Li
- College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, China
| | - Yun-Hui Tong
- College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, China
| | - Jing-You Xu
- College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, China
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27
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Rodewald J, Trognitz B. Solanum resistance genes against Phytophthora infestans and their corresponding avirulence genes. MOLECULAR PLANT PATHOLOGY 2013; 14:740-57. [PMID: 23710878 PMCID: PMC6638693 DOI: 10.1111/mpp.12036] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Resistance genes against Phytophthora infestans (Rpi genes), the most important potato pathogen, are still highly valued in the breeding of Solanum spp. for enhanced resistance. The Rpi genes hitherto explored are localized most often in clusters, which are similar between the diverse Solanum genomes. Their distribution is not independent of late maturity traits. This review provides a summary of the most recent important revelations on the genomic position and cloning of Rpi genes, and the structure, associations, mode of action and activity spectrum of Rpi and corresponding avirulence (Avr) proteins. Practical implications for research into and application of Rpi genes are deduced and combined with an outlook on approaches to address remaining issues and interesting questions. It is evident that the potential of Rpi genes has not been exploited fully.
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Affiliation(s)
- Jan Rodewald
- Department of Health and Environment, Austrian Institute of Technology, Konrad-Lorenz-Straße 24, 3430, Tulln, Austria.
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28
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Yin W, Dong S, Zhai L, Lin Y, Zheng X, Wang Y. The Phytophthora sojae Avr1d gene encodes an RxLR-dEER effector with presence and absence polymorphisms among pathogen strains. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2013; 26:958-68. [PMID: 23594349 DOI: 10.1094/mpmi-02-13-0035-r] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Soybean root and stem rot is caused by the oomycete pathogen Phytophthora sojae. The interaction between P. sojae and soybean fits the "gene-for-gene" hypothesis. Although more than 10 P. sojae avirulence (Avr) effectors have been genetically identified, nearly half of genetically defined avr genes have been cloned. In a previous bioinformatic and global transcriptional analysis, we identified a P. sojae RxLR effector, Avr1d, which was 125 amino acids in length. Mapping data demonstrated that Avr1d presence or absence in the genome was co-segregated with the Avr1d avirulence phenotype in F2 populations. Transient expression of the Avr1d gene using co-bombardment in soybean isogenic lines revealed that this gene triggered a hypersensitive response (HR) in the presence of Rps1d. Sequencing of Avr1d genes in different P. sojae strains revealed two Avr1d alleles. Although polymorphic, the two Avr1d alleles could trigger Rps1d-mediated HR. P. sojae strains carrying either of the alleles were avirulent on Rps1d soybean lines. Avr1d was upregulated during the germinating cyst and early infection stages. Furthermore, transient expression of Avr1d in Nicotiana benthamiana suppressed BAX-induced cell death and enhanced P. capsici infection. Avr1d also suppressed effector-triggered immunity induction by associating with Avr1b and Rps1b, suggestive of a role in suppressing plant immunity.
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Affiliation(s)
- Weixiao Yin
- Nanjing Agricultural University, Nanjing, China
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29
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Shen D, Liu T, Ye W, Liu L, Liu P, Wu Y, Wang Y, Dou D. Gene duplication and fragment recombination drive functional diversification of a superfamily of cytoplasmic effectors in Phytophthora sojae. PLoS One 2013; 8:e70036. [PMID: 23922898 PMCID: PMC3726527 DOI: 10.1371/journal.pone.0070036] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2013] [Accepted: 06/14/2013] [Indexed: 11/19/2022] Open
Abstract
Phytophthora and other oomycetes secrete a large number of putative host cytoplasmic effectors with conserved FLAK motifs following signal peptides, termed crinkling and necrosis inducing proteins (CRN), or Crinkler. Here, we first investigated the evolutionary patterns and mechanisms of CRN effectors in Phytophthora sojae and compared them to two other Phytophthora species. The genes encoding CRN effectors could be divided into 45 orthologous gene groups (OGG), and most OGGs unequally distributed in the three species, in which each underwent large number of gene gains or losses, indicating that the CRN genes expanded after species evolution in Phytophthora and evolved through pathoadaptation. The 134 expanded genes in P. sojae encoded family proteins including 82 functional genes and expressed at higher levels while the other 68 genes encoding orphan proteins were less expressed and contained 50 pseudogenes. Furthermore, we demonstrated that most expanded genes underwent gene duplication or/and fragment recombination. Three different mechanisms that drove gene duplication or recombination were identified. Finally, the expanded CRN effectors exhibited varying pathogenic functions, including induction of programmed cell death (PCD) and suppression of PCD through PAMP-triggered immunity or/and effector-triggered immunity. Overall, these results suggest that gene duplication and fragment recombination may be two mechanisms that drive the expansion and neofunctionalization of the CRN family in P. sojae, which aids in understanding the roles of CRN effectors within each oomycete pathogen.
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Affiliation(s)
- Danyu Shen
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, China
| | - Tingli Liu
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, China
| | - Wenwu Ye
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, China
| | - Li Liu
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, China
| | - Peihan Liu
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, China
| | - Yuren Wu
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, China
| | - Yuanchao Wang
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, China
| | - Daolong Dou
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, China
- * E-mail:
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30
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Song T, Kale SD, Arredondo FD, Shen D, Su L, Liu L, Wu Y, Wang Y, Dou D, Tyler BM. Two RxLR avirulence genes in Phytophthora sojae determine soybean Rps1k-mediated disease resistance. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2013; 26:711-20. [PMID: 23530601 DOI: 10.1094/mpmi-12-12-0289-r] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Resistance to Phytophthora sojae (Rps) genes have been widely used in soybean against root and stem rot diseases caused by this oomycete. Among 15 known soybean Rps genes, Rps1k has been the most widely used in the past four decades. Here, we show that the products of two distinct but closely linked RxLR effector genes are detected by Rps1k-containing plants, resulting in disease resistance. One of the genes is Avr1b-1, that confers avirulence in the presence of Rps1b. Three lines of evidence, including overexpression and gene silencing of Avr1b-1 in stable P. sojae transformants, as well as transient expression of this gene in soybean, indicated that Avr1b could trigger an Rps1k-mediated defense response. Some isolates of P. sojae that do not express Avr1b are nevertheless unable to infect Rps1k plants. In those isolates, we identified a second RxLR effector gene (designated Avr1k), located 5 kb away from Avr1b-1. Silencing or overexpression of Avr1k in P. sojae stable transformants resulted in the loss or gain, respectively, of the avirulence phenotype in the presence of Rps1k. Only isolates of P. sojae with mutant alleles of both Avr1b-1 and Avr1k could evade perception by the soybean plants carrying Rps1k.
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Affiliation(s)
- Tianqiao Song
- College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
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31
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Chai C, Lin Y, Shen D, Wu Y, Li H, Dou D. Identification and functional characterization of the soybean GmaPPO12 promoter conferring Phytophthora sojae induced expression. PLoS One 2013; 8:e67670. [PMID: 23840763 PMCID: PMC3695865 DOI: 10.1371/journal.pone.0067670] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Accepted: 05/26/2013] [Indexed: 01/13/2023] Open
Abstract
Identification of pathogen-inducible promoters largely lags behind cloning of the genes for disease resistance. Here, we cloned the soybean GmaPPO12 gene and found that it was rapidly and strongly induced by Phytophthorasojae infection. Computational analysis revealed that its promoter contained many known cis-elements, including several defense related transcriptional factor-binding boxes. We showed that the promoter could mediate induction of GUS expression upon infection in both transient expression assays in Nicotianabenthamiana and stable transgenic soybean hairy roots. Importantly, we demonstrated that pathogen-induced expression of the GmaPPO12 promoter was higher than that of the soybean GmaPR1a promoter. A progressive 5' and 3' deletion analysis revealed two fragments that were essential for promoter activity. Thus, the cloned promoter could be used in transgenic plants to enhance resistance to phytophthora pathogens, and the identified fragment could serve as a candidate to produce synthetic pathogen-induced promoters.
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Affiliation(s)
- Chunyue Chai
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, China
- College of Life Science and Technology, Nanyang Normal University, Nanyang, China
| | - Yanling Lin
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, China
| | - Danyu Shen
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, China
| | - Yuren Wu
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, China
| | - Hongjuan Li
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, China
| | - Daolong Dou
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, China
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32
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Sanju S, Thakur A, Siddappa S, Sreevathsa R, Srivastava N, Shukla P, Singh BP. Pathogen virulence of Phytophthora infestans: from gene to functional genomics. PHYSIOLOGY AND MOLECULAR BIOLOGY OF PLANTS : AN INTERNATIONAL JOURNAL OF FUNCTIONAL PLANT BIOLOGY 2013; 19:165-77. [PMID: 24431484 PMCID: PMC3656195 DOI: 10.1007/s12298-012-0157-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The oomycete, Phytophthora infestans, is one of the most important plant pathogens worldwide. Much of the pathogenic success of P. infestans, the potato late blight agent, relies on its ability to generate large amounts of sporangia from mycelia, which release zoospores that encyst and form infection structures. Until recently, little was known about the molecular basis of oomycete pathogenicity by the avirulence molecules that are perceived by host defenses. To understand the molecular mechanisms interplay in the pathogen and host interactions, knowledge of the genome structure was most important, which is available now after genome sequencing. The mechanism of biotrophic interaction between potato and P. infestans could be determined by understanding the effector biology of the pathogen, which is until now poorly understood. The recent availability of oomycete genome will help in understanding of the signal transduction pathways followed by apoplastic and cytoplasmic effectors for translocation into host cell. Finally based on genomics, novel strategies could be developed for effective management of the crop losses due to the late blight disease.
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Affiliation(s)
- Suman Sanju
- />Central potato Research Institute, Shimla, H.P India 171001
| | - Aditi Thakur
- />Central potato Research Institute, Shimla, H.P India 171001
| | | | - Rohini Sreevathsa
- />National Research Centre for Plant Biotechnology, IARI campus, Pusa, New Delhi—12, India
| | - Nidhi Srivastava
- />Department of Biosciences and Biotechnology, Banasthali University (Rajasthan), Tonk, India 304022
| | - Pradeep Shukla
- />Department of Biological Sciences, School of Basic Sciences, SHIATS, Naini, Allahabad, India 211007
| | - B. P. Singh
- />Central potato Research Institute, Shimla, H.P India 171001
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33
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Sun F, Kale SD, Azurmendi HF, Li D, Tyler BM, Capelluto DGS. Structural basis for interactions of the Phytophthora sojae RxLR effector Avh5 with phosphatidylinositol 3-phosphate and for host cell entry. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2013; 26:330-44. [PMID: 23075041 DOI: 10.1094/mpmi-07-12-0184-r] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Oomycetes such as Phytophthora sojae employ effector proteins that enter plant cells to facilitate infection. Entry of some effector proteins is mediated by RxLR motifs in the effectors and phosphoinositides (PIP) resident in the host plasma membrane such as phosphatidylinositol 3-phosphate (PtdIns(3)P). Recent reports differ regarding the regions on RxLR effectors involved in PIP recognition. We have structurally and functionally characterized the P. sojae effector, avirulence homolog-5 (Avh5). Using nuclear magnetic resonance (NMR) spectroscopy, we demonstrate that Avh5 is helical in nature, with a long N-terminal disordered region. NMR titrations of Avh5 with the PtdIns(3)P head group, inositol 1,3-bisphosphate, directly identified the ligand-binding residues. A C-terminal lysine-rich helical region (helix 2) was the principal lipid-binding site, with the N-terminal RxLR (RFLR) motif playing a more minor role. Mutations in the RFLR motif affected PtdIns(3)P binding, while mutations in the basic helix almost abolished it. Mutations in the RFLR motif or in the basic region both significantly reduced protein entry into plant and human cells. Both regions independently mediated cell entry via a PtdIns(3)P-dependent mechanism. Based on these findings, we propose a model where Avh5 interacts with PtdIns(3)P through its C terminus, and by binding of the RFLR motif, which promotes host cell entry.
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Affiliation(s)
- Furong Sun
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, USA
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34
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Qutob D, Patrick Chapman B, Gijzen M. Transgenerational gene silencing causes gain of virulence in a plant pathogen. Nat Commun 2013; 4:1349. [PMID: 23322037 PMCID: PMC3562452 DOI: 10.1038/ncomms2354] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2012] [Accepted: 12/03/2012] [Indexed: 12/22/2022] Open
Abstract
Avirulence (Avr) genes of plant pathogens encode effector proteins that trigger immunity in plants carrying appropriate resistance (R) genes. The Phytophthora sojae Avr3a gene displays allelic variation in messenger RNA transcript levels. P. sojae strains with detectable Avr3a gene transcripts are avirulent on plants carrying the R-gene Rps3a, whereas strains lacking Avr3a mRNA escape detection by Rps3a and are virulent. Here we show non-Mendelian interactions between naturally occurring Avr3a alleles that result in transgenerational gene silencing, and we identify small RNA molecules of 25 nucleotides that are abundant in gene-silenced strains but not in strains with Avr3a mRNA. This example of transgenerational gene silencing is exceptional because it is naturally occurring and results in gain of virulence in a pathogenic organism.
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Affiliation(s)
- Dinah Qutob
- Agriculture and Agri-Food Canada, 1391 Sandford Street, London, Ontario N5V 4T3, Canada
| | - B. Patrick Chapman
- Agriculture and Agri-Food Canada, 1391 Sandford Street, London, Ontario N5V 4T3, Canada
| | - Mark Gijzen
- Agriculture and Agri-Food Canada, 1391 Sandford Street, London, Ontario N5V 4T3, Canada
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35
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Ma L, Cornelissen BJC, Takken FLW. A nuclear localization for Avr2 from Fusarium oxysporum is required to activate the tomato resistance protein I-2. FRONTIERS IN PLANT SCIENCE 2013; 4:94. [PMID: 23596453 PMCID: PMC3622885 DOI: 10.3389/fpls.2013.00094] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Accepted: 03/27/2013] [Indexed: 05/19/2023]
Abstract
Plant pathogens secrete effector proteins to promote host colonization. During infection of tomato xylem vessels, Fusarium oxysporum f. sp. lycopersici (Fol) secretes the Avr2 effector protein. Besides being a virulence factor, Avr2 is recognized intracellularly by the tomato I-2 resistance protein, resulting in the induction of host defenses. Here, we show that AVR2 is highly expressed in root- and xylem-colonizing hyphae three days post inoculation of roots. Co-expression of I-2 with AVR2 deletion constructs using agroinfiltration in Nicotiana benthamiana leaves revealed that, except for the N-terminal 17 amino acids, the entire AVR2 protein is required to trigger I-2-mediated cell death. The truncated Avr2 variants are still able to form homo-dimers, showing that the central region of Avr2 is required for dimerization. Simultaneous production of I-2 and Avr2 chimeras carrying various subcellular localization signals in N. benthamiana leaves revealed that a nuclear localization of Avr2 is required to trigger I-2-dependent cell death. Nuclear exclusion of Avr2 prevented its activation of I-2, suggesting that Avr2 is recognized by I-2 in the nucleus.
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Affiliation(s)
| | | | - Frank L. W. Takken
- *Correspondence: Frank L. W. Takken, Molecular Plant Pathology, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, Netherlands. e-mail:
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Morais do Amaral A, Antoniw J, Rudd JJ, Hammond-Kosack KE. Defining the predicted protein secretome of the fungal wheat leaf pathogen Mycosphaerella graminicola. PLoS One 2012; 7:e49904. [PMID: 23236356 PMCID: PMC3517617 DOI: 10.1371/journal.pone.0049904] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2012] [Accepted: 10/15/2012] [Indexed: 01/16/2023] Open
Abstract
The Dothideomycete fungus Mycosphaerella graminicola is the causal agent of Septoria tritici blotch, a devastating disease of wheat leaves that causes dramatic decreases in yield. Infection involves an initial extended period of symptomless intercellular colonisation prior to the development of visible necrotic disease lesions. Previous functional genomics and gene expression profiling studies have implicated the production of secreted virulence effector proteins as key facilitators of the initial symptomless growth phase. In order to identify additional candidate virulence effectors, we re-analysed and catalogued the predicted protein secretome of M. graminicola isolate IPO323, which is currently regarded as the reference strain for this species. We combined several bioinformatic approaches in order to increase the probability of identifying truly secreted proteins with either a predicted enzymatic function or an as yet unknown function. An initial secretome of 970 proteins was predicted, whilst further stringent selection criteria predicted 492 proteins. Of these, 321 possess some functional annotation, the composition of which may reflect the strictly intercellular growth habit of this pathogen, leaving 171 with no functional annotation. This analysis identified a protein family encoding secreted peroxidases/chloroperoxidases (PF01328) which is expanded within all members of the family Mycosphaerellaceae. Further analyses were done on the non-annotated proteins for size and cysteine content (effector protein hallmarks), and then by studying the distribution of homologues in 17 other sequenced Dothideomycete fungi within an overall total of 91 predicted proteomes from fungal, oomycete and nematode species. This detailed M. graminicola secretome analysis provides the basis for further functional and comparative genomics studies.
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Avrova A, Knogge W. Rhynchosporium commune: a persistent threat to barley cultivation. MOLECULAR PLANT PATHOLOGY 2012; 13:986-97. [PMID: 22738626 PMCID: PMC6638709 DOI: 10.1111/j.1364-3703.2012.00811.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Rhynchosporium commune is a haploid fungus causing scald or leaf blotch on barley, other Hordeum spp. and Bromus diandrus. TAXONOMY Rhynchosporium commune is an anamorphic Ascomycete closely related to the teleomorph Helotiales genera Oculimacula and Pyrenopeziza. DISEASE SYMPTOMS Rhynchosporium commune causes scald-like lesions on leaves, leaf sheaths and ears. Early symptoms are generally pale grey oval lesions. With time, the lesions acquire a dark brown margin with the centre of the lesion remaining pale green or pale brown. Lesions often merge to form large areas around which leaf yellowing is common. Infection frequently occurs in the leaf axil, which can lead to chlorosis and eventual death of the leaf. LIFE CYCLE Rhynchosporium commune is seed borne, but the importance of this phase of the disease is not fully understood. Debris from previous crops and volunteers, infected from the stubble from previous crops, are considered to be the most important sources of the disease. Autumn-sown crops can become infected very soon after sowing. Secondary spread of disease occurs mainly through splash dispersal of conidia from infected leaves. Rainfall at the stem extension growth stage is the major environmental factor in epidemic development. DETECTION AND QUANTIFICATION: Rhynchosporium commune produces unique beak-shaped, one-septate spores both on leaves and in culture. The development of a specific polymerase chain reaction (PCR) and, more recently, quantitative PCR (qPCR) has allowed the identification of asymptomatic infection in seeds and during the growing season. DISEASE CONTROL The main measure for the control of R. commune is the use of fungicides with different modes of action, in combination with the use of resistant cultivars. However, this is constantly under review because of the ability of the pathogen to adapt to host plant resistance and to develop fungicide resistance.
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Affiliation(s)
- Anna Avrova
- Cell and Molecular Sciences, The James Hutton Institute, Invergowrie, Dundee, DD2 5DA, UK.
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Yu X, Tang J, Wang Q, Ye W, Tao K, Duan S, Lu C, Yang X, Dong S, Zheng X, Wang Y. The RxLR effector Avh241 from Phytophthora sojae requires plasma membrane localization to induce plant cell death. THE NEW PHYTOLOGIST 2012; 196:247-260. [PMID: 22816601 DOI: 10.1111/j.1469-8137.2012.04241.x] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
• The Phytophthora sojae genome encodes hundreds of RxLR effectors predicted to manipulate various plant defense responses, but the molecular mechanisms involved are largely unknown. Here we have characterized in detail the P. sojae RxLR effector Avh241. • To determine the function and localization of Avh241, we transiently expressed it on different plants. Silencing of Avh241 in P. sojae, we determined its virulence during infection. Through the assay of promoting infection by Phytophthora capsici to Nicotiana benthamiana, we further confirmed this virulence role. • Avh241 induced cell death in several different plants and localized to the plant plasma membrane. An N-terminal motif within Avh241 was important for membrane localization and cell death-inducing activity. Two mitogen-activated protein kinases, NbMEK2 and NbWIPK, were required for the cell death triggered by Avh241 in N. benthamiana. Avh241 was important for the pathogen's full virulence on soybean. Avh241 could also promote infection by P. capsici and the membrane localization motif was not required to promote infection. • This work suggests that Avh241 interacts with the plant immune system via at least two different mechanisms, one recognized by plants dependent on subcellular localization and one promoting infection independent on membrane localization.
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Affiliation(s)
- Xiaoli Yu
- College of Plant Protection, Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), Nanjing Agricultural University, Nanjing 210095, China
| | - Junli Tang
- College of Plant Protection, Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), Nanjing Agricultural University, Nanjing 210095, China
| | - Qunqing Wang
- College of Plant Protection, Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), Nanjing Agricultural University, Nanjing 210095, China
| | - Wenwu Ye
- College of Plant Protection, Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), Nanjing Agricultural University, Nanjing 210095, China
| | - Kai Tao
- College of Plant Protection, Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), Nanjing Agricultural University, Nanjing 210095, China
| | - Shuyi Duan
- College of Plant Protection, Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), Nanjing Agricultural University, Nanjing 210095, China
| | - Chenchen Lu
- College of Plant Protection, Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), Nanjing Agricultural University, Nanjing 210095, China
| | - Xinyu Yang
- College of Plant Protection, Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), Nanjing Agricultural University, Nanjing 210095, China
| | - Suomeng Dong
- College of Plant Protection, Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), Nanjing Agricultural University, Nanjing 210095, China
| | - Xiaobo Zheng
- College of Plant Protection, Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), Nanjing Agricultural University, Nanjing 210095, China
| | - Yuanchao Wang
- College of Plant Protection, Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), Nanjing Agricultural University, Nanjing 210095, China
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Bozkurt TO, Schornack S, Banfield MJ, Kamoun S. Oomycetes, effectors, and all that jazz. CURRENT OPINION IN PLANT BIOLOGY 2012; 15:483-92. [PMID: 22483402 DOI: 10.1016/j.pbi.2012.03.008] [Citation(s) in RCA: 129] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2012] [Revised: 03/13/2012] [Accepted: 03/13/2012] [Indexed: 05/20/2023]
Abstract
Plant pathogenic oomycetes secrete a diverse repertoire of effector proteins that modulate host innate immunity and enable parasitic infection. Understanding how effectors evolve, translocate and traffic inside host cells, and perturb host processes are major themes in the study of oomycete-plant interactions. The last year has seen important progress in the study of oomycete effectors with, notably, the elucidation of the 3D structures of five RXLR effectors, and novel insights into how cytoplasmic effectors subvert host cells. In this review, we discuss these and other recent advances and highlight the most important open questions in oomycete effector biology.
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Affiliation(s)
- Tolga O Bozkurt
- The Sainsbury Laboratory, Norwich Research Park, Norwich NR4 7UH, United Kingdom
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Gust AA, Willmann R, Desaki Y, Grabherr HM, Nürnberger T. Plant LysM proteins: modules mediating symbiosis and immunity. TRENDS IN PLANT SCIENCE 2012; 17:495-502. [PMID: 22578284 DOI: 10.1016/j.tplants.2012.04.003] [Citation(s) in RCA: 141] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2012] [Revised: 04/05/2012] [Accepted: 04/11/2012] [Indexed: 05/18/2023]
Abstract
Microbial glycans, such as bacterial peptidoglycans, fungal chitin or rhizobacterial Nod factors (NFs), are important signatures for plant immune activation or for the establishment of beneficial symbioses. Plant lysin motif (LysM) domain proteins serve as modules mediating recognition of these different N-acetylglucosamine (GlcNAc)-containing ligands, suggesting that this class of proteins evolved from an ancient sensor for GlcNAc. During early plant evolution, these glycans probably served as immunogenic patterns activating LysM protein receptor-mediated plant immunity and stopping microbial infection. The biochemical potential of plant LysM proteins for sensing microbial GlcNAc-containing glycans has probably since favored the evolution of receptors facilitating microbial infection and symbiosis.
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Affiliation(s)
- Andrea A Gust
- Department of Plant Biochemistry, ZMBP, University of Tübingen, 72076 Tübingen, Germany.
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Fu SF, Tsai TM, Chen YR, Liu CP, Haiso LJ, Syue LH, Yeh HH, Huang HJ. Characterization of the early response of the orchid, Phalaenopsis amabilis, to Erwinia chrysanthemi infection using expression profiling. PHYSIOLOGIA PLANTARUM 2012; 145:406-25. [PMID: 22268629 DOI: 10.1111/j.1399-3054.2012.01582.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Erwinia chrysanthemi is a devastating bacterial pathogen in Phalaenopsis amabilis and causes soft-rotting disease by secretion of cell wall-degrading enzymes. However, the molecular mechanisms underlying the interaction of P. amabilis with E. chrysanthemi remain elusive. In this study, early molecular events of the plant in response to the pathogen attack were investigated. The alteration in reactive oxygen species accumulation and peroxidase activity occurred at the site of infection. Subsequently, a systematic sequencing of expressed sequence tags (ESTs) using suppression subtractive hybridization (SSH) was performed to obtain the first global picture of the assembly of genes involved in the pathogenesis. The majority of the SSH clones showed a high identity with genes coding for proteins that have known roles in redox homeostasis, responses to pathogens and metabolism. A notable number of the SSH clones were those encoding WRKY, MYB and basic leucine zipper transcription factors, indicating the stimulation of intracellular signal transduction. An orchid gene encoding trans-2-enoyl-CoA reductase (ECR) was the most abundant transcripts in the EST library. ECR is an enzyme catalyzing the very long chain fatty acids (VLCFAs) biosynthesis, and the full-length cDNA of the ECR gene (PaECR1) was obtained. Functional analysis of PaECR1 was conducted by virus-induced gene silencing to knock down the gene expression in P. amabilis. The PaECR1-silenced plants were more susceptible to E. chrysanthemi infection, implying potential roles for VLCFAs in the pathogenesis. In summary, the pathogen-responsive gene expression profiles facilitated a more comprehensive view of the molecular events that underlie this economically important plant-pathogen interaction.
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Affiliation(s)
- Shih-Feng Fu
- Department of Biology, National Changhua University of Education, Changhua, Taiwan
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42
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Nunes CC, Dean RA. Host-induced gene silencing: a tool for understanding fungal host interaction and for developing novel disease control strategies. MOLECULAR PLANT PATHOLOGY 2012; 13:519-29. [PMID: 22111693 PMCID: PMC6638818 DOI: 10.1111/j.1364-3703.2011.00766.x] [Citation(s) in RCA: 114] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Recent discoveries regarding small RNAs and the mechanisms of gene silencing are providing new opportunities to explore fungal pathogen-host interactions and potential strategies for novel disease control. Plant pathogenic fungi are a constant and major threat to global food security; they represent the largest group of disease-causing agents on crop plants on the planet. An initial understanding of RNA silencing mechanisms and small RNAs was derived from model fungi. Now, new knowledge with practical implications for RNA silencing is beginning to emerge from the study of plant-fungus interactions. Recent studies have shown that the expression of silencing constructs in plants designed on fungal genes can specifically silence their targets in invading pathogenic fungi, such as Fusarium verticillioides, Blumeria graminis and Puccinia striiformis f.sp. tritici. Here, we highlight the important general aspects of RNA silencing mechanisms and emphasize recent findings from plant pathogenic fungi. Strategies to employ RNA silencing to investigate the basis of fungal pathogenesis are discussed. Finally, we address important aspects for the development of fungal-derived resistance through the expression of silencing constructs in host plants as a powerful strategy to control fungal disease.
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Affiliation(s)
- Cristiano C Nunes
- Department of Plant Pathology, Fungal Genomics Laboratory, Center for Integrated Fungal Research, North Carolina State University, Raleigh, NC 27606, USA
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Brown NA, Antoniw J, Hammond-Kosack KE. The predicted secretome of the plant pathogenic fungus Fusarium graminearum: a refined comparative analysis. PLoS One 2012; 7:e33731. [PMID: 22493673 PMCID: PMC3320895 DOI: 10.1371/journal.pone.0033731] [Citation(s) in RCA: 125] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2011] [Accepted: 02/16/2012] [Indexed: 11/18/2022] Open
Abstract
The fungus Fusarium graminearum forms an intimate association with the host species wheat whilst infecting the floral tissues at anthesis. During the prolonged latent period of infection, extracellular communication between live pathogen and host cells must occur, implying a role for secreted fungal proteins. The wheat cells in contact with fungal hyphae subsequently die and intracellular hyphal colonisation results in the development of visible disease symptoms. Since the original genome annotation analysis was done in 2007, which predicted the secretome using TargetP, the F. graminearum gene call has changed considerably through the combined efforts of the BROAD and MIPS institutes. As a result of the modifications to the genome and the recent findings that suggested a role for secreted proteins in virulence, the F. graminearum secretome was revisited. In the current study, a refined F. graminearum secretome was predicted by combining several bioinformatic approaches. This strategy increased the probability of identifying truly secreted proteins. A secretome of 574 proteins was predicted of which 99% was supported by transcriptional evidence. The function of the annotated and unannotated secreted proteins was explored. The potential role(s) of the annotated proteins including, putative enzymes, phytotoxins and antifungals are discussed. Characterisation of the unannotated proteins included the analysis of Pfam domains and features associated with known fungal effectors, for example, small size, cysteine-rich and containing internal amino acid repeats. A comprehensive comparative genomic analysis involving 57 fungal and oomycete genomes revealed that only a small number of the predicted F. graminearum secreted proteins can be considered to be either species or sequenced strain specific.
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Affiliation(s)
- Neil A Brown
- Centre for Sustainable Pest and Disease Management, Department of Plant Pathology and Microbiology, Rothamsted Research, Harpenden, Hertfordshire, United Kingdom
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Abstract
Many destructive diseases of plants and animals are caused by oomycetes, a group of eukaryotic pathogens important to agricultural, ornamental, and natural ecosystems. Understanding the mechanisms underlying oomycete virulence and the genomic processes by which those mechanisms rapidly evolve is essential to developing effective long-term control measures for oomycete diseases. Several common mechanisms underlying oomycete virulence, including protein toxins and cell-entering effectors, have emerged from comparing oomycetes with different genome characteristics, parasitic lifestyles, and host ranges. Oomycete genomes display a strongly bipartite organization in which conserved housekeeping genes are concentrated in syntenic gene-rich blocks, whereas virulence genes are dispersed into highly dynamic, repeat-rich regions. There is also evidence that key virulence genes have been acquired by horizontal transfer from other eukaryotic and prokaryotic species.
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Affiliation(s)
- Rays H Y Jiang
- The Broad Institute of the Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts 02142, USA.
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Ve T, Williams SJ, Stamp A, Valkov E, Dodds PN, Anderson PA, Kobe B. Crystallization and X-ray diffraction analysis of the C-terminal domain of the flax rust effector protein AvrM. Acta Crystallogr Sect F Struct Biol Cryst Commun 2011; 67:1603-7. [PMID: 22139177 PMCID: PMC3232150 DOI: 10.1107/s1744309111037675] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2011] [Accepted: 09/15/2011] [Indexed: 11/10/2022]
Abstract
The flax rust effector AvrM is a secreted protein of unknown fold that is recognized by the M resistance protein in flax. In order to investigate the structural basis of the AvrM-M interaction and possible virulence-associated functions of AvrM, the C-terminal domains of two different AvrM variants (AvrM-A and avrM) were crystallized. Crystals of native AvrM-A were obtained using pentaerythritol ethoxylate (15/4 EO/OH) as a precipitant and diffracted X-rays to 2.9 Å resolution. Selenomethionine-derivative crystals of similar quality were obtained using PEG 1500 as a precipitant. Both the native and selenomethionine-labelled AvrM-A crystals had symmetry of space group C222(1) with eight molecules in the asymmetric unit. Crystals of avrM had symmetry of space group P2(1)2(1)2(1) and diffracted X-rays to 2.7 Å resolution. Initial AvrM-A phases were calculated using the single-wavelength anomalous dispersion (SAD) method and a partial model was built. Phases for avrM were obtained by molecular replacement using the partial AvrM-A model.
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Affiliation(s)
- Thomas Ve
- School of Chemistry and Molecular Biosciences, Institute for Molecular Bioscience (Division of Chemistry and Structural Biology), University of Queensland, Brisbane, Queensland, Australia.
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Lv C, Masuda T, Yang H, Sun L, Zhao G. High-capacity calcium-binding chitinase III from pomegranate seeds (Punica granatum Linn.) is located in amyloplasts. PLANT SIGNALING & BEHAVIOR 2011; 6:1963-5. [PMID: 22112454 PMCID: PMC3337188 DOI: 10.4161/psb.6.12.18147] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
We have recently identified a new class III chitinase from pomegranate seeds (PSC). Interestingly, this new chitinase naturally binds calcium ions with high capacity and low affinity, suggesting that PSC is a Ca-storage protein. Analysis of the amino acid sequence showed that this enzyme is rich in acidic amino acid residues, especially Asp, which are responsible for calcium binding. Different from other known chitinases, PSC is located in the stroma of amyloplasts in pomegranate seeds. Transmission electron microscopy (TEM) analysis indicated that the embryonic cells of pomegranate seeds are rich in calcium ions, most of which are distributed in the stroma and the starch granule of the amyloplasts, consistent with the above idea that PSC is involved in calcium storage, a newly non-defensive function.
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Affiliation(s)
- Chenyan Lv
- CAU & ACC Joint-Laboratory of Space Food; College of Food Science & Nutritional Engineering; China Agricultural University; Key Laboratory of Functional Dairy; Beijing, China
| | - Taro Masuda
- Laboratory of Food Quality Design and Development; Division of Agronomy and Horticultural Science; Graduate School of Agriculture; Kyoto University; Kyoto, Japan
| | - Haixia Yang
- CAU & ACC Joint-Laboratory of Space Food; College of Food Science & Nutritional Engineering; China Agricultural University; Key Laboratory of Functional Dairy; Beijing, China
| | - Lei Sun
- Center for Biological Imaging; Institute of Biophysics; Chinese Academy of Sciences; Beijing, China
| | - Guanghua Zhao
- CAU & ACC Joint-Laboratory of Space Food; College of Food Science & Nutritional Engineering; China Agricultural University; Key Laboratory of Functional Dairy; Beijing, China
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Gu B, Kale SD, Wang Q, Wang D, Pan Q, Cao H, Meng Y, Kang Z, Tyler BM, Shan W. Rust secreted protein Ps87 is conserved in diverse fungal pathogens and contains a RXLR-like motif sufficient for translocation into plant cells. PLoS One 2011; 6:e27217. [PMID: 22076138 PMCID: PMC3208592 DOI: 10.1371/journal.pone.0027217] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2011] [Accepted: 10/12/2011] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Effector proteins of biotrophic plant pathogenic fungi and oomycetes are delivered into host cells and play important roles in both disease development and disease resistance response. How obligate fungal pathogen effectors enter host cells is poorly understood. The Ps87 gene of Puccinia striiformis encodes a protein that is conserved in diverse fungal pathogens. Ps87 homologs from a clade containing rust fungi are predicted to be secreted. The aim of this study is to test whether Ps87 may act as an effector during Puccinia striiformis infection. METHODOLOGY/PRINCIPAL FINDINGS Yeast signal sequence trap assay showed that the rust protein Ps87 could be secreted from yeast cells, but a homolog from Magnaporthe oryzae that was not predicted to be secreted, could not. Cell re-entry and protein uptake assays showed that a region of Ps87 containing a conserved RXLR-like motif [K/R]RLTG was confirmed to be capable of delivering oomycete effector Avr1b into soybean leaf cells and carrying GFP into soybean root cells. Mutations in the Ps87 motif (KRLTG) abolished the protein translocation ability. CONCLUSIONS/SIGNIFICANCE The results suggest that Ps87 and its secreted homologs could utilize similar protein translocation machinery as those of oomycete and other fungal pathogens. Ps87 did not show direct suppression activity on plant defense responses. These results suggest Ps87 may represent an "emerging effector" that has recently acquired the ability to enter plant cells but has not yet acquired the ability to alter host physiology.
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Affiliation(s)
- Biao Gu
- College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China
- State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, Shaanxi, China
| | - Shiv D. Kale
- Viginia Bioinformatics Institute, Blacksburg, Virginia, United States of America
| | - Qinhu Wang
- College of Life Science, Northwest A&F University, Yangling, Shaanxi, China
- State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, Shaanxi, China
| | - Dinghe Wang
- College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China
- State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, Shaanxi, China
| | - Qiaona Pan
- College of Life Science, Northwest A&F University, Yangling, Shaanxi, China
- State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, Shaanxi, China
| | - Hua Cao
- College of Life Science, Northwest A&F University, Yangling, Shaanxi, China
- State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, Shaanxi, China
| | - Yuling Meng
- College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China
- State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, Shaanxi, China
| | - Zhensheng Kang
- College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China
- State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, Shaanxi, China
| | - Brett M. Tyler
- Viginia Bioinformatics Institute, Blacksburg, Virginia, United States of America
| | - Weixing Shan
- College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China
- State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, Shaanxi, China
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Hacquard S, Petre B, Frey P, Hecker A, Rouhier N, Duplessis S. The poplar-poplar rust interaction: insights from genomics and transcriptomics. J Pathog 2011; 2011:716041. [PMID: 22567338 PMCID: PMC3335510 DOI: 10.4061/2011/716041] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2011] [Accepted: 06/28/2011] [Indexed: 11/28/2022] Open
Abstract
Poplars are extensively cultivated worldwide, and their susceptibility to the leaf rust fungus Melampsora larici-populina leads to considerable damages in plantations. Despite a good knowledge of the poplar rust life cycle, and particularly the epidemics on poplar, the perennial status of the plant host and the obligate biotrophic lifestyle of the rust fungus are bottlenecks for molecular investigations. Following the completion of both M. larici-populina and Populus trichocarpa genome sequences, gene families involved in poplar resistance or in rust fungus virulence were investigated, allowing the identification of key genetic determinants likely controlling the outcome of the interaction. Specific expansions of resistance and defense-related genes in poplar indicate probable innovations in perennial species in relation with host-pathogen interactions. The genome of M. Larici-populina contains a strikingly high number of genes encoding small secreted proteins (SSPs) representing hundreds of candidate effectors. Transcriptome analyses of interacting partners in compatible and incompatible interactions revealed conserved set of genes involved in poplar defense reactions as well as timely regulated expression of SSP transcripts during host tissues colonisation. Ongoing functional studies of selected candidate effectors will be achieved mainly on the basis of recombinant protein purification and subsequent characterisation.
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Affiliation(s)
- Stéphane Hacquard
- Institut National de la Recherche Agronomique (INRA), Nancy Université, Unité Mixte de Recherche 1136, "Interactions Arbres/Micro-organismes," Centre INRA de Nancy, 54280 Champenoux, France
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As-sadi F, Carrere S, Gascuel Q, Hourlier T, Rengel D, Le Paslier MC, Bordat A, Boniface MC, Brunel D, Gouzy J, Godiard L, Vincourt P. Transcriptomic analysis of the interaction between Helianthus annuus and its obligate parasite Plasmopara halstedii shows single nucleotide polymorphisms in CRN sequences. BMC Genomics 2011; 12:498. [PMID: 21988821 PMCID: PMC3204308 DOI: 10.1186/1471-2164-12-498] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2011] [Accepted: 10/11/2011] [Indexed: 11/30/2022] Open
Abstract
Background Downy mildew in sunflowers (Helianthus annuus L.) is caused by the oomycete Plasmopara halstedii (Farl.) Berlese et de Toni. Despite efforts by the international community to breed mildew-resistant varieties, downy mildew remains a major threat to the sunflower crop. Very few genomic, genetic and molecular resources are currently available to study this pathogen. Using a 454 sequencing method, expressed sequence tags (EST) during the interaction between H. annuus and P. halstedii have been generated and a search was performed for sites in putative effectors to show polymorphisms between the different races of P. halstedii. Results A 454 pyrosequencing run of two infected sunflower samples (inbred lines XRQ and PSC8 infected with race 710 of P. halstedii, which exhibit incompatible and compatible interactions, respectively) generated 113,720 and 172,107 useable reads. From these reads, 44,948 contigs and singletons have been produced. A bioinformatic portal, HP, was specifically created for in-depth analysis of these clusters. Using in silico filtering, 405 clusters were defined as being specific to oomycetes, and 172 were defined as non-specific oomycete clusters. A subset of these two categories was checked using PCR amplification, and 86% of the tested clusters were validated. Twenty putative RXLR and CRN effectors were detected using PSI-BLAST. Using corresponding sequences from four races (100, 304, 703 and 710), 22 SNPs were detected, providing new information on pathogen polymorphisms. Conclusions This study identified a large number of genes that are expressed during H. annuus/P. halstedii compatible or incompatible interactions. It also reveals, for the first time, that an infection mechanism exists in P. halstedii similar to that in other oomycetes associated with the presence of putative RXLR and CRN effectors. SNPs discovered in CRN effector sequences were used to determine the genetic distances between the four races of P. halstedii. This work therefore provides valuable tools for further discoveries regarding the H. annuus/P. halstedii pathosystem.
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Affiliation(s)
- Falah As-sadi
- INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441, F-31326 Castanet-Tolosan, France
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Abstract
Fungal and oomycete pathogens cause many destructive diseases of plants and important diseases of humans and other animals. Fungal and oomycete plant pathogens secrete numerous effector proteins that can enter inside host cells to condition susceptibility. Until recently it has been unknown if these effectors enter via pathogen-encoded translocons or via pathogen-independent mechanisms. Here we review recent evidence that many fungal and oomycete effectors enter via receptor-mediated endocytosis, and can do so in the absence of the pathogen. Surprisingly, a large number of these effectors utilize cell surface phosphatidyinositol-3-phosphate (PI-3-P) as a receptor, a molecule previously known only inside cells. Binding of effectors to PI-3-P appears to be mediated by the cell entry motif RXLR in oomycetes, and by diverse RXLR-like variants in fungi. PI-3-P appears to be present on the surface of animal cells also, suggesting that it may mediate entry of effectors of fungal and oomycete animal pathogens, for example, RXLR effectors found in the oomycete fish pathogen, Saprolegnia parasitica. Reagents that can block PI-3-P-mediated entry have been identified, suggesting new therapeutic strategies.
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Affiliation(s)
- Shiv D Kale
- Virginia Bioinformatics Institute, Virginia Tech, Blacksburg, VA 24061-0477, USA
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