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Zhong S, Zhang S, Zheng Y, Zhang Q, Liu F, Wang Z, Liu X. Distinct small RNAs are expressed at different stages of Phytophthora capsici and play important roles in development and pathogenesis. Front Genet 2024; 15:1296533. [PMID: 38919951 PMCID: PMC11196614 DOI: 10.3389/fgene.2024.1296533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Accepted: 05/21/2024] [Indexed: 06/27/2024] Open
Abstract
Small RNAs (sRNAs) are important non-coding RNA regulators that play key roles in the development and pathogenesis of plant pathogens, as well as in other biological processes. However, whether these abundant and varying sRNAs are involved in Phytophthora development or infection remains enigmatic. In this study, sRNA sequencing of 4 asexual stages of Phytophthora capsici (P. capsici), namely, as mycelia (HY), sporangia (SP), zoospores (ZO), cysts (CY), and pepper infected with P. capsici (IN), were performed, followed by sRNA analysis, microRNA (miRNA) identification, and miRNA target prediction. sRNAs were mainly distributed at 25-26 nt in HY, SP, and ZO but distributed at 18-34 nt in CY and IN. 92, 42, 176, 39, and 148 known miRNAs and 15, 19, 54, 13, and 1 novel miRNA were identified in HY, SP, ZO, CY, and IN, respectively. It was found that the expression profiles of known miRNAs vary greatly at different stages and could be divided into 4 categories. Novel miRNAs mostly belong to part I. Gene ontology (GO) analysis of known miRNA-targeting genes showed that they are involved in the catalytic activity pathway, binding function, and other biological processes. Kyoto Encyclopedia of Gene and Genome (KEGG) analysis of novel miRNA-targeting genes showed that they are involved in the lysine degradation pathway. The expression of candidate miRNAs was validated using quantitative reverse transcription-polymerase chain reaction (qRT-PCR), and miRNAs were downregulated in PcDCL1 or PcAGO1 mutants. To further explore the function of the detected miRNAs, the precursor of a novel miRNA, miR91, was knockout by CRISPR-Cas9, the mutants displayed decreased mycelial growth, sporangia production, and zoospore production. It was found that 503142 (Inositol polyphosphate 5-phosphatase and related proteins) can be predicted as a target of miR91, and the interaction between miR91 and 503142 was verified using the tobacco transient expression system. Overall, our results indicate that the diverse and differentially expressed sRNAs are involved in the development and pathogenesis of P. capsici.
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Affiliation(s)
- Shan Zhong
- Sanya Institute of China Agricultural University, Sanya, China
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
| | - Sicong Zhang
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
| | - Yang Zheng
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
| | - Qinghua Zhang
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
| | - Fangmin Liu
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
| | - Zhiwen Wang
- Sanya Institute of China Agricultural University, Sanya, China
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
| | - Xili Liu
- Sanya Institute of China Agricultural University, Sanya, China
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
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2
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Piombo E, Kelbessa BG, Sundararajan P, Whisson SC, Vetukuri RR, Dubey M. RNA silencing proteins and small RNAs in oomycete plant pathogens and biocontrol agents. Front Microbiol 2023; 14:1076522. [PMID: 37032886 PMCID: PMC10080066 DOI: 10.3389/fmicb.2023.1076522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Accepted: 03/03/2023] [Indexed: 04/11/2023] Open
Abstract
Introduction Oomycetes cause several damaging diseases of plants and animals, and some species also act as biocontrol agents on insects, fungi, and other oomycetes. RNA silencing is increasingly being shown to play a role in the pathogenicity of Phytophthora species, either through trans-boundary movement of small RNAs (sRNAs) or through expression regulation of infection promoting effectors. Methods To gain a wider understanding of RNA silencing in oomycete species with more diverse hosts, we mined genome assemblies for Dicer-like (DCL), Argonaute (AGO), and RNA dependent RNA polymerase (RDRP) proteins from Phytophthora plurivora, Ph. cactorum, Ph. colocasiae, Pythium oligandrum, Py. periplocum, and Lagenidium giganteum. Moreover, we sequenced small RNAs from the mycelium stage in each of these species. Results and discussion Each of the species possessed a single DCL protein, but they differed in the number and sequence of AGOs and RDRPs. SRNAs of 21nt, 25nt, and 26nt were prevalent in all oomycetes analyzed, but the relative abundance and 5' base preference of these classes differed markedly between genera. Most sRNAs mapped to transposons and other repeats, signifying that the major role for RNA silencing in oomycetes is to limit the expansion of these elements. We also found that sRNAs may act to regulate the expression of duplicated genes. Other sRNAs mapped to several gene families, and this number was higher in Pythium spp., suggesting a role of RNA silencing in regulating gene expression. Genes for most effector classes were the source of sRNAs of variable size, but some gene families showed a preference for specific classes of sRNAs, such as 25/26 nt sRNAs targeting RxLR effector genes in Phytophthora species. Novel miRNA-like RNAs (milRNAs) were discovered in all species, and two were predicted to target transcripts for RxLR effectors in Ph. plurivora and Ph. cactorum, indicating a putative role in regulating infection. Moreover, milRNAs from the biocontrol Pythium species had matches in the predicted transcriptome of Phytophthora infestans and Botrytis cinerea, and L. giganteum milRNAs matched candidate genes in the mosquito Aedes aegypti. This suggests that trans-boundary RNA silencing may have a role in the biocontrol action of these oomycetes.
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Affiliation(s)
- Edoardo Piombo
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Bekele Gelena Kelbessa
- Department of Plant Breeding, Horticum, Swedish University of Agricultural Sciences, Lomma, Sweden
| | - Poorva Sundararajan
- Department of Plant Breeding, Horticum, Swedish University of Agricultural Sciences, Lomma, Sweden
| | - Stephen C. Whisson
- Department of Cell and Molecular Sciences, The James Hutton Institute, Dundee, United Kingdom
| | - Ramesh Raju Vetukuri
- Department of Plant Breeding, Horticum, Swedish University of Agricultural Sciences, Lomma, Sweden
- *Correspondence: Ramesh Raju Vetukuri, ; Mukesh Dubey,
| | - Mukesh Dubey
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Uppsala, Sweden
- *Correspondence: Ramesh Raju Vetukuri, ; Mukesh Dubey,
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3
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Xu J, Li Y, Jia J, Xiong W, Zhong C, Huang G, Gou X, Meng Y, Shan W. Mutations in PpAGO3 Lead to Enhanced Virulence of Phytophthora parasitica by Activation of 25-26 nt sRNA-Associated Effector Genes. Front Microbiol 2022; 13:856106. [PMID: 35401482 PMCID: PMC8989244 DOI: 10.3389/fmicb.2022.856106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Accepted: 03/03/2022] [Indexed: 12/04/2022] Open
Abstract
Oomycetes represent a unique group of plant pathogens that are destructive to a wide range of crops and natural ecosystems. Phytophthora species possess active small RNA (sRNA) silencing pathways, but little is known about the biological roles of sRNAs and associated factors in pathogenicity. Here we show that an AGO gene, PpAGO3, plays a major role in the regulation of effector genes hence the pathogenicity of Phytophthora parasitica. PpAGO3 was unique among five predicted AGO genes in P. parasitica, showing strong mycelium stage-specific expression. Using the CRISPR-Cas9 technology, we generated PpAGO3ΔRGG1-3 mutants that carried a deletion of 1, 2, or 3 copies of the N-terminal RGG motif (QRGGYD) but failed to obtain complete knockout mutants, which suggests its vital role in P. parasitica. These mutants showed increased pathogenicity on both Nicotiana benthamiana and Arabidopsis thaliana plants. Transcriptome and sRNA sequencing of PpAGO3ΔRGG1 and PpAGO3ΔRGG3 showed that these mutants were differentially accumulated with 25–26 nt sRNAs associated with 70 predicted cytoplasmic effector genes compared to the wild-type, of which 13 exhibited inverse correlation between gene expression and 25–26 nt sRNA accumulation. Transient overexpression of the upregulated RXLR effector genes, PPTG_01869 and PPTG_15425 identified in the mutants PpAGO3ΔRGG1 and PpAGO3ΔRGG3, strongly enhanced N. benthamiana susceptibility to P. parasitica. Our results suggest that PpAGO3 functions together with 25–26 nt sRNAs to confer dynamic expression regulation of effector genes in P. parasitica, thereby contributing to infection and pathogenicity of the pathogen.
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Affiliation(s)
- Junjie Xu
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, China
| | - Yilin Li
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Agronomy, Northwest A&F University, Yangling, China
| | - Jinbu Jia
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, China
| | - Wenjing Xiong
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Agronomy, Northwest A&F University, Yangling, China
| | - Chengcheng Zhong
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, China
| | - Guiyan Huang
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, China
| | - Xiuhong Gou
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, China
| | - Yuling Meng
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Agronomy, Northwest A&F University, Yangling, China
| | - Weixing Shan
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Agronomy, Northwest A&F University, Yangling, China
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Hu X, Persson Hodén K, Liao Z, Åsman A, Dixelius C. Phytophthora infestans Ago1-associated miRNA promotes potato late blight disease. THE NEW PHYTOLOGIST 2022; 233:443-457. [PMID: 34605025 DOI: 10.1111/nph.17758] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 09/24/2021] [Indexed: 06/13/2023]
Abstract
Phytophthora spp. cause serious damage to plants by exploiting a large number of effector proteins and small RNAs (sRNAs). Several reports have described modulation of host RNA biogenesis and defence gene expression. Here, we analysed Phytophthora infestans Argonaute (Ago) 1 associated small RNAs during potato leaf infection. Small RNAs were co-immunoprecipitated, deep sequenced and analysed against the P. infestans and potato genomes, followed by transcript analyses and transgenic assays on a predicted target. Extensive targeting of potato and pathogen-derived sRNAs to a range of mRNAs was observed, including 638 sequences coding for resistance (R) proteins in the host genome. The single miRNA encoded by P. infestans (miR8788) was found to target a potato alpha/beta hydrolase-type encoding gene (StABH1), a protein localized to the plasma membrane. Analyses of stable transgenic potato lines harbouring overexpressed StABH1 or artificial miRNA gene constructs demonstrated the importance of StABH1 during infection by P. infestans. miR8788 knock-down strains showed reduced growth on potato, and elevated StABH1 expression levels were observed when plants were inoculated with the two knock-down strains compared to the wild-type strain 88069. The findings of our study suggest that sRNA encoded by P. infestans can affect potato mRNA, thereby expanding our knowledge of the multifaceted strategies this species uses to facilitate infection.
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Affiliation(s)
- Xinyi Hu
- Department of Plant Biology, Uppsala BioCenter, Linnean Center for Plant Biology, Swedish University of Agricultural Sciences, PO Box 7080, S-75007, Uppsala, Sweden
| | - Kristian Persson Hodén
- Department of Plant Biology, Uppsala BioCenter, Linnean Center for Plant Biology, Swedish University of Agricultural Sciences, PO Box 7080, S-75007, Uppsala, Sweden
| | - Zhen Liao
- Department of Plant Biology, Uppsala BioCenter, Linnean Center for Plant Biology, Swedish University of Agricultural Sciences, PO Box 7080, S-75007, Uppsala, Sweden
| | - Anna Åsman
- Department of Molecular Sciences, Uppsala BioCenter, Linnean Center for Plant Biology, Swedish University of Agricultural Sciences, PO Box 7015, S-75007, Uppsala, Sweden
| | - Christina Dixelius
- Department of Plant Biology, Uppsala BioCenter, Linnean Center for Plant Biology, Swedish University of Agricultural Sciences, PO Box 7080, S-75007, Uppsala, Sweden
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5
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Feng H, Wan C, Zhang Z, Chen H, Li Z, Jiang H, Yin M, Dong S, Dou D, Wang Y, Zheng X, Ye W. Specific interaction of an RNA-binding protein with the 3'-UTR of its target mRNA is critical to oomycete sexual reproduction. PLoS Pathog 2021; 17:e1010001. [PMID: 34648596 PMCID: PMC8547697 DOI: 10.1371/journal.ppat.1010001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 10/26/2021] [Accepted: 10/03/2021] [Indexed: 01/17/2023] Open
Abstract
Sexual reproduction is an essential stage of the oomycete life cycle. However, the functions of critical regulators in this biological process remain unclear due to a lack of genome editing technologies and functional genomic studies in oomycetes. The notorious oomycete pathogen Pythium ultimum is responsible for a variety of diseases in a broad range of plant species. In this study, we revealed the mechanism through which PuM90, a stage-specific Puf family RNA-binding protein, regulates oospore formation in P. ultimum. We developed the first CRISPR/Cas9 system-mediated gene knockout and in situ complementation methods for Pythium. PuM90-knockout mutants were significantly defective in oospore formation, with empty oogonia or oospores larger in size with thinner oospore walls compared with the wild type. A tripartite recognition motif (TRM) in the Puf domain of PuM90 could specifically bind to a UGUACAUA motif in the mRNA 3′ untranslated region (UTR) of PuFLP, which encodes a flavodoxin-like protein, and thereby repress PuFLP mRNA level to facilitate oospore formation. Phenotypes similar to PuM90-knockout mutants were observed with overexpression of PuFLP, mutation of key amino acids in the TRM of PuM90, or mutation of the 3′-UTR binding site in PuFLP. The results demonstrated that a specific interaction of the RNA-binding protein PuM90 with the 3′-UTR of PuFLP mRNA at the post-transcriptional regulation level is critical for the sexual reproduction of P. ultimum. Oomycetes are a class of eukaryotic microorganisms with life cycles and growth habits similar to filamentous fungi, but are not true fungi. Although sexual reproduction, which produce oospores, is an essential stage of life cycle, the functions of critical regulators in this biological process remain unclear due to a lack of genome editing technologies and functional genomic studies in oomycetes. In this study, we developed the first CRISPR/Cas9 system-mediated gene knockout and in situ complementation methods for Pythium ultimum, a notorious oomycete pathogen that is responsible for a variety of diseases in a broad range of plant species. We further identified the Puf family RNA-binding protein PuM90 and the flavodoxin-like protein PuFLP as major functional factors involved in P. ultimum oospore formation. We proposed a new model that PuM90 acts as a stage-specific post-transcriptional regulator by specifically binding to the 3′-UTR of PuFLP and then repressing PuFLP mRNA level. This study describes new technologies and data that will help to elucidate sexual reproduction and post-transcriptional regulation in oomycetes.
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Affiliation(s)
- Hui Feng
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, Jiangsu, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, Jiangsu, China
- The Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), Nanjing, Jiangsu, China
| | - Chuanxu Wan
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, Jiangsu, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, Jiangsu, China
- The Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), Nanjing, Jiangsu, China
| | - Zhichao Zhang
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, Jiangsu, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, Jiangsu, China
- The Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), Nanjing, Jiangsu, China
| | - Han Chen
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, Jiangsu, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, Jiangsu, China
- The Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), Nanjing, Jiangsu, China
| | - Zhipeng Li
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, Jiangsu, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, Jiangsu, China
- The Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), Nanjing, Jiangsu, China
| | - Haibin Jiang
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, Jiangsu, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, Jiangsu, China
- The Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), Nanjing, Jiangsu, China
| | - Maozhu Yin
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, Jiangsu, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, Jiangsu, China
- The Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), Nanjing, Jiangsu, China
| | - Suomeng Dong
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, Jiangsu, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, Jiangsu, China
- The Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), Nanjing, Jiangsu, China
| | - Daolong Dou
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, Jiangsu, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, Jiangsu, China
- The Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), Nanjing, Jiangsu, China
| | - Yuanchao Wang
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, Jiangsu, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, Jiangsu, China
- The Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), Nanjing, Jiangsu, China
| | - Xiaobo Zheng
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, Jiangsu, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, Jiangsu, China
- The Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), Nanjing, Jiangsu, China
| | - Wenwu Ye
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, Jiangsu, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, Jiangsu, China
- The Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), Nanjing, Jiangsu, China
- * E-mail:
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6
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Qiao Y, Xia R, Zhai J, Hou Y, Feng L, Zhai Y, Ma W. Small RNAs in Plant Immunity and Virulence of Filamentous Pathogens. ANNUAL REVIEW OF PHYTOPATHOLOGY 2021; 59:265-288. [PMID: 34077241 DOI: 10.1146/annurev-phyto-121520-023514] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Gene silencing guided by small RNAs governs a broad range of cellular processes in eukaryotes. Small RNAs are important components of plant immunity because they contribute to pathogen-triggered transcription reprogramming and directly target pathogen RNAs. Recent research suggests that silencing of pathogen genes by plant small RNAs occurs not only during viral infection but also in nonviral pathogens through a process termed host-induced gene silencing, which involves trans-species small RNA trafficking. Similarly, small RNAs are also produced by eukaryotic pathogens and regulate virulence. This review summarizes the small RNA pathways in both plants and filamentous pathogens, including fungi and oomycetes, and discusses their role in host-pathogen interactions. We highlight secondarysmall interfering RNAs of plants as regulators of immune receptor gene expression and executors of host-induced gene silencing in invading pathogens. The current status and prospects of trans-species gene silencing at the host-pathogen interface are discussed.
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Affiliation(s)
- Yongli Qiao
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai 200234, China;
| | - Rui Xia
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Horticulture, South China Agricultural University, Guangzhou 510640, China
| | - Jixian Zhai
- School of Life Sciences, Institute of Plant and Food Science, Southern University of Science and Technology, Shenzhen 518055, China
| | - Yingnan Hou
- Department of Microbiology and Plant Pathology, University of California, Riverside, California 92521, USA
| | - Li Feng
- School of Life Sciences, Institute of Plant and Food Science, Southern University of Science and Technology, Shenzhen 518055, China
| | - Yi Zhai
- Department of Microbiology and Plant Pathology, University of California, Riverside, California 92521, USA
| | - Wenbo Ma
- Department of Microbiology and Plant Pathology, University of California, Riverside, California 92521, USA
- The Sainsbury Laboratory, Norwich Research Park, Norwich, NR4 7UH, UK;
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7
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Dong S, Ma W. How to win a tug-of-war: the adaptive evolution of Phytophthora effectors. CURRENT OPINION IN PLANT BIOLOGY 2021; 62:102027. [PMID: 33684881 DOI: 10.1016/j.pbi.2021.102027] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Revised: 01/26/2021] [Accepted: 02/02/2021] [Indexed: 06/12/2023]
Abstract
The 'zigzag' model formulates some of the fundamental principles underpinning the dynamic interactions between pathogen effectors and plant immunity. As key virulence factors, effectors often exhibit a pattern of rapid evolution, presumably as a result of the host-pathogen arms race. Here, we summarize the current knowledge of mechanisms that may accelerate effector evolution in the highly successful Phytophthora pathogens. Recent findings on epigenetic regulation of effector genes that allows evasion of host recognition and maintenance of cost/benefit balance, and a conserved structural unit in effector proteins that may promote the evolution of virulence activities are highlighted.
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Affiliation(s)
- Suomeng Dong
- Department of Plant Pathology and Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, 210095, China.
| | - Wenbo Ma
- The Sainsbury Laboratory, Norwich Research Park, Norwich, NR4 7UH, United Kingdom; Department of Microbiology and Plant Pathology, University of California, Riverside, CA 92521, USA.
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8
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Hannat S, Pontarotti P, Colson P, Kuhn ML, Galiana E, La Scola B, Aherfi S, Panabières F. Diverse Trajectories Drive the Expression of a Giant Virus in the Oomycete Plant Pathogen Phytophthora parasitica. Front Microbiol 2021; 12:662762. [PMID: 34140938 PMCID: PMC8204020 DOI: 10.3389/fmicb.2021.662762] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 05/07/2021] [Indexed: 11/13/2022] Open
Abstract
Giant viruses of amoebas, recently classified in the class Megaviricetes, are a group of viruses that can infect major eukaryotic lineages. We previously identified a set of giant virus sequences in the genome of Phytophthora parasitica, an oomycete and a devastating major plant pathogen. How viral insertions shape the structure and evolution of the invaded genomes is unclear, but it is known that the unprecedented functional potential of giant viruses is the result of an intense genetic interplay with their hosts. We previously identified a set of giant virus sequences in the genome of P. parasitica, an oomycete and a devastating major plant pathogen. Here, we show that viral pieces are found in a 550-kb locus and are organized in three main clusters. Viral sequences, namely RNA polymerases I and II and a major capsid protein, were identified, along with orphan sequences, as a hallmark of giant viruses insertions. Mining of public databases and phylogenetic reconstructions suggest an ancient association of oomycetes and giant viruses of amoeba, including faustoviruses, African swine fever virus (ASFV) and pandoraviruses, and that a single viral insertion occurred early in the evolutionary history of oomycetes prior to the Phytophthora–Pythium radiation, estimated at ∼80 million years ago. Functional annotation reveals that the viral insertions are located in a gene sparse region of the Phytophthora genome, characterized by a plethora of transposable elements (TEs), effectors and other genes potentially involved in virulence. Transcription of viral genes was investigated through analysis of RNA-Seq data and qPCR experiments. We show that most viral genes are not expressed, and that a variety of mechanisms, including deletions, TEs insertions and RNA interference may contribute to transcriptional repression. However, a gene coding a truncated copy of RNA polymerase II along a set of neighboring sequences have been shown to be expressed in a wide range of physiological conditions, including responses to stress. These results, which describe for the first time the endogenization of a giant virus in an oomycete, contribute to challenge our view of Phytophthora evolution.
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Affiliation(s)
- Sihem Hannat
- Institut Hospitalo-Universitaire Méditerranée Infection, Marseille, France.,MEPHI, Institut de Recherche pour le Développement, Aix-Marseille Université, Marseille, France
| | - Pierre Pontarotti
- Institut Hospitalo-Universitaire Méditerranée Infection, Marseille, France.,MEPHI, Institut de Recherche pour le Développement, Aix-Marseille Université, Marseille, France.,CNRS SNC5039, Marseille, France
| | - Philippe Colson
- Institut Hospitalo-Universitaire Méditerranée Infection, Marseille, France.,MEPHI, Institut de Recherche pour le Développement, Aix-Marseille Université, Marseille, France.,Assistance Publique - Hôpitaux de Marseille, Marseille, France
| | - Marie-Line Kuhn
- INRAE, Université Côte d'Azur, CNRS, ISA, Sophia Antipolis, France
| | - Eric Galiana
- INRAE, Université Côte d'Azur, CNRS, ISA, Sophia Antipolis, France
| | - Bernard La Scola
- Institut Hospitalo-Universitaire Méditerranée Infection, Marseille, France.,MEPHI, Institut de Recherche pour le Développement, Aix-Marseille Université, Marseille, France
| | - Sarah Aherfi
- Institut Hospitalo-Universitaire Méditerranée Infection, Marseille, France.,MEPHI, Institut de Recherche pour le Développement, Aix-Marseille Université, Marseille, France.,Assistance Publique - Hôpitaux de Marseille, Marseille, France
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9
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Persson Hodén K, Hu X, Martinez G, Dixelius C. smartPARE: An R Package for Efficient Identification of True mRNA Cleavage Sites. Int J Mol Sci 2021; 22:4267. [PMID: 33924042 PMCID: PMC8073297 DOI: 10.3390/ijms22084267] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 04/14/2021] [Accepted: 04/17/2021] [Indexed: 11/30/2022] Open
Abstract
Degradome sequencing is commonly used to generate high-throughput information on mRNA cleavage sites mediated by small RNAs (sRNA). In our datasets of potato (Solanum tuberosum, St) and Phytophthora infestans (Pi), initial predictions generated high numbers of cleavage site predictions, which highlighted the need of improved analytic tools. Here, we present an R package based on a deep learning convolutional neural network (CNN) in a machine learning environment to optimize discrimination of false from true cleavage sites. When applying smartPARE to our datasets on potato during the infection process by the late blight pathogen, 7.3% of all cleavage windows represented true cleavages distributed on 214 sites in P. infestans and 444 sites in potato. The sRNA landscape of the two organisms is complex with uneven sRNA production and cleavage regions widespread in the two genomes. Multiple targets and several cases of complex regulatory cascades, particularly in potato, was revealed. We conclude that our new analytic approach is useful for anyone working on complex biological systems and with the interest of identifying cleavage sites particularly inferred by sRNA classes beyond miRNAs.
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Affiliation(s)
| | | | | | - Christina Dixelius
- The Swedish University of Agricultural Sciences, Department of Plant Biology, Uppsala BioCenter, Linnean Center for Plant Biology, P.O. Box 7080, S-75007 Uppsala, Sweden; (K.P.H.); (X.H.); (G.M.)
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10
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Meng X, Jin W, Wu F. Novel tomato miRNA miR1001 initiates cross-species regulation to suppress the conidiospore germination and infection virulence of Botrytis cinerea in vitro. Gene 2020; 759:145002. [PMID: 32726608 DOI: 10.1016/j.gene.2020.145002] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Revised: 07/19/2020] [Accepted: 07/22/2020] [Indexed: 12/24/2022]
Abstract
Recent evidence has shown that microRNAs are transferred from one species to another through cross-species transmission and exhibit biological activities in the receptor. However, the cross-kingdom regulation of pathogen virulence by plant-derived miRNAs is rarely reported. This study investigated the regulatory role of novel tomato miRNA miR1001 in the growth and development of Botrytis cinerea. Results showed that miR1001 inhibited the virulence of B. cinerea-infected plants, and the inhibitory effect of miR1001/miR1001* was stronger than that of miR1001. Moreover, miR1001 exerted a significant inhibitory effect on the conidiospore germination of B. cinerea. Degradome-seq experiment showed that miR1001 can directly target the Bcin03g02170.1 and Bcin10g01400.1 genes, which respectively encode the ATP-dependent metallopeptidase and cysteine-type endopeptidase, in B. cinerea. The interactions of both targets with miR1001 were further confirmed by using transient co-expression in tobacco. Real-time RT-PCR analysis showed that the expression levels of the two target genes were significantly downregulated in B. cinerea with miR1001 treatment. Our findings provide new evidence into the coevolution of pathogens and host plants, as well as new directions for the use of plant-derived miRNAs to control pathogens.
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Affiliation(s)
- Xin Meng
- Key Laboratory of Plant Secondary Metabolism and Regulation of Zhejiang Province, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Weibo Jin
- Key Laboratory of Plant Secondary Metabolism and Regulation of Zhejiang Province, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Fangli Wu
- Key Laboratory of Plant Secondary Metabolism and Regulation of Zhejiang Province, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, China.
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11
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Panabières F, Rancurel C, da Rocha M, Kuhn ML. Characterization of Two Satellite DNA Families in the Genome of the Oomycete Plant Pathogen Phytophthora parasitica. Front Genet 2020; 11:557. [PMID: 32582290 PMCID: PMC7290008 DOI: 10.3389/fgene.2020.00557] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Accepted: 05/07/2020] [Indexed: 12/13/2022] Open
Abstract
Satellite DNA is a class of repetitive sequences that are organized in long arrays of tandemly repeated units in most eukaryotes. Long considered as selfish DNA, satellite sequences are now proposed to contribute to genome integrity. Despite their potential impact on the architecture and evolution of the genome, satellite DNAs have not been investigated in oomycetes due to the paucity of genomic data and the difficulty of assembling highly conserved satellite arrays. Yet gaining knowledge on the structure and evolution of genomes of oomycete pathogens is crucial to understanding the mechanisms underlying adaptation to their environment and to proposing efficient disease control strategies. A de novo assembly of the genome of Phytophthora parasitica, an important oomycete plant pathogen, led to the identification of several families of tandemly repeated sequences varying in size, copy number, and sequence conservation. Among them, two abundant families, designated as PpSat1 and PpSat2, displayed typical features of satellite DNA and were collectively designated as PpSat. These two satellite families differ by their length, sequence, organization, genomic environment, and evolutionary dynamics. PpSat1, but not PpSat2, presented homologs among oomycetes. This observation, as well as the characterization of transcripts of PpSat families, suggested that these satellite DNA families likely play a conserved role within this important group of pathogens.
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12
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Bilir Ö, Telli O, Norman C, Budak H, Hong Y, Tör M. Small RNA inhibits infection by downy mildew pathogen Hyaloperonospora arabidopsidis. MOLECULAR PLANT PATHOLOGY 2019; 20:1523-1534. [PMID: 31557400 PMCID: PMC6804343 DOI: 10.1111/mpp.12863] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Gene silencing exists in eukaryotic organisms as a conserved regulation of the gene expression mechanism. In general, small RNAs (sRNAs) are produced within the eukaryotic cells and incorporated into an RNA-induced silencing complex (RISC) within cells. However, exogenous sRNAs, once delivered into cells, can also silence target genes via the same RISC. Here, we explored this concept by targeting the Cellulose synthase A3 (CesA3) gene of Hyaloperonospora arabidopsidis (Hpa), the downy mildew pathogen of Arabidopsis thaliana. Hpa spore suspensions were mixed with sense or antisense sRNAs and inoculated onto susceptible Arabidopsis seedlings. While sense sRNAs had no obvious effect on Hpa pathogenicity, antisense sRNAs inhibited spore germination and hence infection. Such inhibition of infection was not race-specific, but dependent on the length and capping of sRNAs. Inhibition of infection by double stranded sRNA was more efficient than that observed with antisense sRNA. Thus, exogenous sRNA targeting conserved CesA3 could suppress Hpa infection in Arabidopsis, indicating the potential of this simple and efficient sRNA-based approach for deciphering gene functions in obligate biotrophic pathogens as well as for R-gene independent control of diseases in plants.
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Affiliation(s)
- Özlem Bilir
- Department of BiologySchool of Science and the EnvironmentUniversity of WorcesterHenwick GroveWorcesterWR2 6AJUK
- Present address:
Directorate of Trakya Agricultural Research InstituteDepartment of BiotechnologyD‐100 Highway 22100EdirneTurkey
| | - Osman Telli
- Department of BiologySchool of Science and the EnvironmentUniversity of WorcesterHenwick GroveWorcesterWR2 6AJUK
| | - Chris Norman
- Department of BiologySchool of Science and the EnvironmentUniversity of WorcesterHenwick GroveWorcesterWR2 6AJUK
| | | | - Yiguo Hong
- Department of BiologySchool of Science and the EnvironmentUniversity of WorcesterHenwick GroveWorcesterWR2 6AJUK
- Research Centre for Plant RNA SignalingCollege of Life and Environmental SciencesHangzhou Normal UniversityHangzhou310036China
| | - Mahmut Tör
- Department of BiologySchool of Science and the EnvironmentUniversity of WorcesterHenwick GroveWorcesterWR2 6AJUK
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13
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Vu AL, Leesutthiphonchai W, Ah-Fong AMV, Judelson HS. Defining Transgene Insertion Sites and Off-Target Effects of Homology-Based Gene Silencing Informs the Application of Functional Genomics Tools in Phytophthora infestans. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2019; 32:915-927. [PMID: 30811313 DOI: 10.1094/mpmi-09-18-0265-ta] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
DNA transformation and homology-based transcriptional silencing are frequently used to assess gene function in Phytophthora spp. Since unplanned side-effects of these tools are not well-characterized, we used P. infestans to study plasmid integration sites and whether knockdowns caused by homology-dependent silencing spread to other genes. Insertions occurred both in gene-dense and gene-sparse regions but disproportionately near the 5' ends of genes, which disrupted native coding sequences. Microhomology at the recombination site between plasmid and chromosome was common. Studies of transformants silenced for 12 different gene targets indicated that neighbors within 500 nt were often cosilenced, regardless of whether hairpin or sense constructs were employed and the direction of transcription of the target. However, this cis spreading of silencing did not occur in all transformants obtained with the same plasmid. Genome-wide studies indicated that unlinked genes with partial complementarity with the silencing-inducing transgene were not usually down-regulated. We learned that hairpin or sense transgenes were not cosilenced with the target in all transformants, which informs how screens for silencing should be performed. We conclude that transformation and gene silencing can be reliable tools for functional genomics in Phytophthora spp. but must be used carefully, especially by testing for the spread of silencing to genes flanking the target.
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Affiliation(s)
- Andrea L Vu
- Department of Microbiology and Plant Pathology, University of California, Riverside, CA 92521, U.S.A
| | | | - Audrey M V Ah-Fong
- Department of Microbiology and Plant Pathology, University of California, Riverside, CA 92521, U.S.A
| | - Howard S Judelson
- Department of Microbiology and Plant Pathology, University of California, Riverside, CA 92521, U.S.A
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14
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Goulin EH, Galdeano DM, Granato LM, Matsumura EE, Dalio RJD, Machado MA. RNA interference and CRISPR: Promising approaches to better understand and control citrus pathogens. Microbiol Res 2019; 226:1-9. [PMID: 31284938 DOI: 10.1016/j.micres.2019.03.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 02/16/2019] [Accepted: 03/16/2019] [Indexed: 12/26/2022]
Abstract
Citrus crops have great economic importance worldwide. However, citrus production faces many diseases caused by different pathogens, such as bacteria, oomycetes, fungi and viruses. To overcome important plant diseases in general, new technologies have been developed and applied to crop protection, including RNA interference (RNAi) and clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated (Cas) systems. RNAi has been demonstrated to be a powerful tool for application in plant defence mechanisms against different pathogens as well as their respective vectors, and CRISPR/Cas system has become widely used in gene editing or reprogramming or knocking out any chosen DNA/RNA sequence. In this article, we provide an overview of the use of RNAi and CRISPR/Cas technologies in management strategies to control several plants diseases, and we discuss how these strategies can be potentially used against citrus pathogens.
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Affiliation(s)
- Eduardo Henrique Goulin
- Centro de Citricultura Sylvio Moreira/IAC, Rodovia Anhanguera, Km 158, Cordeiropolis, SP, Brazil.
| | - Diogo Manzano Galdeano
- Centro de Citricultura Sylvio Moreira/IAC, Rodovia Anhanguera, Km 158, Cordeiropolis, SP, Brazil
| | - Laís Moreira Granato
- Centro de Citricultura Sylvio Moreira/IAC, Rodovia Anhanguera, Km 158, Cordeiropolis, SP, Brazil
| | | | | | - Marcos Antonio Machado
- Centro de Citricultura Sylvio Moreira/IAC, Rodovia Anhanguera, Km 158, Cordeiropolis, SP, Brazil
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15
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Bollmann SR, Press CM, Tyler BM, Grünwald NJ. Expansion and Divergence of Argonaute Genes in the Oomycete Genus Phytophthora. Front Microbiol 2018; 9:2841. [PMID: 30555430 PMCID: PMC6284064 DOI: 10.3389/fmicb.2018.02841] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Accepted: 11/05/2018] [Indexed: 01/17/2023] Open
Abstract
Modulation of gene expression through RNA interference is well conserved in eukaryotes and is involved in many cellular processes. In the oomycete Phytophthora, research on the small RNA machinery and function has started to reveal potential roles in the pathogen, but much is still unknown. We examined Argonaute (AGO) homologs within oomycete genome sequences, especially among Phytophthora species, to gain a clearer understanding of the evolution of this well-conserved protein family. We identified AGO homologs across many representative oomycete and stramenopile species, and annotated representative homologs in P. sojae. Furthermore, we demonstrate variable transcript levels of all identified AGO homologs in comparison to previously identified Dicer-like (DCL) and RNA-dependent RNA polymerase (RDR) homologs. Our phylogenetic analysis further refines the relationship of the AGO homologs in oomycetes and identifies a conserved tandem duplication of AGO homologs in a subset of Phytophthora species.
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Affiliation(s)
- Stephanie R Bollmann
- Horticultural Crop Research Unit, Agricultural Research Service, United States Department of Agriculture, Corvallis, OR, United States
| | - Caroline M Press
- Horticultural Crop Research Unit, Agricultural Research Service, United States Department of Agriculture, Corvallis, OR, United States
| | - Brett M Tyler
- Department of Botany and Plant Pathology, Center for Genome Research and Biocomputing, Oregon State University, Corvallis, OR, United States
| | - Niklaus J Grünwald
- Horticultural Crop Research Unit, Agricultural Research Service, United States Department of Agriculture, Corvallis, OR, United States
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16
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Wang Y, Ye W, Wang Y. Genome-wide identification of long non-coding RNAs suggests a potential association with effector gene transcription in Phytophthora sojae. MOLECULAR PLANT PATHOLOGY 2018; 19:2177-2186. [PMID: 29665235 PMCID: PMC6638102 DOI: 10.1111/mpp.12692] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Revised: 03/14/2018] [Accepted: 04/12/2018] [Indexed: 05/08/2023]
Abstract
Numerous long non-coding RNAs (lncRNAs) identified and characterized in mammals, plants and fungi have been found to play critical regulatory roles in biological processes. However, little is known about the role of lncRNAs in oomycete plant pathogens, which cause devastating damage to the economy and ecosystems. We used strand-specific RNA sequencing (RNA-seq) to generate a computational pipeline to identify lncRNAs in Phytophthora sojae, a model oomycete plant pathogen. In total, 940 lncRNAs with 1010 isoforms were identified from RNA-seq data obtained from four representative stages of P. sojae. The lncRNAs had shorter transcript lengths, longer exon lengths, fewer numbers of exons, lower GC content and higher minimum free energy values compared with protein-coding genes. lncRNAs in P. sojae exhibited low sequence conservation amongst oomycetes and P. sojae isolates. Transcriptional data indicated that P. sojae lncRNAs tended to be transcribed in a stage-specific manner; representative lncRNAs were validated by semi-quantitative reverse transcription-polymerase chain reaction. Phytophthora sojae lncRNAs were concentrated in gene-sparse regions, and lncRNAs were associated with secreted protein and effector coding genes. The neighbouring genes of lncRNAs encoded various effector family members, and RNA-seq data revealed a correlation between the transcription level of lncRNAs and their neighbouring genes. Our results provide the first comprehensive identification of lncRNAs in oomycetes and suggest a potential association between lncRNAs and effector genes.
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Affiliation(s)
- Yang Wang
- Department of Plant PathologyNanjing Agricultural UniversityNanjingJiangsu 210095China
- The Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of EducationNanjingJiangsu 210095China
| | - Wenwu Ye
- Department of Plant PathologyNanjing Agricultural UniversityNanjingJiangsu 210095China
- The Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of EducationNanjingJiangsu 210095China
| | - Yuanchao Wang
- Department of Plant PathologyNanjing Agricultural UniversityNanjingJiangsu 210095China
- The Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of EducationNanjingJiangsu 210095China
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17
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Torres-Martínez S, Ruiz-Vázquez RM. The RNAi Universe in Fungi: A Varied Landscape of Small RNAs and Biological Functions. Annu Rev Microbiol 2017; 71:371-391. [PMID: 28657888 DOI: 10.1146/annurev-micro-090816-093352] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
RNA interference (RNAi) is a conserved eukaryotic mechanism that uses small RNA molecules to suppress gene expression through sequence-specific messenger RNA degradation, translational repression, or transcriptional inhibition. In filamentous fungi, the protective function of RNAi in the maintenance of genome integrity is well known. However, knowledge of the regulatory role of RNAi in fungi has had to wait until the recent identification of different endogenous small RNA classes, which are generated by distinct RNAi pathways. In addition, RNAi research on new fungal models has uncovered the role of small RNAs and RNAi pathways in the regulation of diverse biological functions. In this review, we give an up-to-date overview of the different classes of small RNAs and RNAi pathways in fungi and their roles in the defense of genome integrity and regulation of fungal physiology and development, as well as in the interaction of fungi with biotic and abiotic environments.
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18
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Jia J, Lu W, Zhong C, Zhou R, Xu J, Liu W, Gou X, Wang Q, Yin J, Xu C, Shan W. The 25-26 nt Small RNAs in Phytophthora parasitica Are Associated with Efficient Silencing of Homologous Endogenous Genes. Front Microbiol 2017; 8:773. [PMID: 28512457 PMCID: PMC5411455 DOI: 10.3389/fmicb.2017.00773] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2017] [Accepted: 04/13/2017] [Indexed: 02/01/2023] Open
Abstract
Small RNAs (sRNAs) are important non-coding RNA regulators, playing key roles in developmental regulation, transposon suppression, environmental response, host-pathogen interaction and other diverse biological processes. However, their roles in oomycetes are poorly understood. Here, we performed sRNA sequencing and RNA sequencing of Phytophthora parasitica at stages of vegetative growth and infection of Arabidopsis roots to examine diversity and function of sRNAs in P. parasitica, a model hemibiotrophic oomycete plant pathogen. Our results indicate that there are two distinct types of sRNA-generating loci in P. parasitica genome, giving rise to clusters of 25-26 nt and 21 nt sRNAs, respectively, with no significant strand-biases. The 25-26 nt sRNA loci lie predominantly in gene-sparse and repeat-rich regions, and overlap with over 7000 endogenous gene loci. These overlapped genes are typically P. parasitica species-specific, with no homologies to the sister species P. infestans. They include approximately 40% RXLR effector genes, 50% CRN effector genes and some elicitor genes. The transcripts of most of these genes could not be detected at both the vegetative mycelium and infection stages as revealed by RNA sequencing, indicating that the 25-26 nt sRNAs are associated with efficient silencing of these genes. The 21 nt sRNA loci typically overlap with the exon regions of highly expressed genes, suggesting that the biogenesis of the 21 nt sRNAs may be dependent on the level of gene transcription and that these sRNAs do not mediate efficient silencing of homologous genes. Analyses of the published P. infestans sRNA and mRNA sequencing data consistently show that the 25-26 nt sRNAs, but not the 21 nt sRNAs, may mediate efficient gene silencing in Phytophthora.
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Affiliation(s)
- Jinbu Jia
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F UniversityYangling, China
| | - Wenqin Lu
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F UniversityYangling, China
| | - Chengcheng Zhong
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F UniversityYangling, China
| | - Ran Zhou
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F UniversityYangling, China
| | - Junjie Xu
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F UniversityYangling, China
| | - Wei Liu
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F UniversityYangling, China
| | - Xiuhong Gou
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F UniversityYangling, China
| | - Qinhu Wang
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F UniversityYangling, China
| | - Junliang Yin
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F UniversityYangling, China
| | - Cheng Xu
- Chongqing Tobacco Research InstituteChongqing, China
| | - Weixing Shan
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F UniversityYangling, China.,State Key Laboratory of Crop Stress Biology for Arid Areas and College of Agronomy, Northwest A&F UniversityYangling, China
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19
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Derbyshire M, Denton-Giles M, Hegedus D, Seifbarghy S, Rollins J, van Kan J, Seidl MF, Faino L, Mbengue M, Navaud O, Raffaele S, Hammond-Kosack K, Heard S, Oliver R. The complete genome sequence of the phytopathogenic fungus Sclerotinia sclerotiorum reveals insights into the genome architecture of broad host range pathogens. Genome Biol Evol 2017; 9:593-618. [PMID: 28204478 PMCID: PMC5381539 DOI: 10.1093/gbe/evx030] [Citation(s) in RCA: 117] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Revised: 01/16/2017] [Accepted: 02/08/2017] [Indexed: 12/19/2022] Open
Abstract
Sclerotinia sclerotiorum is a phytopathogenic fungus with over 400 hosts including numerous economically important cultivated species. This contrasts many economically destructive pathogens that only exhibit a single or very few hosts. Many plant pathogens exhibit a “two-speed” genome. So described because their genomes contain alternating gene rich, repeat sparse and gene poor, repeat-rich regions. In fungi, the repeat-rich regions may be subjected to a process termed repeat-induced point mutation (RIP). Both repeat activity and RIP are thought to play a significant role in evolution of secreted virulence proteins, termed effectors. We present a complete genome sequence of S. sclerotiorum generated using Single Molecule Real-Time Sequencing technology with highly accurate annotations produced using an extensive RNA sequencing data set. We identified 70 effector candidates and have highlighted their in planta expression profiles. Furthermore, we characterized the genome architecture of S. sclerotiorum in comparison to plant pathogens that exhibit “two-speed” genomes. We show that there is a significant association between positions of secreted proteins and regions with a high RIP index in S. sclerotiorum but we did not detect a correlation between secreted protein proportion and GC content. Neither did we detect a negative correlation between CDS content and secreted protein proportion across the S. sclerotiorum genome. We conclude that S. sclerotiorum exhibits subtle signatures of enhanced mutation of secreted proteins in specific genomic compartments as a result of transposition and RIP activity. However, these signatures are not observable at the whole-genome scale.
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Affiliation(s)
- Mark Derbyshire
- Centre for Crop and Disease Management Department of Environment and Agriculture, Curtin University, Bentley, Perth, Western Australia, Australia
| | - Matthew Denton-Giles
- Centre for Crop and Disease Management Department of Environment and Agriculture, Curtin University, Bentley, Perth, Western Australia, Australia
| | - Dwayne Hegedus
- Agriculture and Agri-Food Canada, Saskatoon, Saskatchewan, Canada
| | | | - Jeffrey Rollins
- Department of Plant Pathology, University of Florida, Gainesville, FL
| | - Jan van Kan
- Laboratory of Phytopathology, Wageningen University, The Netherlands
| | - Michael F. Seidl
- Laboratory of Phytopathology, Wageningen University, The Netherlands
| | - Luigi Faino
- Laboratory of Phytopathology, Wageningen University, The Netherlands
| | - Malick Mbengue
- LIPM Université de Toulouse INRA CNRS, Castanet-Tolosan, France
| | - Olivier Navaud
- LIPM Université de Toulouse INRA CNRS, Castanet-Tolosan, France
| | | | - Kim Hammond-Kosack
- Department of Plant Biology and Crop Sciences, Rothamsted Research, Harpenden, Hertfordshire, United Kingdom
| | - Stephanie Heard
- Department of Plant Pathology, University of Florida, Gainesville, FL
- Department of Plant Biology and Crop Sciences, Rothamsted Research, Harpenden, Hertfordshire, United Kingdom
| | - Richard Oliver
- Centre for Crop and Disease Management Department of Environment and Agriculture, Curtin University, Bentley, Perth, Western Australia, Australia
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20
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de Vries S, von Dahlen JK, Uhlmann C, Schnake A, Kloesges T, Rose LE. Signatures of selection and host-adapted gene expression of the Phytophthora infestans RNA silencing suppressor PSR2. MOLECULAR PLANT PATHOLOGY 2017; 18:110-124. [PMID: 27503598 PMCID: PMC6638260 DOI: 10.1111/mpp.12465] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 07/07/2016] [Accepted: 08/04/2016] [Indexed: 05/04/2023]
Abstract
Phytophthora infestans is a devastating pathogen in agricultural systems. Recently, an RNA silencing suppressor (PSR2, 'Phytophthora suppressor of RNA silencing 2') has been described in P. infestans. PSR2 has been shown to increase the virulence of Phytophthora pathogens on their hosts. This gene is one of the few effectors present in many economically important Phytophthora species. In this study, we investigated: (i) the evolutionary history of PSR2 within and between species of Phytophthora; and (ii) the interaction between sequence variation, gene expression and virulence. In P. infestans, the highest PiPSR2 expression was correlated with decreased symptom expression. The highest gene expression was observed in the biotrophic phase of the pathogen, suggesting that PSR2 is important during early infection. Protein sequence conservation was negatively correlated with host range, suggesting host range as a driver of PSR2 evolution. Within species, we detected elevated amino acid variation, as observed for other effectors; however, the frequency spectrum of the mutations was inconsistent with strong balancing selection. This evolutionary pattern may be related to the conservation of the host target(s) of PSR2 and the absence of known corresponding R genes. In summary, our study indicates that PSR2 is a conserved effector that acts as a master switch to modify plant gene regulation early during infection for the pathogen's benefit. The conservation of PSR2 and its important role in virulence make it a promising target for pathogen management.
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Affiliation(s)
- Sophie de Vries
- Institute of Population GeneticsHeinrich‐Heine University DuesseldorfDuesseldorf40225Germany
- iGRAD‐Plant Graduate SchoolHeinrich‐Heine University DuesseldorfDuesseldorf40225Germany
| | - Janina K. von Dahlen
- Institute of Population GeneticsHeinrich‐Heine University DuesseldorfDuesseldorf40225Germany
| | - Constanze Uhlmann
- Institute of Population GeneticsHeinrich‐Heine University DuesseldorfDuesseldorf40225Germany
| | - Anika Schnake
- Institute of Population GeneticsHeinrich‐Heine University DuesseldorfDuesseldorf40225Germany
| | - Thorsten Kloesges
- Institute of Population GeneticsHeinrich‐Heine University DuesseldorfDuesseldorf40225Germany
| | - Laura E. Rose
- Institute of Population GeneticsHeinrich‐Heine University DuesseldorfDuesseldorf40225Germany
- iGRAD‐Plant Graduate SchoolHeinrich‐Heine University DuesseldorfDuesseldorf40225Germany
- Ceplas, Cluster of Excellence in Plant SciencesHeinrich‐Heine University DuesseldorfDuesseldorf40225Germany
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Whisson SC, Boevink PC, Wang S, Birch PR. The cell biology of late blight disease. Curr Opin Microbiol 2016; 34:127-135. [PMID: 27723513 PMCID: PMC5340842 DOI: 10.1016/j.mib.2016.09.002] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 09/01/2016] [Accepted: 09/08/2016] [Indexed: 11/12/2022]
Abstract
The Phytophthora haustorium is a major site of secretion during infection. The host endocytic cycle contributes to biogenesis of the Extra-Haustorial Membrane. RXLR effectors manipulate host processes at diverse subcellular locations. They directly manipulate the activity or location of immune proteins. They also promote the activity of endogenous negative regulators of immunity.
Late blight, caused by the oomycete Phytophthora infestans, is a major global disease of potato and tomato. Cell biology is teaching us much about the developmental stages associated with infection, especially the haustorium, which is a site of intimate interaction and molecular exchange between pathogen and host. Recent observations suggest a role for the plant endocytic cycle in specific recruitment of host proteins to the Extra-Haustorial Membrane, emphasising the unique nature of this membrane compartment. In addition, there has been a strong focus on the activities of RXLR effectors, which are delivered into plant cells to modulate and manipulate host processes. RXLR effectors interact directly with diverse plant proteins at a range of subcellular locations to promote disease.
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Affiliation(s)
- Stephen C Whisson
- Cell and Molecular Sciences, James Hutton Institute, Errol Road, Invergowrie, Dundee DD2 5DA, UK
| | - Petra C Boevink
- Cell and Molecular Sciences, James Hutton Institute, Errol Road, Invergowrie, Dundee DD2 5DA, UK
| | - Shumei Wang
- Division of Plant Sciences, University of Dundee, James Hutton Institute, Invergowrie, Dundee DD2 5DA, UK
| | - Paul Rj Birch
- Cell and Molecular Sciences, James Hutton Institute, Errol Road, Invergowrie, Dundee DD2 5DA, UK; Division of Plant Sciences, University of Dundee, James Hutton Institute, Invergowrie, Dundee DD2 5DA, UK.
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Palma-Martínez I, Guerrero-Mandujano A, Ruiz-Ruiz MJ, Hernández-Cortez C, Molina-López J, Bocanegra-García V, Castro-Escarpulli G. Active Shiga-Like Toxin Produced by Some Aeromonas spp., Isolated in Mexico City. Front Microbiol 2016; 7:1552. [PMID: 27757103 PMCID: PMC5048074 DOI: 10.3389/fmicb.2016.01552] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Accepted: 09/16/2016] [Indexed: 12/29/2022] Open
Abstract
RNA silencing is a conserved mechanism that utilizes small RNAs (sRNAs) to direct the regulation of gene expression at the transcriptional or post-transcriptional level. Plants utilizing RNA silencing machinery to defend pathogen infection was first identified in plant–virus interaction and later was observed in distinct plant–pathogen interactions. RNA silencing is not only responsible for suppressing RNA accumulation and movement of virus and viroid, but also facilitates plant immune responses against bacterial, oomycete, and fungal infection. Interestingly, even the same plant sRNA can perform different roles when encounters with different pathogens. On the other side, pathogens counteract by generating sRNAs that directly regulate pathogen gene expression to increase virulence or target host genes to facilitate pathogen infection. Here, we summarize the current knowledge of the characterization and biogenesis of host- and pathogen-derived sRNAs, as well as the different RNA silencing machineries that plants utilize to defend against different pathogens. The functions of these sRNAs in defense and counter-defense and their mechanisms for regulation during different plant–pathogen interactions are also discussed.
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Affiliation(s)
- Ingrid Palma-Martínez
- Laboratorio de Bacteriología Médica, Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional Mexico City, Mexico
| | - Andrea Guerrero-Mandujano
- Laboratorio de Bacteriología Médica, Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional Mexico City, Mexico
| | - Manuel J Ruiz-Ruiz
- Laboratorio de Bacteriología Médica, Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico NacionalMexico City, Mexico; Laboratorio Central de Análisis Clínicos Unidad Médica de Alta Especialidad Hospital de Pediatría "Silvestre Frenk Freund," Centro Médico Nacional Siglo XXIMexico City, Mexico
| | - Cecilia Hernández-Cortez
- Laboratorio de Bacteriología Médica, Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico NacionalMexico City, Mexico; Laboratorio de Bioquímica Microbiana, Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico NacionalMexico City, Mexico
| | - José Molina-López
- Departamento de Salud Pública, Facultad de Medicina, Universidad Nacional Autónoma de México Mexico City, Mexico
| | | | - Graciela Castro-Escarpulli
- Laboratorio de Bacteriología Médica, Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional Mexico City, Mexico
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Affiliation(s)
- Ren Na
- Department of Biology, University of Western Ontario, London, Ontario, Canada
- Agriculture and Agri-Food Canada, London, Ontario, Canada
| | - Mark Gijzen
- Department of Biology, University of Western Ontario, London, Ontario, Canada
- Agriculture and Agri-Food Canada, London, Ontario, Canada
- * E-mail:
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