1
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Ahn E, Prom LK, Park S, Hu Z, Magill CW. Genome-Wide Association Analysis Uncovers Genes Associated with Resistance to Head Smut Pathotype 5 in Senegalese Sorghum Accessions. PLANTS (BASEL, SWITZERLAND) 2024; 13:977. [PMID: 38611506 PMCID: PMC11013943 DOI: 10.3390/plants13070977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Revised: 03/18/2024] [Accepted: 03/27/2024] [Indexed: 04/14/2024]
Abstract
A newly documented pathotype 5 of the soil-borne fungus Sporisorium reilianum, causing head smut in sorghum, was tested against 153 unexplored Senegalese sorghum accessions. Among the 153 sorghum accessions tested, 63 (41%) exhibited complete resistance, showing no signs of infection by the fungus. The remaining 90 accessions (59%) displayed varying degrees of susceptibility. Sorghum responses against S. reilianum were explored to analyze the potential link with previously known seed morphology-related traits and new phenotype data from 59 lines for seed weight. A genome-wide association study (GWAS) screened 297,876 SNPs and identified highly significant associations (p < 1 × 10-5) with head smut resistance in sorghum. By mapping these significant SNPs to the reference genome, this study revealed 35 novel candidate defense genes potentially involved in disease resistance.
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Affiliation(s)
- Ezekiel Ahn
- USDA-ARS Sustainable Perennial Crops Laboratory, Beltsville Agricultural Research Center, Beltsville, MD 20705, USA;
| | - Louis K. Prom
- USDA-ARS Southern Plains Agricultural Research Center, College Station, TX 77845, USA;
| | - Sunchung Park
- USDA-ARS Sustainable Perennial Crops Laboratory, Beltsville Agricultural Research Center, Beltsville, MD 20705, USA;
| | - Zhenbin Hu
- USDA-ARS Animal Genomics and Improvement Laboratory, Beltsville Agricultural Research Center, Beltsville, MD 20705, USA;
| | - Clint W. Magill
- Department of Plant Pathology & Microbiology, Texas A&M University, College Station, TX 77843, USA
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2
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Miyahara T, Ohkubo H, Umeyama Y, Oguchi T, Ogawa T, Ohta D, Mochizuki T, Kodama H. Discontinuous Translocation of a Luciferase Protein beyond Graft Junction in Tobacco. Food Saf (Tokyo) 2024; 12:1-16. [PMID: 38532775 PMCID: PMC10961615 DOI: 10.14252/foodsafetyfscj.d-23-00010] [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: 09/25/2023] [Accepted: 01/29/2024] [Indexed: 03/28/2024] Open
Abstract
Transgrafting, a grafting technique that uses both genetically modified (GM) and non-GM plants, is a novel plant breeding technology that can be used to improve the efficiency of crop cultivation without introducing foreign genes into the edible parts of non-GM plants. This technique can facilitate the acquisition of disease resistance and/or increased yield. However, the translocation of low-molecular-weight compounds, ribonucleic acid (RNA), and proteins through graft junctions raises a potential safety risk for food crops. Here, we used a transgenic tobacco plant expressing a firefly luciferase gene (LUC) to examine the translocation of the LUC protein beyond the graft junction in grafted plants. We observed the bi-directional translocation of LUC proteins in transgrafted tobacco plants, i.e., from the rootstock to scion and vice versa. Transcriptomic analysis revealed that transcripts of the LUC gene were undetectable in non-GM plant bodies, indicating that the LUC protein itself was translocated. Moreover, the movement of the LUC protein is an episodic (i.e., non-continuous) event, since non-GM samples showing high LUC activity were flanked by non-GM samples showing no apparent LUC activity. Translocation from the GM to non-GM part depends on the characteristics of GM plant bodies; here, the enhanced translocation of the LUC protein into the non-GM scion was observed when LUC-expressing rootstocks with hairy roots were used. Moreover, the quantity of translocated LUC protein was far below the level that is generally required to induce an allergenic response. Finally, since the LUC protein levels of plants used for transgrafting are moderate and the LUC protein itself is relatively unstable, further investigation is necessary regarding whether the newly expressed protein in GM plants is highly stable, easily translocated, and/or highly expressed.
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Affiliation(s)
- Taira Miyahara
- Graduate School of Horticulture, Chiba University, 1-33
Yayoi-cho, Inage-ku, Chiba 263-8522, Japan
| | - Hitomi Ohkubo
- Graduate School of Horticulture, Chiba University, 1-33
Yayoi-cho, Inage-ku, Chiba 263-8522, Japan
| | - Yukiko Umeyama
- Graduate School of Horticulture, Chiba University, 1-33
Yayoi-cho, Inage-ku, Chiba 263-8522, Japan
| | - Taichi Oguchi
- Institute of Life and Environmental Sciences, University of
Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan
- Tsukuba Plant Innovation Research Center, University of Tsukuba,
1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan
| | - Takumi Ogawa
- Graduate School of Agriculture, Osaka Metropolitan University,
1-1 Gakuen-cho, Naka-ku, Sakai,Osaka 599-8531, Japan
- Graduate School of Life and Environmental Sciences, Osaka
Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8531, Japan
| | - Daisaku Ohta
- Graduate School of Agriculture, Osaka Metropolitan University,
1-1 Gakuen-cho, Naka-ku, Sakai,Osaka 599-8531, Japan
- Graduate School of Life and Environmental Sciences, Osaka
Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8531, Japan
| | - Tomofumi Mochizuki
- Graduate School of Agriculture, Osaka Metropolitan University,
1-1 Gakuen-cho, Naka-ku, Sakai,Osaka 599-8531, Japan
- Graduate School of Life and Environmental Sciences, Osaka
Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8531, Japan
| | - Hiroaki Kodama
- Graduate School of Horticulture, Chiba University, 1-33
Yayoi-cho, Inage-ku, Chiba 263-8522, Japan
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3
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Talbi N, Blekemolen MC, Janevska S, Zendler D, van Tilbeurgh H, Fudal I, Takken FLW. Facilitation of Symplastic Effector Protein Mobility by Paired Effectors Is Conserved in Different Classes of Fungal Pathogens. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2024; 37:304-314. [PMID: 37782126 DOI: 10.1094/mpmi-07-23-0103-fi] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/03/2023]
Abstract
It has been discovered that plant pathogens produce effectors that spread via plasmodesmata (PD) to allow modulation of host processes in distal uninfected cells. Fusarium oxysporum f. sp. lycopersici (Fol) facilitates effector translocation by expansion of the size-exclusion limit of PD using the Six5/Avr2 effector pair. How other fungal pathogens manipulate PD is unknown. We recently reported that many fungal pathogens belonging to different families carry effector pairs that resemble the SIX5/AVR2 gene pair from Fol. Here, we performed structural predictions of three of these effector pairs from Leptosphaeria maculans (Lm) and tested their ability to manipulate PD and to complement the virulence defect of a Fol SIX5 knockout mutant. We show that the AvrLm10A homologs are structurally related to FolSix5 and localize at PD when they are expressed with their paired effectors. Furthermore, these effectors were found to complement FolSix5 function in cell-to-cell mobility assays and in fungal virulence. We conclude that distantly related fungal species rely on structurally related paired effector proteins to manipulate PD and facilitate effector mobility. The wide distribution of these effector pairs implies Six5-mediated effector translocation to be a conserved propensity among fungal plant pathogens. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Affiliation(s)
- Nacera Talbi
- Université Paris-Saclay, INRAE, UR BIOGER, 91120 Palaiseau, France
| | - Mila C Blekemolen
- Molecular Plant Pathology, Swammerdam Institute of Life Science (SILS), University of Amsterdam, Amsterdam, the Netherlands
| | - Slavica Janevska
- Molecular Plant Pathology, Swammerdam Institute of Life Science (SILS), University of Amsterdam, Amsterdam, the Netherlands
| | - Daniel Zendler
- Molecular Plant Pathology, Swammerdam Institute of Life Science (SILS), University of Amsterdam, Amsterdam, the Netherlands
| | - Herman van Tilbeurgh
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Isabelle Fudal
- Université Paris-Saclay, INRAE, UR BIOGER, 91120 Palaiseau, France
| | - Frank L W Takken
- Molecular Plant Pathology, Swammerdam Institute of Life Science (SILS), University of Amsterdam, Amsterdam, the Netherlands
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4
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Zhang M, Cheng W, Wang J, Cheng T, Lin X, Zhang Q, Li C. Genome-Wide Identification of Callose Synthase Family Genes and Their Expression Analysis in Floral Bud Development and Hormonal Responses in Prunus mume. PLANTS (BASEL, SWITZERLAND) 2023; 12:4159. [PMID: 38140486 PMCID: PMC10748206 DOI: 10.3390/plants12244159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 12/07/2023] [Accepted: 12/10/2023] [Indexed: 12/24/2023]
Abstract
Callose is an important polysaccharide composed of beta-1,3-glucans and is widely implicated in plant development and defense responses. Callose synthesis is mainly catalyzed by a family of callose synthases, also known as glucan synthase-like (GSL) enzymes. Despite the fact that GSL family genes were studied in a few plant species, their functional roles have not been fully understood in woody perennials. In this study, we identified total of 84 GSL genes in seven plant species and classified them into six phylogenetic clades. An evolutionary analysis revealed different modes of duplication driving the expansion of GSL family genes in monocot and dicot species, with strong purifying selection constraining the protein evolution. We further examined the gene structure, protein sequences, and physiochemical properties of 11 GSL enzymes in Prunus mume and observed strong sequence conservation within the functional domain of PmGSL proteins. However, the exon-intron distribution and protein motif composition are less conservative among PmGSL genes. With a promoter analysis, we detected abundant hormonal responsive cis-acting elements and we inferred the putative transcription factors regulating PmGSLs. To further understand the function of GSL family genes, we analyzed their expression patterns across different tissues, and during the process of floral bud development, pathogen infection, and hormonal responses in Prunus species and identified multiple GSL gene members possibly implicated in the callose deposition associated with bud dormancy cycling, pathogen infection, and hormone signaling. In summary, our study provides a comprehensive understanding of GSL family genes in Prunus species and has laid the foundation for future functional research of callose synthase genes in perennial trees.
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Affiliation(s)
- Man Zhang
- Beijing Key Laboratory of Ornamental Plants Germplasm Innovation & Molecular Breeding, National Engineering Research Center for Floriculture, Beijing Laboratory of Urban and Rural Ecological Environment, Engineering Research Center of Landscape Environment of Ministry of Education, Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants of Ministry of Education, School of Landscape Architecture, Beijing Forestry University, Beijing 100083, China; (M.Z.); (W.C.); (J.W.); (T.C.)
| | - Wenhui Cheng
- Beijing Key Laboratory of Ornamental Plants Germplasm Innovation & Molecular Breeding, National Engineering Research Center for Floriculture, Beijing Laboratory of Urban and Rural Ecological Environment, Engineering Research Center of Landscape Environment of Ministry of Education, Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants of Ministry of Education, School of Landscape Architecture, Beijing Forestry University, Beijing 100083, China; (M.Z.); (W.C.); (J.W.); (T.C.)
| | - Jia Wang
- Beijing Key Laboratory of Ornamental Plants Germplasm Innovation & Molecular Breeding, National Engineering Research Center for Floriculture, Beijing Laboratory of Urban and Rural Ecological Environment, Engineering Research Center of Landscape Environment of Ministry of Education, Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants of Ministry of Education, School of Landscape Architecture, Beijing Forestry University, Beijing 100083, China; (M.Z.); (W.C.); (J.W.); (T.C.)
| | - Tangren Cheng
- Beijing Key Laboratory of Ornamental Plants Germplasm Innovation & Molecular Breeding, National Engineering Research Center for Floriculture, Beijing Laboratory of Urban and Rural Ecological Environment, Engineering Research Center of Landscape Environment of Ministry of Education, Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants of Ministry of Education, School of Landscape Architecture, Beijing Forestry University, Beijing 100083, China; (M.Z.); (W.C.); (J.W.); (T.C.)
| | - Xinlian Lin
- Flower Research Institute, Meizhou Academy of Agriculture and Forestry Sciences, Meizhou 514071, China;
| | - Qixiang Zhang
- Beijing Key Laboratory of Ornamental Plants Germplasm Innovation & Molecular Breeding, National Engineering Research Center for Floriculture, Beijing Laboratory of Urban and Rural Ecological Environment, Engineering Research Center of Landscape Environment of Ministry of Education, Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants of Ministry of Education, School of Landscape Architecture, Beijing Forestry University, Beijing 100083, China; (M.Z.); (W.C.); (J.W.); (T.C.)
| | - Cuiling Li
- Flower Research Institute, Meizhou Academy of Agriculture and Forestry Sciences, Meizhou 514071, China;
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5
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Atabekova AK, Solovieva AD, Chergintsev DA, Solovyev AG, Morozov SY. Role of Plant Virus Movement Proteins in Suppression of Host RNAi Defense. Int J Mol Sci 2023; 24:ijms24109049. [PMID: 37240394 DOI: 10.3390/ijms24109049] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 05/18/2023] [Accepted: 05/19/2023] [Indexed: 05/28/2023] Open
Abstract
One of the systems of plant defense against viral infection is RNA silencing, or RNA interference (RNAi), in which small RNAs derived from viral genomic RNAs and/or mRNAs serve as guides to target an Argonaute nuclease (AGO) to virus-specific RNAs. Complementary base pairing between the small interfering RNA incorporated into the AGO-based protein complex and viral RNA results in the target cleavage or translational repression. As a counter-defensive strategy, viruses have evolved to acquire viral silencing suppressors (VSRs) to inhibit the host plant RNAi pathway. Plant virus VSR proteins use multiple mechanisms to inhibit silencing. VSRs are often multifunctional proteins that perform additional functions in the virus infection cycle, particularly, cell-to-cell movement, genome encapsidation, or replication. This paper summarizes the available data on the proteins with dual VSR/movement protein activity used by plant viruses of nine orders to override the protective silencing response and reviews the different molecular mechanisms employed by these proteins to suppress RNAi.
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Affiliation(s)
- Anastasia K Atabekova
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, 119992 Moscow, Russia
| | - Anna D Solovieva
- Department of Virology, Biological Faculty, Moscow State University, 119234 Moscow, Russia
| | - Denis A Chergintsev
- Department of Virology, Biological Faculty, Moscow State University, 119234 Moscow, Russia
| | - Andrey G Solovyev
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, 119992 Moscow, Russia
- Department of Virology, Biological Faculty, Moscow State University, 119234 Moscow, Russia
| | - Sergey Y Morozov
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, 119992 Moscow, Russia
- Department of Virology, Biological Faculty, Moscow State University, 119234 Moscow, Russia
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6
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German L, Yeshvekar R, Benitez‐Alfonso Y. Callose metabolism and the regulation of cell walls and plasmodesmata during plant mutualistic and pathogenic interactions. PLANT, CELL & ENVIRONMENT 2023; 46:391-404. [PMID: 36478232 PMCID: PMC10107507 DOI: 10.1111/pce.14510] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 11/21/2022] [Accepted: 12/05/2022] [Indexed: 06/17/2023]
Abstract
Cell walls are essential for plant growth and development, providing support and protection from external environments. Callose is a glucan that accumulates in specialized cell wall microdomains including around intercellular pores called plasmodesmata. Despite representing a small percentage of the cell wall (~0.3% in the model plant Arabidopsis thaliana), callose accumulation regulates important biological processes such as phloem and pollen development, cell division, organ formation, responses to pathogenic invasion and to changes in nutrients and toxic metals in the soil. Callose accumulation modifies cell wall properties and restricts plasmodesmata aperture, affecting the transport of signaling proteins and RNA molecules that regulate plant developmental and environmental responses. Although the importance of callose, at and outside plasmodesmata cell walls, is widely recognized, the underlying mechanisms controlling changes in its synthesis and degradation are still unresolved. In this review, we explore the most recent literature addressing callose metabolism with a focus on the molecular factors affecting callose accumulation in response to mutualistic symbionts and pathogenic elicitors. We discuss commonalities in the signaling pathways, identify research gaps and highlight opportunities to target callose in the improvement of plant responses to beneficial versus pathogenic microbes.
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Affiliation(s)
- Liam German
- Centre for Plant Sciences, School of BiologyUniversity of LeedsLeedsUK
| | - Richa Yeshvekar
- Centre for Plant Sciences, School of BiologyUniversity of LeedsLeedsUK
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7
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Blekemolen MC, Cao L, Tintor N, de Groot T, Papp D, Faulkner C, Takken FLW. The primary function of Six5 of Fusarium oxysporum is to facilitate Avr2 activity by together manipulating the size exclusion limit of plasmodesmata. FRONTIERS IN PLANT SCIENCE 2022; 13:910594. [PMID: 35968143 PMCID: PMC9373983 DOI: 10.3389/fpls.2022.910594] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 07/06/2022] [Indexed: 06/15/2023]
Abstract
Pathogens produce effector proteins to manipulate their hosts. While most effectors act autonomously, some fungal effectors act in pairs and rely on each other for function. During the colonization of the plant vasculature, the root-infecting fungus Fusarium oxysporum (Fo) produces 14 so-called Secreted in Xylem (SIX) effectors. Two of these effector genes, Avr2 (Six3) and Six5, form a gene pair on the pathogenicity chromosome of the tomato-infecting Fo strain. Avr2 has been shown to suppress plant defense responses and is required for full pathogenicity. Although Six5 and Avr2 together manipulate the size exclusion limit of plasmodesmata to facilitate cell-to-cell movement of Avr2, it is unclear whether Six5 has additional functions as well. To investigate the role of Six5, we generated transgenic Arabidopsis lines expressing Six5. Notably, increased susceptibility during the early stages of infection was observed in these Six5 lines, but only to Fo strains expressing Avr2 and not to wild-type Arabidopsis-infecting Fo strains lacking this effector gene. Furthermore, neither PAMP-triggered defense responses, such as ROS accumulation and callose deposition upon treatment with Flg22, necrosis and ethylene-inducing peptide 1-like protein (NLP), or chitosan, nor susceptibility to other plant pathogens, such as the bacterium Pseudomonas syringae or the fungus Verticilium dahlia, were affected by Six5 expression. Further investigation of the ability of the Avr2/Six5 effector pair to manipulate plasmodesmata (PD) revealed that it not only permits cell-to-cell movement of Avr2, but also facilitates the movement of two additional effectors, Six6 and Six8. Moreover, although Avr2/Six5 expands the size exclusion limit of plasmodesmata (i.e., gating) to permit the movement of a 2xFP fusion protein (53 kDa), a larger variant, 3xFP protein (80 kDa), did not move to the neighboring cells. The PD manipulation mechanism employed by Avr2/Six5 did not involve alteration of callose homeostasis in these structures. In conclusion, the primary function of Six5 appears to function together with Avr2 to increase the size exclusion limit of plasmodesmata by an unknown mechanism to facilitate cell-to-cell movement of Fo effectors.
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Affiliation(s)
- Mila C. Blekemolen
- Molecular Plant Pathology, Swammerdam Institute of Life Science (SILS), University of Amsterdam, Amsterdam, Netherlands
| | - Lingxue Cao
- Molecular Plant Pathology, Swammerdam Institute of Life Science (SILS), University of Amsterdam, Amsterdam, Netherlands
| | - Nico Tintor
- Molecular Plant Pathology, Swammerdam Institute of Life Science (SILS), University of Amsterdam, Amsterdam, Netherlands
| | - Tamara de Groot
- Molecular Plant Pathology, Swammerdam Institute of Life Science (SILS), University of Amsterdam, Amsterdam, Netherlands
| | - Diana Papp
- The John Innes Centre, Norwich Research Park, Norwich, United Kingdom
| | | | - Frank L. W. Takken
- Molecular Plant Pathology, Swammerdam Institute of Life Science (SILS), University of Amsterdam, Amsterdam, Netherlands
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8
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Action Mechanisms of Effectors in Plant-Pathogen Interaction. Int J Mol Sci 2022; 23:ijms23126758. [PMID: 35743201 PMCID: PMC9224169 DOI: 10.3390/ijms23126758] [Citation(s) in RCA: 38] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 06/09/2022] [Accepted: 06/15/2022] [Indexed: 02/08/2023] Open
Abstract
Plant pathogens are one of the main factors hindering the breeding of cash crops. Pathogens, including oomycetes, fungus, and bacteria, secrete effectors as invasion weapons to successfully invade and propagate in host plants. Here, we review recent advances made in the field of plant-pathogen interaction models and the action mechanisms of phytopathogenic effectors. The review illustrates how effectors from different species use similar and distinct strategies to infect host plants. We classify the main action mechanisms of effectors in plant-pathogen interactions according to the infestation process: targeting physical barriers for disruption, creating conditions conducive to infestation, protecting or masking themselves, interfering with host cell physiological activity, and manipulating plant downstream immune responses. The investigation of the functioning of plant pathogen effectors contributes to improved understanding of the molecular mechanisms of plant-pathogen interactions. This understanding has important theoretical value and is of practical significance in plant pathology and disease resistance genetics and breeding.
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9
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Roles of RNA silencing in viral and non-viral plant immunity and in the crosstalk between disease resistance systems. Nat Rev Mol Cell Biol 2022; 23:645-662. [PMID: 35710830 DOI: 10.1038/s41580-022-00496-5] [Citation(s) in RCA: 65] [Impact Index Per Article: 32.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/04/2022] [Indexed: 11/08/2022]
Abstract
RNA silencing is a well-established antiviral immunity system in plants, in which small RNAs guide Argonaute proteins to targets in viral RNA or DNA, resulting in virus repression. Virus-encoded suppressors of silencing counteract this defence system. In this Review, we discuss recent findings about antiviral RNA silencing, including the movement of RNA through plasmodesmata and the differentiation between plant self and viral RNAs. We also discuss the emerging role of RNA silencing in plant immunity against non-viral pathogens. This immunity is mediated by transkingdom movement of RNA into and out of the infected plant cells in vesicles or as extracellular nucleoproteins and, like antiviral immunity, is influenced by the silencing suppressors encoded in the pathogens' genomes. Another effect of RNA silencing on general immunity involves host-encoded small RNAs, including microRNAs, that regulate NOD-like receptors and defence signalling pathways in the innate immunity system of plants. These RNA silencing pathways form a network of processes with both positive and negative effects on the immune systems of plants.
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10
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Iswanto ABB, Vu MH, Pike S, Lee J, Kang H, Son GH, Kim J, Kim SH. Pathogen effectors: What do they do at plasmodesmata? MOLECULAR PLANT PATHOLOGY 2022; 23:795-804. [PMID: 34569687 PMCID: PMC9104267 DOI: 10.1111/mpp.13142] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 09/10/2021] [Accepted: 09/10/2021] [Indexed: 06/13/2023]
Abstract
Plants perceive an assortment of external cues during their life cycle, including abiotic and biotic stressors. Biotic stress from a variety of pathogens, including viruses, oomycetes, fungi, and bacteria, is considered to be a substantial factor hindering plant growth and development. To hijack the host cell's defence machinery, plant pathogens have evolved sophisticated attack strategies mediated by numerous effector proteins. Several studies have indicated that plasmodesmata (PD), symplasmic pores that facilitate cell-to-cell communication between a cell and neighbouring cells, are one of the targets of pathogen effectors. However, in contrast to plant-pathogenic viruses, reports of fungal- and bacterial-encoded effectors that localize to and exploit PD are limited. Surprisingly, a recent study of PD-associated bacterial effectors has shown that a number of bacterial effectors undergo cell-to-cell movement via PD. Here we summarize and highlight recent advances in the study of PD-associated fungal/oomycete/bacterial effectors. We also discuss how pathogen effectors interfere with host defence mechanisms in the context of PD regulation.
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Affiliation(s)
- Arya Bagus Boedi Iswanto
- Division of Applied Life Science (BK21 Four Program)Plant Molecular Biology and Biotechnology Research CenterGyeongsang National UniversityJinjuRepublic of Korea
| | - Minh Huy Vu
- Division of Applied Life Science (BK21 Four Program)Plant Molecular Biology and Biotechnology Research CenterGyeongsang National UniversityJinjuRepublic of Korea
| | - Sharon Pike
- Division of Plant SciencesChristopher S. Bond Life Sciences Center and Interdisciplinary Plant GroupUniversity of MissouriColumbiaMissouriUSA
| | - Jihyun Lee
- Division of Applied Life Science (BK21 Four Program)Plant Molecular Biology and Biotechnology Research CenterGyeongsang National UniversityJinjuRepublic of Korea
| | - Hobin Kang
- Division of Applied Life Science (BK21 Four Program)Plant Molecular Biology and Biotechnology Research CenterGyeongsang National UniversityJinjuRepublic of Korea
| | - Geon Hui Son
- Division of Applied Life Science (BK21 Four Program)Plant Molecular Biology and Biotechnology Research CenterGyeongsang National UniversityJinjuRepublic of Korea
| | - Jae‐Yean Kim
- Division of Applied Life Science (BK21 Four Program)Plant Molecular Biology and Biotechnology Research CenterGyeongsang National UniversityJinjuRepublic of Korea
- Division of Life ScienceGyeongsang National UniversityJinjuRepublic of Korea
| | - Sang Hee Kim
- Division of Applied Life Science (BK21 Four Program)Plant Molecular Biology and Biotechnology Research CenterGyeongsang National UniversityJinjuRepublic of Korea
- Division of Life ScienceGyeongsang National UniversityJinjuRepublic of Korea
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