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Dölfors F, Holmquist L, Tzelepis G, Dixelius C. Rhizoctonia solani Infection Assay of Young Sugar Beet and Arabidopsis plantlets. Bio Protoc 2022; 12:e4300. [DOI: 10.21769/bioprotoc.4300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 11/11/2021] [Accepted: 11/22/2021] [Indexed: 11/02/2022] Open
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Tzelepis G, Dölfors F, Holmquist L, Dixelius C. Plant mitochondria and chloroplasts are targeted by the Rhizoctonia solani RsCRP1 effector. Biochem Biophys Res Commun 2021; 544:86-90. [PMID: 33550013 DOI: 10.1016/j.bbrc.2021.01.019] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 01/07/2021] [Indexed: 01/10/2023]
Abstract
The fungal species Rhizoctonia solani belongs to the Basidiomycota division and is a ubiquitous soil-borne pathogen. It is the main agent of the damping-off disease in seedlings and causes the root and crown rot disease in sugar beets. Plant pathogens deploy small secreted proteins, called effectors, to manipulate plant immunity in order to infect the host. Here, a gene (RsCRP1) encoded a putative effector cysteine-rich protein was cloned, expressed in Cercospora beticola and used for virulence assays. The RsCRP1 gene was highly induced upon the early-infection stage of sugar beet seedlings and disease was promoted. Confocal microscopy demonstrated localization to the chloroplasts and mitochondria upon transient expression of RsCRP1 in leaves of Nicotiana benthamiana. Further, this effector was unable to induce necrosis or to suppress hypersensitive response induced by the Avr4/Cf4 complex in N. benthamiana. Overall, these data indicate that RsCRP1 is a novel effector targeting distinct plant cell organelles in order to facilitate a successful infection at the early stages of the disease development.
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Affiliation(s)
- Georgios Tzelepis
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Uppsala Biocenter, Box 7026, SE-750 07, Uppsala, Sweden.
| | - Fredrik Dölfors
- Swedish University of Agricultural Sciences, Department of Plant Biology, Uppsala BioCenter, Linnean Center for Plant Biology, P.O. Box 7080, S-75007, Uppsala, Sweden
| | - Louise Holmquist
- MariboHilleshög Research AB, Säbyholmsvägen 24, S-26191, Landskrona, Sweden
| | - Christina Dixelius
- Swedish University of Agricultural Sciences, Department of Plant Biology, Uppsala BioCenter, Linnean Center for Plant Biology, P.O. Box 7080, S-75007, Uppsala, Sweden
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Charova SN, Dölfors F, Holmquist L, Moschou PN, Dixelius C, Tzelepis G. The RsRlpA Effector Is a Protease Inhibitor Promoting Rhizoctonia solani Virulence through Suppression of the Hypersensitive Response. Int J Mol Sci 2020; 21:ijms21218070. [PMID: 33138028 PMCID: PMC7662947 DOI: 10.3390/ijms21218070] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 10/23/2020] [Accepted: 10/27/2020] [Indexed: 01/11/2023] Open
Abstract
Rhizoctonia solani (Rs) is a soil-borne pathogen with a broad host range. This pathogen incites a wide range of disease symptoms. Knowledge regarding its infection process is fragmented, a typical feature for basidiomycetes. In this study, we aimed at identifying potential fungal effectors and their function. From a group of 11 predicted single gene effectors, a rare lipoprotein A (RsRlpA), from a strain attacking sugar beet was analyzed. The RsRlpA gene was highly induced upon early-stage infection of sugar beet seedlings, and heterologous expression in Cercospora beticola demonstrated involvement in virulence. It was also able to suppress the hypersensitive response (HR) induced by the Avr4/Cf4 complex in transgenic Nicotiana benthamiana plants and functioned as an active protease inhibitor able to suppress Reactive Oxygen Species (ROS) burst. This effector contains a double-psi beta-barrel (DPBB) fold domain, and a conserved serine at position 120 in the DPBB fold domain was found to be crucial for HR suppression. Overall, R. solani seems to be capable of inducing an initial biotrophic stage upon infection, suppressing basal immune responses, followed by a switch to necrotrophic growth. However, regulatory mechanisms between the different lifestyles are still unknown.
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Affiliation(s)
- Spyridoula N. Charova
- Institute of Molecular Biology and Biotechnology Foundation of Research and Technology-HELLAS, GR-70013 Heraklion, Crete, Greece; (S.N.C.); (P.N.M.)
- Department of Biology, University of Crete, Voutes University Campus, P.O. Box 2208, GR-70013 Heraklion, Crete, Greece
| | - Fredrik Dölfors
- Department of Plant Biology, Swedish University of Agricultural Sciences, Uppsala BioCenter, Linnean Center for Plant Biology, P.O. Box 7080, S-75007 Uppsala, Sweden; (F.D.); (C.D.)
| | - Louise Holmquist
- MariboHilleshög Research AB, Säbyholmsvägen 24, S-26191 Landskrona, Sweden;
| | - Panagiotis N. Moschou
- Institute of Molecular Biology and Biotechnology Foundation of Research and Technology-HELLAS, GR-70013 Heraklion, Crete, Greece; (S.N.C.); (P.N.M.)
- Department of Biology, University of Crete, Voutes University Campus, P.O. Box 2208, GR-70013 Heraklion, Crete, Greece
- Department of Plant Biology, Swedish University of Agricultural Sciences, Uppsala BioCenter, Linnean Center for Plant Biology, P.O. Box 7080, S-75007 Uppsala, Sweden; (F.D.); (C.D.)
| | - Christina Dixelius
- Department of Plant Biology, Swedish University of Agricultural Sciences, Uppsala BioCenter, Linnean Center for Plant Biology, P.O. Box 7080, S-75007 Uppsala, Sweden; (F.D.); (C.D.)
| | - Georgios Tzelepis
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Uppsala BioCenter, Box 7026, SE-750 07 Uppsala, Sweden
- Correspondence: ; Tel.: +46-18-67181503
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Holmquist L, Dölfors F, Fogelqvist J, Cohn J, Kraft T, Dixelius C. Major latex protein-like encoding genes contribute to Rhizoctonia solani defense responses in sugar beet. Mol Genet Genomics 2020; 296:155-164. [PMID: 33118051 PMCID: PMC7840631 DOI: 10.1007/s00438-020-01735-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 10/09/2020] [Indexed: 12/15/2022]
Abstract
Sugar beets are attacked by several pathogens that cause root damages. Rhizoctonia (Greek for “root killer”) is one of them. Rhizoctonia root rot has become an increasing problem for sugar beet production and to decrease yield losses agronomical measures are adopted. Here, two partially resistant and two susceptible sugar beet genotypes were used for transcriptome analysis to discover new defense genes to this fungal disease, information to be implemented in molecular resistance breeding. Among 217 transcripts with increased expression at 2 days post-infection (dpi), three resistance-like genes were found. These genes were not significantly elevated at 5 dpi, a time point when increased expression of three Bet v I/Major latex protein (MLP) homologous genes BvMLP1, BvMLP2 and BvML3 was observed in the partially resistant genotypes. Quantitative RT-PCR analysis on diseased sugar beet seedlings validated the activity of BvMLP1 and BvMLP3 observed in the transcriptome during challenge by R. solani. The three BvMLP genes were cloned and overexpressed in Arabidopsis thaliana to further dissect their individual contribution. Transgenic plants were also compared to T-DNA mutants of orthologous MLP genes. Plants overexpressing BvMLP1 and BvMLP3 showed significantly less infection whereas additive effects were seen on Atmlp1/Atmlp3 double mutants. The data suggest that BvMLP1 and BvMLP3 may contribute to the reduction of the Rhizoctonia root rot disease in sugar beet. Impact on the defense reaction from other differential expressed genes observed in the study is discussed.
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Affiliation(s)
- Louise Holmquist
- MariboHilleshög Research AB, Säbyholmsvägen 24, 26191, Landskrona, Sweden.,Department of Plant Biology, Uppsala BioCenter, Linnean Center for Plant Biology, Swedish University of Agricultural Sciences, P.O. Box 7080, 75007, Uppsala, Sweden
| | - Fredrik Dölfors
- Department of Plant Biology, Uppsala BioCenter, Linnean Center for Plant Biology, Swedish University of Agricultural Sciences, P.O. Box 7080, 75007, Uppsala, Sweden
| | - Johan Fogelqvist
- Department of Plant Biology, Uppsala BioCenter, Linnean Center for Plant Biology, Swedish University of Agricultural Sciences, P.O. Box 7080, 75007, Uppsala, Sweden
| | - Jonathan Cohn
- Syngenta, Crop Protection, 9 Davis Drive, Research Triangle Park, NC, 27709, USA
| | - Thomas Kraft
- MariboHilleshög Research AB, Säbyholmsvägen 24, 26191, Landskrona, Sweden
| | - Christina Dixelius
- Department of Plant Biology, Uppsala BioCenter, Linnean Center for Plant Biology, Swedish University of Agricultural Sciences, P.O. Box 7080, 75007, Uppsala, Sweden.
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