title: Heterotrimeric G-proteins facilitate resistance to plant pathogenic viruses in Arabidopsis thaliana (L.) Heynh.
abstract: Heterotrimeric G-proteins, consisting of Gα, Gβ and Gγ subunits, are important signal transducers in eukaryotes. In plants, G-protein-mediated signaling contributes to defense against a range of fungal and bacterial pathogens. Here we studied response of G-protein-deficient mutants to ssRNA viruses representing 2 different families: Cucumber mosaic virus (CMV) (Bromoviridae) and Turnip mosaic virus (TuMV) (Potyviridae). We found that development of spreading necrosis on infected plants was suppressed in the Gβ-deficient mutant (agb1-2) compared to wild type and Gα-deficient mutant (gpa1-4). In accordance, ion leakage caused by viral infection was also significantly reduced in agb1-2 compared to wild type and gpa1-4. Nevertheless, both viruses replicated better in agb1-2 plants, while gpa1-4 was similar to wild type. Analysis of pathogenesis-related genes showed that Gβ negatively regulated salicylic acid, jasmonic acid and abscisic acid marker genes during CMV and TuMV infections. Interestingly, analysis of salicylic acid deficient transgenic plants indicated that salicylic acid did not affect resistance against these viruses and did not influence the Gβ-mediated defense response. We conclude that heterotrimeric G-proteins play a positive role in defense against viral pathogens probably by promoting cell death.
authors.affiliation: a Plant Genetic Engineering Laboratory, School of Agriculture and Food Sciences, The University of Queensland , Brisbane , Queensland , Australia.
authors.forename: Eric
authors.initials: E
authors.lastname: Brenya
authors.affiliation: a Plant Genetic Engineering Laboratory, School of Agriculture and Food Sciences, The University of Queensland , Brisbane , Queensland , Australia.
authors.forename: Yuri
authors.initials: Y
authors.lastname: Trusov
authors.affiliation: b Queensland Alliance for Agriculture and Food Innovation, The University of Queensland , Brisbane , Queensland , Australia.
authors.forename: Ralf Georg
authors.initials: RG
authors.lastname: Dietzgen
authors.affiliation: a Plant Genetic Engineering Laboratory, School of Agriculture and Food Sciences, The University of Queensland , Brisbane , Queensland , Australia.
authors.forename: José Ramón
authors.initials: JR
authors.lastname: Botella
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism* / Q000821:virology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D017799:Cucumovirus / Q000472:pathogenicity; D044385:GTP-Binding Protein alpha Subunits / Q000235:genetics / Q000378:metabolism; D044387:GTP-Binding Protein beta Subunits / Q000235:genetics / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D020962:Heterotrimeric GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D017806:Tymovirus / Q000472:pathogenicity
chemical_list: D029681:Arabidopsis Proteins; D044385:GTP-Binding Protein alpha Subunits; D044387:GTP-Binding Protein beta Subunits; D020962:Heterotrimeric GTP-Binding Proteins
keywords: Cucumber mosaic virus (CMV); Heterotrimeric G-proteins; Turnip mosaic virus (TuMV); agb1; gpa1; plant defense; programmed cell death; salicylic acid; ssRNA viruses