title: Arabidopsis heterotrimeric G-proteins play a critical role in host and nonhost resistance against Pseudomonas syringae pathogens.
abstract: Heterotrimeric G-proteins have been proposed to be involved in many aspects of plant disease resistance but their precise role in mediating nonhost disease resistance is not well understood. We evaluated the roles of specific subunits of heterotrimeric G-proteins using knock-out mutants of Arabidopsis Gα, Gβ and Gγ subunits in response to host and nonhost Pseudomonas pathogens. Plants lacking functional Gα, Gβ and Gγ1Gγ2 proteins displayed enhanced bacterial growth and disease susceptibility in response to host and nonhost pathogens. Mutations of single Gγ subunits Gγ1, Gγ2 and Gγ3 did not alter bacterial disease resistance. Some specificity of subunit usage was observed when comparing host pathogen versus nonhost pathogen. Overexpression of both Gα and Gβ led to reduced bacterial multiplication of nonhost pathogen P. syringae pv. tabaci whereas overexpression of Gβ, but not of Gα, resulted in reduced bacterial growth of host pathogen P. syringae pv. maculicola, compared to wild-type Col-0. Moreover, the regulation of stomatal aperture by bacterial pathogens was altered in Gα and Gβ mutants but not in any of the single or double Gγ mutants. Taken together, these data substantiate the critical role of heterotrimeric G-proteins in plant innate immunity and stomatal modulation in response to P. syringae.
authors.affiliation: The Samuel Roberts Noble Foundation, Plant Biology Division, Ardmore, Oklahoma, United States of America.
authors.forename: Seonghee
authors.initials: S
authors.lastname: Lee
authors.affiliation: The Samuel Roberts Noble Foundation, Plant Biology Division, Ardmore, Oklahoma, United States of America.
authors.forename: Clemencia M
authors.initials: CM
authors.lastname: Rojas
authors.affiliation: The Samuel Roberts Noble Foundation, Plant Biology Division, Ardmore, Oklahoma, United States of America.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Ishiga
authors.affiliation: Donald Danforth Plant Science Center, St. Louis, Missouri, United States of America.
authors.forename: Sona
authors.initials: S
authors.lastname: Pandey
authors.affiliation: The Samuel Roberts Noble Foundation, Plant Biology Division, Ardmore, Oklahoma, United States of America.
authors.forename: Kirankumar S
authors.initials: KS
authors.lastname: Mysore
mesh_terms: D017360:Arabidopsis / Q000382:microbiology* / Q000502:physiology*; D016000:Cluster Analysis; D060467:Disease Resistance / Q000235:genetics / Q000276:immunology; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D020962:Heterotrimeric GTP-Binding Proteins / Q000737:chemistry / Q000235:genetics*; D054884:Host-Pathogen Interactions; D009154:Mutation; D010641:Phenotype; D010935:Plant Diseases / Q000235:genetics* / Q000276:immunology* / Q000382:microbiology; D055503:Protein Multimerization; D021122:Protein Subunits / Q000737:chemistry / Q000235:genetics; D044224:Pseudomonas syringae / Q000276:immunology / Q000472:pathogenicity
chemical_list: D021122:Protein Subunits; D020962:Heterotrimeric GTP-Binding Proteins