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- Title
The α-subunit of the heterotrimeric G-protein affects jasmonate responses in Arabidopsis thaliana.
- Authors
Okamoto, Haruko; Göbel, Cornelia; Capper, Richard G.; Saunders, Nigel; Feussner, Ivo; Knight, Marc R.
- Abstract
Heterotrimeric G-proteins have been implicated in having a role in many plant signalling pathways. To understand further the role of G-proteins, a preliminary experiment was performed to assess the impact of the Gα subunit loss-of-function mutation gpa1-1 on the Arabidopsis transcriptome. The analysis indicated that the Gα subunit may play a role in response to jasmonic acid (JA). Consistent with this, Gα mutants showed a reduced response to JA in inhibition of chlorophyll accumulation and root growth, whilst Gα gain-of-function plants overexpressing Gα showed the opposite phenotype. The levels of JA and related compounds were unaffected in the gpa1-1 mutant, as was autoregulation of the Allene Oxide Synthase (AOS) gene that encodes a key enzyme for JA biosynthesis. In contrast, further analyses using Gα loss- and gain-of-function Arabidopsis lines indicated that Gα positively modulates the expression of the Vegetative Storage Protein (VSP) gene. This indicates that the Gα subunit regulates a subset of JA-regulated genes defining a branch point in this signalling pathway in Arabidopsis. Further analysis of the impact of Gα loss of function upon the JA-regulated transcriptome using Arabidopsis full genome arrays indicated that up to 29% of genes that are >2-fold regulated by JA in the wild type are misregulated in the Gα mutant. This supports the observation that a significant proportion of, but not all, JA-regulated gene expression is mediated by Gα.
- Subjects
G proteins; ARABIDOPSIS thaliana; PLANT mutation; PLANT genomes; PLANT genetics
- Publication
Journal of Experimental Botany, 2009, Vol 60, Issue 7, p1991
- ISSN
0022-0957
- Publication type
Article
- DOI
10.1093/jxb/erp060