Heterotrimeric G proteins facilitate arabidopsis resistance to necrotrophic pathogens and are involved in jasmonate signaling

Yuri Trusov, James Edward Rookes, David Chakravorty, David Armour, Peer Martin Schenk, José Ramón Botella

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149 Scopus citations

Abstract

Heterotrimeric G proteinshave been previously linked to plant defense; however a role for the Gβγ dimer in defense signaling has not been described to date. Using available Arabidopsis (Arabidopsis thaliana) mutants lacking functional Gaα or Gβ subunits, we show that defense against the necrotrophic pathogens Alternaria brassicicola and Fusarium oxysporum is impaired in Gβ-deficient mutants while Gα-deficient mutants show slightly increased resistance compared to wild-type Columbia ecotype plants. In contrast, responses to virulent (DC3000) and avirulent (JL1065) strains of Pseudomonas syringae appear to be independent of heterotrimeric G proteins. The induction of a number of defense-related genes in Gβ-deficient mutants were severely reduced in response to A. brassicicola infection. In addition, Gβ-deficient mutants exhibit decreased sensitivity to a number of methyl jasmonate-induced responses such as induction of the plant defensin gene PDF1.2, inhibition of root elongation, seed germination, and growth of plants in sublethal concentrations of methyl jasmonate. In all cases, the behavior of the Gα-deficient mutants is coherent with the classic heterotrimeric mechanism of action, indicating that jasmonic acid signaling is influenced by the Gβγ functional subunit but not by Gα. We hypothesize that Gβγ acts as a direct or indirect enhancer of the jasmonate signaling pathway in plants.

Original languageEnglish (US)
Pages (from-to)210-220
Number of pages11
JournalPlant physiology
Volume140
Issue number1
DOIs
Publication statusPublished - Jan 1 2006

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All Science Journal Classification (ASJC) codes

  • Physiology
  • Genetics
  • Plant Science

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