Loss-of-function mutations in the Arabidopsis heterotrimeric G-protein α subunit enhance the developmental defects of brassinosteroid signaling and biosynthesis mutants

Yajun Gao, Shucai Wang, Tadao Asami, Jin Gui Chen

Research output: Contribution to journalArticlepeer-review

41 Scopus citations

Abstract

Loss-of-function alleles of the sole heterotrimeric G-protein α subunit in Arabidopsis, GPA1, display defects in cell proliferation throughout plant development. Previous studies indicated that GPA1 is involved in brassinosteroid (BR) response. Here we provide genetic evidence that loss-of-function mutations in GPA1, gpa1-2 and gpa1-4, enhance the developmental defects of bri1-5, a weak allele of a BR receptor mutant, and det2-1, a BR-deficient mutant in Arabidopsis. gpa1-2 bri1-5 and gpa1-4 det2-1 double mutants had shorter hypocotyls, shorter roots and fewer lateral roots, and displayed more severe dwarfism than bri1-5 and det2-1 single mutants, respectively. By using the Arabidopsis hypocotyl as a model system where the parameters of cell division and cell elongation can be simultaneously measured, we found that gpa1 can specifically enhance the cell division defects of bri1-5 and det2-1 mutants. Similarly, gpa1 specifically enhances cell division defects in the primary roots of bri1-5 and det2-1 mutants. Furthermore, an additive effect on cell division between gpa1 and bri1-5 or det2-1 mutations was observed in the hypocotyls, whereas a synergistic effect was observed in the roots. Taken together, these results provided the first genetic evidence that G-protein- and BR-mediated pathways may be converged to modulate cell proliferation in a cell/tissue-specific manner.

Original languageEnglish
Pages (from-to)1013-1024
Number of pages12
JournalPlant and Cell Physiology
Volume49
Issue number7
DOIs
StatePublished - Jul 2008
Externally publishedYes

Funding

Natural Sciences and Engineering Research Council of Canada and Canada Foundation for Innovation (to J.-G.C.)

Keywords

  • Arabidopsis
  • Brassinosteroid (BR)
  • Cell proliferation
  • Heterotrimeric G-protein α subunit (GPA1)
  • Hypocotyl
  • Root

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