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 language | English |
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Pages (from-to) | 1013-1024 |
Number of pages | 12 |
Journal | Plant and Cell Physiology |
Volume | 49 |
Issue number | 7 |
DOIs | |
State | Published - Jul 2008 |
Externally published | Yes |
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