Abstract
Gibberellin signaling pathway is composed of a negative regulator, Slender rice 1 (SLR1) and its degradation system via ubiquitin-26S proteasome pathway. We investigated a point of action which rice heterotrimeric G protein α subunit (RGA1) may concern is a regulation of SLR1 activity or its degradation system.
We identified that an approx. 75kDa protein recognized by anti-SLR1 antibody specifically accumulated in normal cultivars, not in RGA1 deficient mutants, d1 , under the dark condition at 30 degrees centigrade. The amount of the protein is decreased after application of gibberellin, in parallel to a response of SLR1, approx.70kDa. This result suggests that an approx. 75kDa protein is SLR1 post-translationally modified or SLR1 relative. An antibody against O-GlcNAc recognized an approx. 75kDa protein in normal cultivars, not in d1 . This observation suggests that RGA1 controls the accumulation of post-translationally modified SLR1 or SLR1 relative.
