RhAG Gene Suppression Increases Petal Number in Rose

Flower development is regulated by a broad range of stimuli. It is also well known that temperature plays a key role in controlling flowering time. However, the mechanisms of how temperature regulates flowering remain unknown. Nan Ma of China Agricultural University, together with colleagues, studied how low temperature significantly increases petal number in rose (Rosa hybrida).

Analysis revealed that the expression pattern of RhAG, a homolog of the Arabidopsis thaliana AGAMOUS C-function gene, is associated with flower development. Silencing of RhAG mimicked the effect of low temperature on petal development by increasing petal number through an increased production of petaloid stamens.

Analysis of DNA methylation level showed that low temperature treatment enhances the methylation level of the RhAG promoter, impeding its expression. This suggests that DNA methylation contributes to the modulation of RhAG expression.

RhAG plays an essential role in rose flowering by regulating petal development and that low temperatures increase petal number partly by suppressing RhAG expression via hypermethylation of the RhAG promoter.

For more on the study, read the article on BMC Plant Biology.