Characterization of a fertility-related SANT/MYB gene (PhRL) from petunia

Abstract The SANT/MYB transcription factors play a critical role in regulating the development of plants. Recently, various SANT/MYB transcription factors have been reported in some plant species, while none in petunia. In this research, a gene containing the SANT/MYB region, designated as PhRL , was firstly identified in petunia flower buds cDNA library. The open-reading frame of PhRL was 288 bp, encoding a putative 10.97 kDa protein of 95 amino acids. Sequence alignment exhibited that PhRL contained a high conserved SANT/MYB domain. Phylogenetic comparison showed that PhRL was clustered together with AtRL5 and AtRL6 of Arabidopsis . Different from the reported SANT/MYB transcription factors, PhRL was preponderantly expressed in the anther and then in the pistil, with little/no detection in sepal, petal, stem, root or leaf. RNA interference (RNAi) of the PhRL expression in petunia showed significant decrease in pollen viability, and enlargement in size of sex organs. These results indicated that PhRL was a fertility-related gene, which might be involved in both the anther and pistil development of petunia. Studies on PhRL may further our understanding of the molecular mechanisms of sex organs development in petunia.