Genome-Wide Identification of Petunia Genes and Potential Function of in Benzenoid/Phenylpropanoid Biosynthesis.

Volatile benzenoids/phenylpropanoids are the main flower scent compounds in petunia (). Heat shock factors (HSFs), well known as the main regulator of heat stress response, have been found to be involved in the biosynthesis of benzenoid/phenylpropanoid and other secondary metabolites. In order to figure out the potential function of HSFs in the regulation of floral scent in petunia, we systematically identified the genome-wide petunia genes and analyzed their expression and then the interaction between the key petunia gene with target gene involved in benzenoid/phenylpropanoid biosynthesis. The results revealed that 34 gene family members were obtained in petunia, and most petunia contained one intron. The phylogenetic analysis showed that 23 petunia HSFs were grouped into the largest subfamily HSFA, while only two petunia HSFs were in HSFC subfamily. The DBD domain and NLS motif were well conserved in most petunia HSFs. Most petunia genes' promoters contained STRE motifs, the highest number of -acting element. is highly expressed in petal tubes, followed by peduncles and petal limbs. During flower development, the expression level of was dramatically higher at earlier flower opening stages than that at the bud stage, suggesting that may have potential roles in regulating benzenoid/phenylpropanoid biosynthesis. The expression pattern of is positively related with , which catalyzes the first committed step in the phenylpropanoid pathway. In addition, there are three STRE elements in the promoter of . was proven to positively regulate the expression of according to the yeast one hybrid and dual luciferase assays. These results lay a theoretical foundation for further studies of the regulation of HSFs on plant flower scent biosynthesis.