Identification Of A BAHD Acyltransferase Involved In Terpenoid And Salt Tolerance In Arabidopsis

BAHD acyltransferases are involved in the synthesis and elaboration of a wide variety of secondary metabolites, such as shikimic acid-phenylpropanoid derivatives, alkaloids, terpenoids, polyamine, short and medium chain fatty alcohol. Our previous studies have shown that a novel BAHD family acyltransferase gene may play a role in salt tolerance and terpenoid synthesis pathway in Arabidopsis. Terpenoid is very important in many aspects of plant development and physiological processes, such as photosynthesis and grows and development. We identified VAT25, a BAHD acyltransferase-like gene, which played a possible role in maintaining terpenoid synthesis pathway to regulate salt tolerance in Arabidopsis. The main results are as follows:1. VAT25belongs to the BAHD acyltransferase gene family. The BAHD family can be classified into five clades through phylogenetic analysis, and VAT25is a member of clade Ⅲ. VAT25has these two motifs:the sequence HRLADA and CFGWG. The expression of VAT25-promoter::GUS and qRT-PCR were observed specifically in roots。2. Overexpression of VAT25resulted in a BR deficient phenotype, and application of BR restored normal growth in dwarf mutants. The result suggested that VAT25function in levels of BRs, and VAT25played a possible role in maintaining BR homeostasis.3. Loss-of-function analyses shown that the VAT25T-DNA mutant and microRNA mutant plants were both partially hypersensitive to exogenous and exhibited an increased endogenous levels of ABA. Meanwhile, the VAT25T-DNA mutant and microRNA mutant plants were insensitive to high-salinity stress (high concentration of NaCl and KCl) during the growth phase. Moreover, salt tolerance arose from enhanced ABA accumulation in the knockout mutants.4. VAT25and terpenoid biosynthesis genes PEN1were coexpressing in salt and ABA stress to some extent. These observations suggest that VAT25may regulate terpenoid synthesis pathway to mediate salt stress tolerance in Arabidopsis.