Photoperiod Effected on Indole-3-acetic Acid Synthase Genes Expression of Beta Vulgaris

The phytohormone auxin drives plants growth, development and the transformation of morphogenesis. Indole-3-acetic acid (IAA) has been identified as the major auxin in plant species increasingly and the evolutionary biosynthesis pathway of IAA was conserved in the plant kingdom. Sugar beet (Beta vulgaris) is an important crop plant that accounts for 30% of the world’s sugar production annually. Ten IAA synthetic genes such as BvAMI1, BvNIT4, Bv22D, BvIAA6, BvIAA8, BvIAA9, BvIAA13, BvIAA26, BvIAA29 and BvIAA33 were explored whose expression played critical roles in rate-limiting step of the IAA synthesis pathway in Sugar beet. Moreover the expression patterns of these genes were investigated by qRT-PCR and the IAA concentration was quantified by UPLC-MS/MS in leaves of different time points and photoperiods in order to find out the mechanism that how IAA regulated plant development under different photoperiods. These results demonstrated that BvIAA6, BvIAA9, BvIAA13, BvIAA26, BvIAA33 and Bv22D genes significantly expressed different in leaves between the long day(16h) and short day(8h), which were consistanted with the contents of IAA by UPLC/MS/MS. Collecttively, our data provided a different angle for analyzing and understanding the molecular mechanisms between photoperiods and the synthesis of IAA during plant development.