CHARACTERIZATION OF 9-CIS-EPOXYCAROTENOID DIOXYGENASE3 GENE FROM Hevea brasiliensis AND ITS EXPRESSION RESPONSES BY TISSUE TYPE DURING DROUGHT STRESS

Abstract

In higher plants, the first committed step in controlling abscisic acid (ABA) biosynthesis, 9-Cis-Epoxycarotenoid Dioxygenase (NCED) is an important rate-limiting enzyme. It plays a major role in plant response to drought stress in stomatal aperture regulation. In this study, the 1,785bp full-length cDNA (designated as HbNCED3), has an open reading frame of 595 encoded amino acids. Amino acid sequence alignment showed that HbNCED3 shares more than 80% similarity with NCED3 from Manihot esculenta and Jatropha curcas. The quantitative real-time PCR (qPCR) was used for detecting the transcription level of HbNCED3 gene after withholding water for 0, 3, 5, 7, 9 and 11 days. The NCED3 gene was expressed in all tested tissues with different response patterns. The HbNCED3 expression level in root increased sharply during the early stages of drought stress. The continuous accumulation of ABA in leaves was caused mainly by increased transcription of HbNCED3 in the root. This suggested the HbNCED3 may play a role in the molecular drought stress of rubber tree and would serve as a guide for future follow‐up research on drought stress mechanism in Hevea.