[Cloning and expression analysis on full length CDS of zeaxanthin epoxidase gene in Pseudostellaria heterophylla].

Zeaxanthin epoxidase plays an important role in indirect pathway of plant abscisic acid biosynthesis. According to the data of Pseudostellaria heterophylla transcriptome, zeaxanthin epoxidase gene was isolated and named as PhZEP. The results of bioinformatics analysis showed that the coding sequence of PhZEP was 1 263 bp long and encoded 420 amino acids. The putative protein molecular weight was 47.34 kDa and its theoretical isoelectric point was 6.64. The characteristic structure domains were predicted, including binding site of lipoprotein and flavoprotein monooxyenase. A signal peptide was discovered at the N-terminal of amino acids. The Real-time PCR revealed that PhZEP had a higher expression level in leaves than other tissues of P.heterophylla. Highly expressed PhZEP was also observed at 10 d and 40 d tuberous root after flowering. PhZEP presented a different expression after treatment with ABA, fluridone and ABA +fluridone compared to the control. The expression of PhZEP in tuberous root after ABA treatment was close to that in control group, while PhZEP showed significant up-regulation in the fluridone treatment group. In this study, the PhZEP gene from P. heterophylla was cloned and this result has important significance for its functional identification. This research provides a basis for the further analysis on functional mechanism of ABA during development of P. heterophylla.