Cloning and Expression Dynamics of NCED and CYP707A Genes from Zoysia japonica Seeds

ABA is a major plant hormone inhibiting seed germination.Both 9-cis-epoxycarotenoid dioxygenase(NCED) and ABA 8'-hydroxylase(CYP707A) are key genes involved in the biosynthesis and degradation processes of ABA.Correlation of seed germination rate and these two genes has been reported in many plant species,but few in herbage seeds.Two herbage seeds from Zoysia japonica-Haiqing1(H1) and wild type(WT) were used to study the relationship between seed germination rate and the expressions of these two genes.The gene CYP707A was cloned and the expression of both NCED and CYP707A in different materials under different imbibition regimes were determined through Real-time PCR.Both NCED and CYP707A had a continuous increasing trend in H1 with seed imbibition processing and had a relatively higher germination rate.However,the expressions of these two genes in WT with seed imbibition processing showed an increasing trend during the first 2 hours of imbibition then dropped to a very low level.The expression variances of these two genes suggest that there was a mutual coordination and balance relationship between ABA biosynthesis and degradation during seed germination.