过表达VvCYP707A1基因降低葡萄果肉中的ABA含量

Overexpression of ABA 8’-hydroxylase(VvCYP707A1)Gene Reduces ABA Content in Grape Pulp

植物中ABA (脱落酸)的含量取决于它的合成和分解代谢速度的快慢。CYP707A家族编码的ABA 8'-羟化酶是ABA代谢途径的关键酶。本研究以‘鄞红’葡萄果肉为材料,采用一步克隆技术构建过表达载体pCambia1302-VvCYP707A1,并对花蕾期葡萄花序进行转化,分析葡萄果肉中VvCYP707A1基因的过表达对内源ABA含量的影响。实时荧光定量PCR (RT-qPCR)结果显示,过熟期转基因葡萄果肉中VvCYP707A1基因的表达量显著高于野生型。进一步使用酶联免疫法(ELISA)测定相同条件下的ABA含量后发现,ABA含量显著低于野生型。这些结果表明,过表达VvCYP707A1基因降低了葡萄果肉中ABA含量,推测VvCYP707A1的表达是葡萄果肉中ABA代谢的主要调控机制。研究结果为ABA分解代谢机制提供一定理论依据。

In plants,the level of endogenous abscisic acid(ABA)is determined by its biosynthesis and catabolism.ABA 8'-hydroxylase is a key enzyme for ABA degradation during its catabolism that is encoded by the CYP707A family genes.In this study,we overexpressed ABA 8'-hydroxylase in the grape pulp by transforming the inflorescence of'Yinhong'grapes at the flower bud stage infiltrated with agrobacteria hosting a binary vector pCambia1302-VvCYP707A1 and then harvested the grapes after reaching the fruit mature stage to analyze both the expression level of the transformed VvCYP707A1 and the endogenous ABA content in the grape pulp.The results showed that in the transgenic grape pulp at the ripening stage the expression of VvCYP707A1 gene measured by Real-time quantitative PCR(qRT-PCR)was significantly higher than in the wild-type control.On the contrast,the ABA content assayed with the enzyme-linked immunoassay(ELISA)was significantly lower than in the wild-type control.Therefore,our results demonstrated that overexpression of the VvCYP707A1 gene has reduced the ABA content in grape pulp,implying that VvCYP707A1 has an important regulatory role on ABA metabolism in grape pulp.