猕猴桃后熟过程中ABA响应结合因子AcAREB1调控AcGH3.1的表达

Studies on AcAREB1 Regulating the Expression of AcGH3.1 During Postharvest Ripening of Kiwifruit

以‘红阳’猕猴桃为试材,研究脱落酸(ABA)对果实采后成熟过程中生长素(IAA)代谢的影响。结果表明,外源ABA处理能够加速自由态IAA的降解,提高IAA-Asp含量,同时可以显著促进IAA降解相关基因AcGH3.1的表达。从猕猴桃基因组数据库中分离鉴定到5个ABA响应结合因子基因(AcAREB1~AcAREB5),荧光定量PCR显示,5个基因在果实采后成熟过程中均能不同程度响应ABA。酵母单杂交结果显示,AcAREB1能够直接结合到AcGH3.1的启动子上。亚细胞定位显示AcAREB1定位在细胞核上。酵母自激活试验表明AcAREB1具有转录激活活性。这些结果表明,在猕猴桃果实成熟过程中,AcAREB1可以响应ABA,调控AcGH3.1的表达,从而促进IAA的降解,最终使得果实开始软化成熟。

The effect of ABA on IAA metabolism during postharvest ripening of‘Hongyang’kiwifruit were studied.The results showed that exogenous ABA treatment could accelerate the degradation of free IAA,increase the content of IAA-Asp,and significantly promote the expression of IAA degradation related gene AcGH3.1.Five ABA-responsive binding factor genes(AcAREB1–AcAREB5)were isolated and identified from kiwifruit genome database.qRT-PCR showed that all five AcAREB genes could respond to ABA during postharvest ripening.Yeast one-hybrid results showed that AcAREB1 could directly bind to the AcGH3.1 gene promoter.Subcellular localization assay showed that AcAREB1 was located on the nucleus.Yeast self-activation experiments proved that AcAREB1 was a transcription factor with transcriptional activation activity.These results indicate that AcAREB1 can regulate the expression of AcGH3.1 gene corresponding to ABA during the ripening process of kiwifruit,thereby promoting the degradation of IAA,and finally leading to fruit softening and ripening.