PpMADS2与PpMADS3协同调控黄肉桃果实类胡萝卜素积累机制的研究

Mechanism of PpMADS2 and PpMADS3 Synergistically Regulating Carotenoids Accumulation in Peach Fruit

为探究黄肉桃果实中MADS-box家族转录因子对类胡萝卜素代谢的调控作用,从黄肉桃果实中克隆得到两个MADS基因,分别命名为Pp MADS2(PRUPE_5G208500)和Pp MADS3(PRUPE_5G208400)。PpMADS2开放阅读框为768bp,编码255个氨基酸;PpMADS3开放阅读框为756bp,编码251个氨基酸。生物信息分析显示二者蛋白的N端均含有MADS-box家族典型的特征结构域。亚细胞定位分析显示PpMADS2和PpMADS3定位于细胞核。荧光定量PCR结果表明PpMADS2、Pp MADS3以及类胡萝卜素合成基因PpPSY和PpCHYB在黄肉桃果实成熟过程中表达量呈上升趋势,与果实成熟期间类胡萝卜素的含量增加一致。酵母双杂交试验结果表明PpMADS2和PpMADS3蛋白存在相互作用。双荧光素酶试验结果表明PpMADS2和PpMADS3可以协同激活PpPSY和PpCHYB启动子。因此推测PpMADS2和PpMADS3可通过转录激活PpPSY和PpCHYB促进桃果实类胡萝卜素的积累。

To explore the regulation of MADS-box family transcription factors on carotenoid metabolism in yellow fleshed peach,two MADS genes named as PpMADS2(PRUPE_5G208500)and PpMADS3(PRUPE_5G208400)were cloned.The open reading frames of PpMADS2 and PpMADS3 were 768 bp and 756 bp,encoding 255 and 251 amino acids,respectively.Bioinformatics analysis revealed that the N-terminus of both proteins contained typical characteristic domains of MADS-box family.Subcellular localization showed that both PpMADS2 and PpMADS3 were located at the nucleus.The results showed the gene expression levels of PpMADS2,PpMADS3 as well as carotenoid biosynthetic genes such as PpPSY and PpCHYB increased during fruit ripening,which was consistent with the carotenoid accumulation in yellow fleshed peach.Furthermore,the results demonstrated that PpMADS2 could interact with PpMADS3 then synergistically activate the promoters of PpPSY and PpCHYB genes.Therefore,it is speculated that PpMADS2 and PpMADS3 promoted the accumulation of carotenoids in yellow fleshed peach fruit cooperatively through transcriptional activation of PpPSY and PpCHYB.These research provided a theoretical basis for further exploring the regulatory mechanism of MADS-box transcription factors on carotenoid accumulation in peach fruit.