甜瓜果实发育相关SWEET糖转运蛋白基因的鉴定与功能初步分析

Identification and preliminary functional characterization of SWEET sugar transporters involved in fruit development of melon(Cucumis melo L.)

甜瓜是我国,也是世界上最重要的夏令水果之一。甜瓜果实内所含碳水化合物的种类和数量很大程度上决定其品质和产量。SWEET(sugars will eventually be exported transporters)糖转运蛋白具有运输葡萄糖和其他寡糖的功能,最近研究表明,SWEET糖转运蛋白在果实发育中可能起调控作用。本研究从甜瓜基因组中鉴定获得18个SWEETs糖转运蛋白基因,进一步通过RT-PCR并结合实时荧光定量PCR(quantitative real-time PCR,qPCR)方法,筛选到3个SWEETs基因在整个果实发育期内或某个发育时期表达量较高。亚细胞定位显示,两个SWEETs基因(CmSWEET3,CmSWEET7a)定位在细胞膜上。进一步通过酵母表达发现,甜瓜CmSWEET7a在体外具有转运葡萄糖和果糖的功能。本研究为揭示SWEET糖转运蛋白在甜瓜果实发育过程的调控作用奠定了基础。

Melon(Cucumis melo L.)is one of the most important summer fruits in China and worldwide.The quality and yield of melon fruits are largely determined by the types and amounts of carbohydrates contained in the fruits.SWEET(sugars will eventually be exported transporters)are a new class of proteins with the ability to transport glucose and other oligosaccharides,and recent studies have shown that SWEET sugar transporters may play a role in regulating the fruit development.In this study,18 SWEETs genes were identified from the melon genome,and further through RT-PCR combined with quantitative real-time PCR(qPCR)methods,three SWEETs genes with high expression level were identified during the whole or certain period of fruit development stages.Subcellular localization showed that two SWEETs genes(CmSWEET3,CmSWEET7a)were localized on the cell membrane.Further cloned into a yeast vector system,it was found that CmSWEET7a has the function of transporting glucose and fructose in vitro.This study laid the foundation for revealing the regulatory role of SWEET in the development process of melon fruit.