过表达MtVP1对马铃薯表型及糖代谢的影响

Effects of Overexpression of MtVP1 on Potato Phenotypes and Sugar Metabolism

I型H^(+)-PPase参与糖异生和蔗糖分解代谢,利用不同的糖(蔗糖、葡萄糖和果糖)饲喂拟南芥(Arabidopsis thaliana)Ⅰ型H^(+)-PPase基因不同类型的突变体,产生的表型不一致,因此,推测Ⅰ型H^(+)-PPase可能存在其它影响糖代谢的机制。为进一步明确该酶对糖代谢的影响,以过表达MtVP1的马铃薯(Solanum tuberosum)渭薯4号为研究对象,观察不同培养条件下的表型,监测糖含量变化,并利用转录组测序分析转录谱。结果表明,过表达MtVP1马铃薯表现出红色茎、紫色花和表皮毛更发达,单株块茎数减少,块茎变大,块茎皱缩速度加快;转基因马铃薯块茎中淀粉、葡萄糖和果糖含量显著下降,芽中葡萄糖和果糖含量也显著下降。果糖饲喂导致转基因马铃薯花青素含量显著降低;转基因马铃薯体内果糖-1,6-二磷酸酶和果糖-2,6-二磷酸酶基因表达上调3–7倍。研究结果为进一步从糖代谢角度探究Ⅰ型H^(+)-PPase的生理功能提供参考。

TypeⅠH^(+)-PPase is involved in gluconeogenesis and sucrose catabolism.Different types of mutants of Arabidopsis thaliana typeⅠH^(+)-PPase gene fed with different sugars(sucrose,glucose and fructose)showed various phenotypes.Therefore,it is speculated that type I H^(+)-PPase may contain other mechanisms that affect sugar metabolism.In order to further clarify the effect of the enzyme on sugar metabolism,phenotypes of the MtVP1 overexpressed potato Weishu 4 were observed under different culture conditions.The fluctuation of sugar content was monitored,and the transcription profile was analyzed.The results showed that the Mt VP1 overexpressed potato grew red stem,purple flower,and more developed trichomes.Furthermore,tubers per plant decreased in number,but became larger in size,and shriveled up faster.However,the transgenic plant had significantly decreased starch,glucose,and fructose contents in tubers,and glucose and fructose contents in buds.At the same time,feeding fructose significantly reduced the anthocyanin,and up-regulated the gene expression of fructose-1,6-diphosphate and fructose-2,6-diphosphate by 3–7 fold in the transgenic potato.The results could shed light on further studies of the physiological function of type I H^(+)-PPase from the perspective of sugar metabolism.