影响马铃薯块茎低温糖化的植物激素相关基因的表达

Expression analysis of potato cold-induced sweetening related genes in phytohormone pathway

对低温贮藏5 d的低温糖化不敏感品种‘华薯三号’和敏感品种‘中薯五号’马铃薯块茎进行转录组测序,通过对差异表达基因的生物信息学分析,获得与植物激素相关的差异表达基因,其中6个与植物激素合成或信号转导有关的差异表达基因与糖分解代谢密切相关。结果表明:KOox2和GA3ox1是马铃薯块茎中赤霉素合成的关键酶基因,赤霉素可刺激淀粉酶和转化酶活性,加剧块茎还原糖的积累,是马铃薯低温糖化的正调控因子;ANT和AIL6属于参与乙烯响应的AP2转录因子家族;BRI1和BKI1是油菜素内酯信号通路中的转录因子,两者互作共同拮抗14–3–3蛋白质活性;ANT、AIL6、BRI1和BKI1这4个转录因子通过负调控转化酶基因的表达而影响还原糖的产生,是马铃薯低温糖化的负调控因子。

Differentially expressed genes(DEGs)associated with phytohormone pathway were analyzed by transcriptome sequencing in potato tubers stored at low temperature for 5d,which from potato insensitive cultivar(‘Huashu3’)and sensitive one(‘Zhongshu5’)to cold-induced sweetening(CIS).Six DEGs closely associated with sugar metabolism were screened from DEGs in phytohormone pathway related with phytohormone synthesis and signal transduction through bioinformatics analysis.And then the effects of these 6 DEGs on potato CIS were analyzed.The results were as follows:KOox2 and GA3ox1 are the key enzyme genes for gibberellin(GA)biosynthesis in potato tubers.GA could stimulate the activities of amylase and invertase,and increase the accumulation of reducing sugar in tuber.Thus GA was a positive regulator of potato CIS.ANT and AIL6 belong to AP2 transcription factor family involved in ethylene response.BRI1 and BKI1 are two transcription factors in brassinosteroid(BR)signaling pathway,and they could interact and then antagonize the activity of 14-3-3 protein.These 4 transcription factors ANT,AIL6,BRI1 and BKI1 affected the reducing sugar production through negative regulation of invertase gene expression,thus were negative regulators for potato CIS.