基于转录组测序挖掘马铃薯块茎采后发芽关键基因

Identification of Critical Genes Involved in Postharvest Sprouting of Potato Tubers Based on RNA-seq Analysis

马铃薯是全球第4大粮食作物,营养丰富.然而,马铃薯块茎采后发芽显著影响其商品价值和种薯质量.该研究结合表型观察、细胞学分析、生理生化检测、植物激素含量测定、Marker基因表达分析等,明确了马铃薯采后发芽的关键时期.通过对马铃薯块茎采后发芽关键时期样本进行RNA-seq分析,挖掘了马铃薯块茎采后发芽关键基因.结果表明‘费乌瑞它’马铃薯块茎采后休眠解除期为30 d,芽生长期为45 d.从休眠期到休眠解除期和休眠解除期到芽生长期分别有1008个基因(252个上调、756个下调)和4576个基因(2800个上调、1696个下调)表达量发生显著变化.156个转录因子基因(主要属于AP2、MYB和bHLH家族)及植物激素(ABA与GA)合成、代谢、信号转导相关基因,如NCED4,ZEP,KS,KO2,ABI5等.这些差异表达基因主要富集在苯丙烷生物合成(ko00940)、苯丙氨酸代谢(ko00360)、类胡萝卜素生物合成(ko00100)、DNA复制(ko03030)、糖代谢(ko00520)等通路.

The potato is the fourth main food crops worldwide with high nutritional value.However,potato tuber postharvest sprouting significantly affects the quality of product and seed potatoes.Through phenotype observation,comparison of the histological structures,analysis of physiological and biochemical indexes,measurement of contents of phytohormones,and monitoring of the marker gene expression,we confirmed the three main transition stages of postharvest sprouting including dormancy,dormancy releasing,and bud growth.Additionally,RNA-seq was performed to identify the critical genes involved in potato tuber sprouting.The results exhibited that the time points of tuber dormancy releasing and bud growth were at 30 d and 45 d after postharvest,respectively.During tuber dormancy to dormancy releasing,expression levels of 1008 genes(252 upregulated and 756 downregulated)were significantly changed.During dormancy releasing to bud growth,4576 genes differentially expressed(DE),including 2800 upregulated and 1696 downregulated.Among these DE genes,expressions of 156 transcription factor(TF)genes were greatly changed,most of these TFs belonging to AP2,MYB,and bHLH TF families.Meanwhile,several genes participated in ABA and GA biosynthesis,metabolism,and signaling,also observably changed their expression levels,such as NCED4,ZEP,KS KO2,ABI5,etc.KEEG enrichment analysis showed that those DE genes mainly enriched in the pathways of phenylpropanoid biosynthesis(ko00940),phenylalanine metabolism(ko00360),carotenoid biosynthesis(ko00100),etc.