淀粉是马铃薯重要的品质性状之一，广泛应用于食品、医药、石油化工等行业，市场上对高淀粉马铃薯品种的需求逐年提高。为探究马铃薯块茎淀粉积累特性及调控的关键基因，本研究通过RNA测序分析，分别对高、低淀粉含量马铃薯品种大西洋(DXY)、定薯1号(DS1)的匍匐茎(a)、块茎膨大前期(b)、块茎膨大中期(c)、块茎膨大后期(d)及成熟期(e)进行转录组谱分析，5个时期共获得9494个差异表达基因(DEGs)，结合功能注释发现差异基因主要富集在结合绑定和催化活性等分子功能中，代谢通路分析发现差异基因主要富集在碳水化合物途径中，其中有137个DEGs与淀粉和蔗糖代谢相关。筛选获得9个调控淀粉合成关键基因，其中蔗糖合酶基因PGSC0003DMG400013547在大西洋整个生育期表达量较高，且在各时期表达量均高于定薯1号；果糖激酶基因PGSC0003DMG400026916在a、b时期大西洋的表达量显著高于定薯1号；定薯1号中淀粉酶基因PGSC0003DMG400009891、PGSC0003DMG400001549和葡聚糖内切-1,3-β-葡萄糖苷酶基因PGSC0003DMG400024642、PGSC0003DMG400003181分别在c和e时期表达量显著高于高淀粉品种大西洋。上述基因可能是参与淀粉的合成与积累的关键调控基因。本研究为不同类型马铃薯品种块茎淀粉代谢调控机制研究提供参考。

Starch is one of the most important quality characteristics of potatoes, which is widely used in the food, medical, petrochemical and other industries. The demand for starchy potato varieties in the market is increasing year by year. To explore the characteristics and key genes of starch accumulation and regulation of potato tuber, in this study, transcriptome profiling of creeping stems (a), pre-tuber expansion (b), mid-tuber expansion (c), late tuber expansion (d), and mature stage (e) of high and low starch potato cultivars DXY and DS1 by RNA sequencing analysis, and a total of 9494 differentially expressed genes (DEGs) were identified at five stages. Binding function annotation revealed that the differential genes were mainly enriched in molecular functions such as binding and catalytic activity. Metabolic pathway analysis revealed that the differential genes were mainly enriched in carbohydrate-related metabolic pathways, of which 137 DEGs were associated with starch and sucrose metabolism. Nine key genes regulating starch synthesis were examined, and the relative expression level of the sucrose synthase gene PGSC0003DMG400013547 was higher during growth period of DXY than that at any stage. The relative expression level of the fructokinase gene PGSC0003DMG400026916 was significantly higher in DXY than in DS1 during the a and b periods. The relative expression level of amylase gene PGSC0003DMG400009891, PGSC0003DMG400001549, and glucan endo-1,3-β-glucosidase gene PGSC0003DMG400024642, PGSC0003DMG400003181 in DS1 was significantly higher than that in DXY with starch-rich cultivars during the c and e periods. The described gene might be a key regulatory gene for starch synthesis and accumulation. This study provides a clue for the investigation of the regulatory mechanism of tuber starch metabolism in different potato cultivars.