淀粉是植物和人类的重要能源,主要合成并储存在胚乳中,块茎,根茎,和子叶.鉴于直链淀粉在决定淀粉作物品质方面的重要作用,优化其含量已成为当前作物育种工作的关键目标。苦荞麦,双子叶植物,特别是在其胚乳中积累了高水平的直链淀粉,超过普通谷物如大米和玉米。然而,直链淀粉积累的潜在机制,分布,苦荞麦的调控仍不清楚。这里,在苦荞麦的各种组织和器官中测定了直链淀粉含量,确定胚乳是其生物合成和积累的主要部位。来自不同发育阶段的胚乳的RNA测序分析确定了可能参与淀粉生物合成的35个基因,有13个基因显示出高胚乳特异性表达,提示在淀粉生物合成中的关键作用。此外,转录因子FtNF-YB2在胚乳中特异性高表达,被发现可以增强直链淀粉的合成。此外,确定了具有潜在胚乳特异性活性的启动子,推进我们对直链淀粉调节的理解。此外,这项研究还表明,油菜素类固醇(BR)积极影响苦荞麦胚乳中直链淀粉的生物合成。这些发现为了解直链淀粉生物合成的机制提供了必要的见解,苦荞麦的积累与调控,对未来的育种策略具有重要意义。
Starch serves as a crucial energy source for both plants and humans, predominantly synthesized and stored in endosperms, tubers, rhizomes, and cotyledons. Given the significant role of amylose in determining the quality of starchy crops, optimizing its content has become a key objective in current crop breeding efforts. Tartary buckwheat, a dicotyledonous plant, notably accumulates high levels of amylose in its
endosperm, surpassing common cereals like rice and maize. However, the mechanisms underlying amylose accumulation, distribution, and regulation in Tartary buckwheat remain unclear. Here, amylose content was determined across various tissues and organs of Tartary buckwheat, identifying with the
endosperm as the primary site for its biosynthesis and accumulation. RNA sequencing analysis of endosperms from different developmental stages identified 35 genes potentially involved in starch biosynthesis, with 13 genes showing high endosperm-specific expression, suggesting crucial roles in starch biosynthesis. Additionally, the transcription factor FtNF-YB2, which was specifically highly expressed in the
endosperm, was discovered to enhance amylose synthesis. Moreover, promoters with potential
endosperm-specific activity were identified, advancing our understanding of amylose regulation. Additionally, this study also demonstrates that brassinosteroids (BR) positively influence amylose biosynthesis in Tartary buckwheat
endosperm. These findings provide essential insights into the mechanisms of understanding amylose biosynthesis, accumulation and regulation in Tartary buckwheat, offering significant implications for future breeding strategies.