水稻灌浆和淀粉积累关键基因获揭示

记者日前从中国科学院植物研究所获悉，该所刘春明研究组通过一系列实验，发现了直接调控水稻灌浆和淀粉积累的关键基因。相关研究成果在线发表于《细胞研究》。

刘春明研究组利用芯片杂交、荧光定量聚合酶链式反应和原位杂交等实验，发现了一个在水稻籽粒背侧糊粉层特异表达的转录因子。研究人员对该基因进行敲除和表达干扰发现，该基因直接调控水稻的灌浆和淀粉累积，并且敲除该基因的突变体籽粒中的蔗糖、葡萄糖和果糖含量均大幅度下降。进一步生化分析发现，该基因通过直接结合于三个蔗糖转运蛋白的基因表达调控区来调控蔗糖直接进入胚乳。

该研究成果对于理解禾本科作物的灌浆机理具有重要意义，有可能为提高作物产量提供新工具。

据了解，水稻胚乳是人类最主要的粮食来源之一，其结构包含内侧的淀粉胚乳和外侧的糊粉层。叶片光合作用产生的碳水化合物主要以蔗糖形式从筛管组织运输到籽粒。前人的研究认为蔗糖在到达籽粒之后先分解成果糖和葡萄糖，然后通过单糖转运蛋白运输至淀粉胚乳进而合成淀粉。蔗糖是否直接进入、如何进入淀粉胚乳的机制一直不很清楚。（来源：中国科学报 丁佳）

NF-YB1-regulated expression of sucrose transporters in aleurone facilitates sugar loading to rice endosperm

Abstract In this study, microarray analyses were performed in rice (Oryza sativa L., Zhonghua 11) to identify transcription factors (TFs) differentially expressed between starchy endosperm and aleurone in caryopses collected at 11 to 14 days after pollination (DAP), a stage when grain filling is active. Out of 949 TFs that were differentially expressed, 505 were up-regulated in the aleurone. Real-time PCR was performed to examine their expression patterns further. Os02g0725900 encoding Nuclear Factor Y B1 (NF-YB1) was shown to be expressed in caryopses from 4 to 21 DAP (c4 to c21), similar to the result published recently, while no expression was detected in vegetative tissues examined. Within caryopses, abundant NF-YB1 expression was detected in mixed aleurone-testa sample (a+t), but not in starchy endosperm.

原文链接：http://www.nature.com/cr/journal/vaop/ncurrent/pdf/cr2015116a.pdf