Rice plant architecture is an important agronomic trait and a major determinant in high productivity. Panicle erectness is the preferred plant architecture in japonica rice, but the molecular mechanism underlying domestication of the erect panicle remains elusive. Here we report the map-based cloning of a major quantitative trait locus, qPE9-1, which plays an integral role in regulation of rice plant architecture including panicle erectness. The R6547 qPE9-1 gene encodes a 426-amino-acid protein, homologous to the keratin-associated protein 5-4 family. The gene is composed of three Von Willebrand factor type C domains, one transmembrane domain, and one 4-disulfide-core domain. Phenotypic comparisons of a set of near-isogenic lines and transgenic lines reveal that the functional allele (qPE9-1) results in drooping panicles, and the loss-of-function mutation (qpe9-1) leads to more erect panicles. In addition, the qPE9-1 locus regulates panicle and grain length, grain weight, and consequently grain yield. We propose that the panicle erectness trait resulted from a natural random loss-of-function mutation for the qPE9-1 gene and has subsequently been the target of artificial selection during japonica rice breeding.
水稻株型是一個重要的農(nóng)藝性狀，對高產(chǎn)具有主要的決定作用。直立穗在粳稻育種中被廣泛應(yīng)用，然而直立穗馴化的分子機(jī)制依然未知。本研究，我們圖位克隆了一個主效數(shù)量性狀基因qPE9-1，其對水稻形態(tài)建成具有整體作用，包括對直立穗性狀。來源于水稻品種R6547的qPE9-1基因，編碼一個含有426個氨基酸的蛋白，是角蛋白5-4家族的成員。這個基因包括3個血管性血友病因子(vWF)C型結(jié)構(gòu)域，1個跨膜結(jié)構(gòu)域，1個4-硫化物-核心結(jié)構(gòu)域。對一系列近等基因系和轉(zhuǎn)基因系進(jìn)行表型比較，結(jié)果顯示功能等位基因(qPE9-1)導(dǎo)致彎曲穗，功能缺失突變等位基因(qpe9-1)導(dǎo)致直立穗。此外，qPE9-1基因還控制穗長、粒長、粒重，進(jìn)而控制產(chǎn)量。我們推測直立穗性狀來源于qPE9-1基因一個自然的隨機(jī)的功能缺失突變，隨后在粳稻育種中通過人工選擇被固定下來。