Li Peijin, Wang Yonghong, Qian Qian, Fu Zhiming, Wang Mei, Zeng Dali, Li Baohua, Wang Xiujie, Li Jiayang
State Key Laboratory of Plant Genomics and National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.
Cell Res. 2007 May;17(5):402-10. doi: 10.1038/cr.2007.38.
Tiller angle of rice (Oryza sativa L.) is an important agronomic trait that contributes to grain production, and has long attracted attentions of breeders for achieving ideal plant architecture to improve grain yield. Although enormous efforts have been made over the past decades to study mutants with extremely spreading or compact tillers, the molecular mechanism underlying the control of tiller angle of cereal crops remains unknown. Here we report the cloning of the LAZY1 (LA1) gene that regulates shoot gravitropism by which the rice tiller angle is controlled. We show that LA1, a novel grass-specific gene, is temporally and spatially expressed, and plays a negative role in polar auxin transport (PAT). Loss-of-function of LA1 enhances PAT greatly and thus alters the endogenous IAA distribution in shoots, leading to the reduced gravitropism, and therefore the tiller-spreading phenotype of rice plants.
水稻（Oryza sativa L.）的分蘖角度是一个重要的农艺性状，对粮食生产有贡献，长期以来一直吸引着育种者的关注，以实现理想的株型结构来提高粮食产量。尽管在过去几十年里人们付出了巨大努力来研究具有极开张或紧凑分蘖的突变体，但谷类作物分蘖角度控制的分子机制仍然未知。在此，我们报告了LAZY1（LA1）基因的克隆，该基因通过调控地上部向重力性来控制水稻分蘖角度。我们表明，LA1是一个新的禾本科特有的基因，在时间和空间上表达，并在生长素极性运输（PAT）中起负作用。LA1功能缺失极大地增强了PAT，从而改变了地上部内源生长素的分布，导致向重力性降低，进而使水稻植株呈现分蘖开张的表型。
