The modification of plant architecture is a crucial target in rice domestication and modern genetic improvement. Although several genes regulating rice plant architecture have been characterized, the molecular mechanisms underlying rice plant architecture domestication remain largely unclear. Here we show that the inclined tiller growth in wild rice is controlled by a single dominant gene, TILLER INCLINED GROWTH 1 (TIG1), which is located on chromosome 8 and encodes a TCP transcriptional activator. TIG1 is primarily expressed in the adaxial side of the tiller base, promotes cell elongation, and enlarges the tiller angle in wild rice. Variations in the TIG1 promoter of indica cultivars (tig1 allele) resulted in decreased expression of TIG1 in the adaxial side of tiller base and reduced cell length and tiller angle, leading to the transition from inclined tiller growth in wild rice to erect tiller growth during rice domestication. TIG1 positively regulates the expression of EXPA3, EXPB5, and SAUR39 to promote cell elongation and increase the tiller angle. Selective sweep analysis revealed that the tig1 allele was selected in indica cultivars by human beings. The cloning and characterization of TIG1 supports a new scenario of plant architecture evolution in rice.

植物结构的改变是水稻驯化和现代遗传改良的关键目标。尽管已经描述了几种调节水稻植株结构的基因，但基本上尚不清楚水稻植株结构驯化的分子机制。在这里，我们显示野生稻中的倾斜分till生长受单个显性基因TILLER INCLINED GROWTH 1（TIG1）的控制，该基因位于8号染色体上并编码TCP转录激活因子。TIG1 主要在分er基部的近端表达，促进细胞伸长，并扩大野生稻的分er角。在变化TIG1的启动子籼稻栽培种（TIG1等位基因）导致分IG基部近端TIG1表达降低，细胞长度和分till角度减小，导致稻米驯化过程中野生稻从倾斜分till生长向直立分till生长过渡。TIG1积极调节EXPA3，EXPB5和SAUR39的表达，从而促进细胞伸长并增加分er角度。选择性扫分析表明，TIG1等位基因在选定的籼稻品种的人类。TIG1的克隆和表征支持水稻植物结构进化的新场景。