National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China.
Key Laboratory of State Ethnic Affairs Commission for Biological Technology, College of Life Sciences, South-Central University for Nationalities, Wuhan, China.
J Exp Bot. 2018 Aug 14;69(18):4283-4293. doi: 10.1093/jxb/ery232.
Heading date and panicle architecture are important agronomic traits in rice. Here, we identified a gene MOTHER OF FT AND TFL1 (OsMFT1) that regulates rice heading and panicle architecture. Overexpressing OsMFT1 delayed heading date by over 7 d and greatly increased spikelets per panicle and the number of branches. In contrast, OsMFT1 knockout mutants had an advanced heading date and reduced spikelets per panicle. Overexpression of OsMFT1 significantly suppressed Ehd1 expression, and Ghd7 up-regulated OsMFT1 expression. Double mutants showed that OsMFT1 acted downstream of Ghd7. In addition, transcription factor OsLFL1 was verified to directly bind to the promoter of OsMFT1 via an RY motif and activate the expression of OsMFT1 in vivo and in vitro. RNA-seq and RNA in situ hybridization analysis confirmed that OsMFT1 repressed expression of FZP and five SEPALLATA-like genes, indicating that the transition from branch meristem to spikelet meristem was delayed and thus more panicle branches were produced. Therefore, OsMFT1 is a suppressor of flowering acting downstream of Ghd7 and upstream of Ehd1, and a positive regulator of panicle architecture.
标题日期和穗型结构是水稻的重要农艺性状。在这里，我们鉴定了一个基因 MOTHER OF FT 和 TFL1（OsMFT1），它调节水稻的抽穗期和穗型结构。过表达 OsMFT1 使抽穗期延迟了 7 天以上，并大大增加了每穗小穗数和分支数。相比之下，OsMFT1 敲除突变体的抽穗期提前，每穗小穗数减少。过表达 OsMFT1 显著抑制了 Ehd1 的表达，而 Ghd7 上调了 OsMFT1 的表达。双突变体表明 OsMFT1 作用于 Ghd7 的下游。此外，转录因子 OsLFL1 通过 RY 基序被验证可以直接结合到 OsMFT1 的启动子上，并在体内和体外激活 OsMFT1 的表达。RNA-seq 和 RNA 原位杂交分析证实，OsMFT1 抑制了 FZP 和五个 SEPALLATA 样基因的表达，表明从侧芽分生组织到小穗分生组织的转变被延迟，从而产生了更多的穗分支。因此，OsMFT1 是一个下游作用于 Ghd7、上游作用于 Ehd1 的开花抑制因子，也是穗型结构的正调控因子。
