State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, 210095, China.
State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, 210095, China.
Plant Sci. 2019 Nov;288:110239. doi: 10.1016/j.plantsci.2019.110239. Epub 2019 Aug 29.
Specification of floral organ identity is critical for floral morphology and inflorescence architecture. Floral organ identity in plants is controlled by floral homeotic A/B/C/D/E-class genes. Although multiple genes regulate floral organogenesis, our understanding of the regulatory network remains fragmentary. Here, we characterized a rice floral organ gene KAIKOUXIAO (KKX), mutation of which produces an uncharacteristic open hull, abnormal seed and semi-sterility. KKX encodes a putative LEUNIG-like (LUGL) transcriptional regulator OsLUGL. OsLUGL is preferentially expressed in young panicles and its protein can interact with OsSEU, which functions were reported as an adaptor for LEUNIG. OsLUGL-OsSEU functions together as a transcriptional co-regulatory complex to control organ identity. SEP3 (such as OsMADS8) and AP1 (such as OsMADS18) serve as the DNA-binding partner of OsLUGL-OsSEU complex. Further studies indicated that OsMADS8 and OsMADS18 could bind to the promoter of OsGH3-8. The altered expression of OsGH3-8 might cause the increased auxin level and the decreased expression of OsARFs. Overall, our results demonstrate a possible pathway whereby OsLUGL-OsSEU-OsAP1-OsSEP3 complex as a transcriptional co-regulator by targeting the promoter of OsGH3-8, then affecting auxin level, OsARFs expression and thereby influencing floral development. These findings provide a valuable insight into the molecular functions of OsLUGL in rice floral development.
花器官特征的确定对于花的形态和花序结构至关重要。植物的花器官特征由花同源异型 A/B/C/D/E 类基因控制。尽管多个基因调控花器官发生，但我们对调控网络的理解仍然是零散的。在这里，我们描述了一个水稻花器官基因 KAIKOUXIAO（KKX），其突变产生了一种特征性的开放颖壳、异常种子和半不育。KKX 编码一个假定的 LEUNIG 样（LUGL）转录调节因子 OsLUGL。OsLUGL 在幼穗中优先表达，其蛋白可以与 OsSEU 相互作用，OsSEU 的功能被报道为 LEUNIG 的衔接子。OsLUGL-OsSEU 作为一个转录共调节复合物共同作用，以控制器官特征。SEP3（如 OsMADS8）和 AP1（如 OsMADS18）作为 OsLUGL-OsSEU 复合物的 DNA 结合伴侣。进一步的研究表明，OsMADS8 和 OsMADS18 可以结合到 OsGH3-8 的启动子上。OsGH3-8 的表达改变可能导致生长素水平升高和 OsARFs 表达降低。总的来说，我们的结果表明，OsLUGL-OsSEU-OsAP1-OsSEP3 复合物可能作为一个转录共调节因子，通过靶向 OsGH3-8 的启动子，然后影响生长素水平、OsARFs 的表达，从而影响花的发育。这些发现为 OsLUGL 在水稻花发育中的分子功能提供了有价值的见解。
