Wang Zhongni, Chen Doudou, Lin Xuelei, Wang Jing, Arif Muhammad, Li Jiali, Gong Yanlong, Lei Yue, Wu Xian, Wu Chaoxin, Zhu Susong, Li Luhua
Guizhou Rice Research Institute, Guizhou Academy of Agricultural Science, Guiyang, 550006, China.
Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China.
Rice (N Y). 2025 Aug 13;18(1):76. doi: 10.1186/s12284-025-00833-0.
Precise regulation of floral primordia initiation is essential for normal flower development. However, the mechanisms regulating floral primordia initiation (PI) are complex and poorly understood. Herein, we identified a natural mutant in rice, stamen less (sl), which develops florets with reduced stamen number and no carpel due to defects in stamen and carpel PI. STAMENLESS (SL) encodes the CC-type glutaredoxin OsROXY2 and is involved in the regulation of stamen PI. OsROXY1, the closest homolog of OsROXY2, showed no function in stamen PI regulation. The osroxy1 single mutant showed normal reproductive development, while the floret phenotypes of osroxy1/2 double mutant were comparable to those of osroxy2 mutant. The TGA transcription factor OsbZIP47 showed a strong interaction with OsROXY2, and the two genes exhibited overlapping subcellular localizations and expression patterns during flower development. The number of stamens in the osbzip47 mutant was increased to seven (around 35%), indicating that OsbZIP47 is a negative regulator of stamen PI, in contrast to OsROXY2. Taken together, our results reveal that OsROXY2 regulates stamen number via interaction with OsbZIP47, indicating GRX-TGA-mediated floral organ number regulation mechanism is conserved in monocots and eudicots.
精确调控花原基起始对于正常的花发育至关重要。然而，调控花原基起始（PI）的机制复杂且鲜为人知。在此，我们在水稻中鉴定出一个自然突变体，即少雄蕊（sl），由于雄蕊和心皮PI存在缺陷，其发育出的小花雄蕊数量减少且无心皮。无雄蕊（SL）编码CC型谷氧还蛋白OsROXY2，并参与雄蕊PI的调控。OsROXY2的最接近同源物OsROXY1在雄蕊PI调控中无功能。osroxy1单突变体表现出正常的生殖发育，而osroxy1/2双突变体的小花表型与osroxy2突变体相当。TGA转录因子OsbZIP47与OsROXY2表现出强烈相互作用，并且这两个基因在花发育过程中呈现重叠的亚细胞定位和表达模式。osbzip47突变体的雄蕊数量增加到7个（约35%），表明与OsROXY2相反，OsbZIP47是雄蕊PI的负调控因子。综上所述，我们的结果揭示OsROXY2通过与OsbZIP47相互作用来调控雄蕊数量，表明GRX-TGA介导的花器官数量调控机制在单子叶植物和双子叶植物中是保守的。
