• Organ size is determined mainly by cell division and cell expansion. Several genetic factors regulating development of plant lateral organs have been characterized, but those involved in determining reproductive organ size and separation in rice (Oryza sativa) remain unknown.
• We have isolated the rice gene SMALL REPRODUCTIVE ORGANS (SRO) encoding a nucleus-localized Cys2His2 (C₂H₂) zinc finger protein orthologous to Arabidopsis transcription factor (TF) SUPERMAN (SUP). Combined developmental, genetic, histological and transcriptomic analyses were used to determine the function of SRO in regulating reproductive organ size.
• SRO affects genes involved in cell division, cell expansion and phytohormone signalling in the rice flower. SRO is specifically expressed in the first stages of stamen filament development to regulate their correct formation and separation. In addition, SRO noncell-autonomously regulates the size and functionality of male and female reproductive organs. The B-class MADS-box gene OsMADS16/SPW1 is epistatic to SRO, whereas SRO regulates reproductive organ specification and floral meristem determinacy synergistically with C-class genes OsMADS3 and OsMADS58.
• These findings provide insights into how an evolutionarily conserved TF has a pivotal role in reproductive organ development in core eudicots and monocots, through partially conserved expression, function and regulatory network.

中文翻译：

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小生殖器官，一种类似超人的转录因子，调节水稻雄蕊和雌蕊的生长

• 器官大小主要由细胞分裂和细胞扩张决定。一些调节植物侧向器官发育的遗传因素已经被表征，但那些参与确定水稻（Oryza sativa）生殖器官大小和分离的因素仍然未知。
• 我们已经分离出水稻基因SMALL REPRODUCTIVE ORGANS ( SRO )，该基因编码与拟南芥转录因子 (TF) SUPERMAN (SUP) 直系同源的定位于细胞核的 Cys2His2 (C ₂ H ₂ ) 锌指蛋白。结合发育、遗传、组织学和转录组学分析来确定SRO在调节生殖器官大小中的功能。
• SRO影响水稻花中涉及细胞分裂、细胞扩增和植物激素信号传导的基因。SRO在雄蕊花丝发育的第一阶段特别表达，以调节它们的正确形成和分离。此外，SRO非细胞自主调节男性和女性生殖器官的大小和功能。B 类 MADS-box 基因OsMADS16 / SPW1对SRO上位，而SRO与 C 类基因OsMADS3和OsMADS58协同调节生殖器官规格和花分生组织决定性。
• 这些发现提供了关于进化上保守的 TF 如何通过部分保守的表达、功能和调控网络在核心真双子叶植物和单子叶植物的生殖器官发育中发挥关键作用的见解。