Joint International Research Laboratory of Metabolic & Developmental Sciences, State Key Laboratory of Hybrid Rice, Shanghai Jiao Tong University-University of Adelaide Joint Centre for Agriculture and Health, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China.
Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Científicas-Universidad Politécnica de Valencia, Valencia, Spain.
J Exp Bot. 2017 Jan 1;68(3):483-498. doi: 10.1093/jxb/erw459.
The floral meristem (FM) is self-maintaining at the early stages of flower development, but it is terminated when a fixed number of floral organs are produced. The FLORAL ORGAN NUMBER4 (FON4; also known as FON2) gene, an ortholog of Arabidopsis CLAVATA3 (CLV3), is required for regulating FM size and determinacy in rice. However, its interactions with floral homeotic genes remain unknown. Here, we report the genetic interactions between FON4 and floral homeotic genes OsMADS15 (an A-class gene), OsMADS16 (also called SUPERWOMAN1, SPW1, a B-class gene), OsMADS3 and OsMADS58 (C-class genes), OsMADS13 (a D-class gene), and OsMADS1 (an E-class gene) during flower development. We observed an additive phenotype in the fon4 double mutant with the OsMADS15 mutant allele dep (degenerative palea). The effect on the organ number of whorl 2 was enhanced in fon4 spw1. Double mutant combinations of fon4 with osmads3, osmads58, osmads13, and osmads1 displayed enhanced defects in FM determinacy and identity, respectively, indicating that FON4 and these genes synergistically control FM activity. In addition, the expression patterns of all the genes besides OsMADS13 had no obvious change in the fon4 mutant. This work reveals how the meristem maintenance gene FON4 genetically interacts with C, D, and E floral homeotic genes in specifying FM activity in monocot rice.
花分生组织（FM）在花发育的早期阶段自我维持，但当产生固定数量的花器官时，它就会终止。FLORAL ORGAN NUMBER4（FON4；也称为 FON2）基因是拟南芥 CLAVATA3（CLV3）的同源物，对于调节水稻 FM 的大小和确定性是必需的。然而，它与花同源基因的相互作用仍然未知。在这里，我们报告了 FON4 与花同源基因 OsMADS15（A 类基因）、OsMADS16（也称为 SUPERWOMAN1、SPW1、B 类基因）、OsMADS3 和 OsMADS58（C 类基因）、OsMADS13（D 类基因）和 OsMADS1（E 类基因）在花发育过程中的遗传相互作用。我们观察到 fon4 双突变体与 OsMADS15 突变等位基因 dep（退化颖片）的加性表型。在 fon4 spw1 中，对第 2 轮器官数的影响增强。fon4 与 osmads3、osmads58、osmads13 和 osmads1 的双突变组合分别显示出 FM 确定性和身份的增强缺陷，表明 FON4 和这些基因协同控制 FM 活性。此外，除了 OsMADS13 之外，所有基因的表达模式在 fon4 突变体中没有明显变化。这项工作揭示了维持分生组织的基因 FON4 如何与单子叶水稻中 C、D 和 E 花同源基因在指定 FM 活性方面发生遗传相互作用。
