RETINOBLASTOMA-RELATED Genes Specifically Control Inner Floral Organ Morphogenesis and Pollen Development in Rice1
RETINOBLASTOMA-RELATED Genes Specifically Control Inner Floral Organ Morphogenesis and Pollen Development in Rice1
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视网膜母细胞瘤相关基因特异性控制水稻内部花器官形态发生和花粉发育
DOI：
10.1104/pp.19.00478
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发表时间：
2019-12-01
期刊：
影响因子：
7.4
通讯作者：
Wu, Weiren
中科院分区：
文献类型：
--
作者：
Duan, Yuanlin;Chen, Yaguang;Wu, Weiren
视网膜母细胞瘤相关基因（RETINOBLASTOMA-RELATED， RBR）是植物中必不可少的基因，但其在细胞周期进入过程中所起的作用之外的分子功能尚不清楚。利用正向遗传学和反向遗传学方法，研究了OsRBR1和OsRBR2在水稻生长发育中的功能。OsRBR1在花分生组织中高表达，调控花同源基因的表达，保证花器官的形成。OsRBR1突变导致花分生组织特性的丧失，导致小叶、雄蕊和雌蕊被穗状结构或外稃状器官的轮生结构所取代。OsRBR2在雄蕊中优先表达，促进花粉形成。OsRBR2突变导致花药变形，无花粉。与拟南芥花发育所必需的AtRBR和AtMSI1之间的蛋白相互作用类似，OsMSI1被鉴定为OsRBR1和OsRBR2的相互作用伙伴。OsMSI1在水稻（Oryza sativa）中普遍表达，似乎对发育至关重要，因为OsMSI1突变是致命的。这些结果表明，OsRBR1和OsRBR2与OsMSI1共同参与水稻生殖发育。这项工作进一步表征了rbr的功能，并提高了目前对水稻花形态和花粉形成的特定调控途径的理解。细胞周期相关基因家族成员维持水稻花分生组织功能，以确保花器官的形成和调节绒毡层降解，促进花粉形成。
RETINOBLASTOMA-RELATED (RBR) is an essential gene in plants, but its molecular function outside of its role in cell cycle entry remains poorly understood. We characterized the functions of OsRBR1 and OsRBR2 in plant growth and development in rice using both forward- and reverse-genetics methods. The two genes were coexpressed and performed redundant roles in vegetative organs but exhibited separate functions in flowers. OsRBR1 was highly expressed in the floral meristem and regulated the expression of floral homeotic genes to ensure floral organ formation. Mutation of OsRBR1 caused loss of floral meristem identity, resulting in the replacement of lodicules, stamens, and the pistil with either a panicle-like structure or whorls of lemma-like organs. OsRBR2 was preferentially expressed in stamens and promoted pollen formation. Mutation of OsRBR2 led to deformed anthers without pollen. Similar to the protein interaction between AtRBR and AtMSI1 that is essential for floral development in Arabidopsis, OsMSI1 was identified as an interaction partner of OsRBR1 and OsRBR2. OsMSI1 was ubiquitously expressed and appears to be essential for development in rice (Oryza sativa), as the mutation of OsMSI1 was lethal. These results suggest that OsRBR1 and OsRBR2 function with OsMSI1 in reproductive development in rice. This work characterizes further functions of RBRs and improves current understanding of specific regulatory pathways of floral specification and pollen formation in rice.Members of a cell-cycle-related gene family maintain floral meristem function to ensure floral organ origination and regulate tapetum degradation to promote pollen formation in rice.