Rice Biotechnology Research Subteam (Hokuriku Region), National Agricultural Research Center, National Agriculture and Food Research Organization, Niigata 943-0193, Japan.
Plant Cell. 2009 Oct;21(10):3008-25. doi: 10.1105/tpc.109.068742. Epub 2009 Oct 9.
Floral organ identity and meristem determinacy in plants are controlled by combinations of activities mediated by MADS box genes. AGAMOUS-LIKE6 (AGL6)-like genes are MADS box genes expressed in floral tissues, but their biological functions are mostly unknown. Here, we describe an AGL6-like gene in rice (Oryza sativa), MOSAIC FLORAL ORGANS1 (MFO1/MADS6), that regulates floral organ identity and floral meristem determinacy. In the flower of mfo1 mutants, the identities of palea and lodicule are disturbed, and mosaic organs were observed. Furthermore, the determinacy of the floral meristem was lost, and extra carpels or spikelets developed in mfo1 florets. The expression patterns of floral MADS box genes were disturbed in the mutant florets. Suppression of another rice AGL6-like gene, MADS17, caused no morphological abnormalities in the wild-type background, but it enhanced the phenotype in the mfo1 background, indicating that MADS17 has a minor but redundant function with that of MFO1. Whereas single mutants in either MFO1 or the SEPALLATA-like gene LHS1 showed moderate phenotypes, the mfo1 lhs1 double mutant showed a severe phenotype, including the loss of spikelet meristem determinacy. We propose that rice AGL6-like genes help to control floral organ identity and the establishment and determinacy of the floral meristem redundantly with LHS1.
植物的花器官身份和分生组织决定由 MADS 盒基因介导的活性组合控制。AGAMOUS-LIKE6（AGL6）样基因是在花组织中表达的 MADS 盒基因，但它们的生物学功能大多未知。在这里，我们描述了水稻（Oryza sativa）中的一个 AGL6 样基因 MOSAIC FLORAL ORGANS1（MFO1/MADS6），它调节花器官身份和花分生组织决定。在 mfo1 突变体的花中，内稃和浆片的身份受到干扰，并且观察到镶嵌器官。此外，花分生组织的决定丧失，并且在 mfo1 小花中发育出额外的心皮或小穗。突变体小花中花 MADS 盒基因的表达模式受到干扰。另一个水稻 AGL6 样基因 MADS17 的抑制在野生型背景下没有引起形态异常，但在 mfo1 背景下增强了表型，表明 MADS17 具有次要但冗余的功能与 MFO1。而在单个 MFO1 或 SEPALLATA 样基因 LHS1 突变体中表现出中度表型，mfo1 lhs1 双突变体表现出严重表型，包括小穗分生组织决定丧失。我们提出，水稻 AGL6 样基因与 LHS1 冗余地帮助控制花器官身份以及花分生组织的建立和决定。
