Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Fujian Agricultural & Forestry University, Fuzhou, China.
Plant Mol Biol. 2012 Nov;80(4-5):429-42. doi: 10.1007/s11103-012-9958-2. Epub 2012 Aug 30.
AGL6-clade genes are a subfamily of MADS-box genes and preferentially expressed in floral organs. OsMADS6 and OsMADS17 are two AGL6-like genes in rice. OsMADS17 has been shown to play a minor role in floral development and appears to result from a duplication of OsMADS6. OsMADS6 was initially named as MFO1 for mosaic floral organs based on its moderate mutant phenotypes. So far, four moderate or weak mutant alleles of OsMADS6 have been described, providing valuable insights into its role in flower development. Here, we report a null allele of OsMADS6 (Osmads6-5), which exhibited a strong mutant phenotype in spikelet without affecting vegetative traits, causing all floral organs except lemma homeotically transformed into lemma-like organs (LLOs) as well as an indeterminate floral meristem, thus resulting in a mutant floret consisting of reiterating whorls of lemma and LLOs. In consistently, over-expression of OsMADS6 led to additional lodicule-, stamen- and carpel-like organs. Expression analysis showed that OsMADS6 controls the formation of the incipient primordia of lodicule, stamen and carpel via regulating the expression of class B, C and SEP-like MADS-box genes. Taken together, our results revealed that OsMADS6 acts as a critical regulator for early flower development in rice and provide novel insights into the molecular mechanism of OsMADS6.
AGL6 基因簇是 MADS 框基因的一个亚家族，优先在花器官中表达。OsMADS6 和 OsMADS17 是水稻中的两个 AGL6 样基因。OsMADS17 在花发育中扮演次要角色，似乎是 OsMADS6 复制的结果。OsMADS6 最初因其中度突变表型而被命名为 MFO1（马赛克花器官）。到目前为止，已经描述了四个 OsMADS6 的中度或弱突变等位基因，为其在花发育中的作用提供了有价值的见解。在这里，我们报告了一个 OsMADS6 的 null 等位基因（Osmads6-5），它在小穗中表现出强烈的突变表型，而不影响营养性状，导致除了外稃同源转化为外稃样器官（LLO）之外的所有花器官，以及不定的花分生组织，从而导致一个由重复的外稃和 LLO 组成的突变小花。一致地，过表达 OsMADS6 导致额外的浆片、雄蕊和心皮样器官。表达分析表明，OsMADS6 通过调节 B、C 和 SEP 样 MADS 框基因的表达来控制浆片、雄蕊和心皮初生原基的形成。总之，我们的结果表明，OsMADS6 是水稻早期花发育的关键调控因子，并为 OsMADS6 的分子机制提供了新的见解。
