Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Fujian Agriculture & Forestry University, Fuzhou 350002, China.
Plant J. 2012 Dec;72(5):829-42. doi: 10.1111/j.1365-313X.2012.05126.x. Epub 2012 Oct 15.
Recent studies have shown that F-box proteins constitute a large family in eukaryotes, and play pivotal roles in regulating various developmental processes in plants. However, their functions in monocots are still obscure. In this study, we characterized a recessive mutant dwarf and deformed flower 1-1 (ddf1-1) in Oryza sativa (rice). The mutant is abnormal in both vegetative and reproductive development, with significant size reduction in all organs except the spikelet. DDF1 controls organ size by regulating both cell division and cell expansion. In the ddf1-1 spikelet, the specification of floral organs in whorls 2 and 3 is altered, with most lodicules and stamens being transformed into glume-like organs and pistil-like organs, respectively, but the specification of lemma/palea and pistil in whorls 1 and 4 is not affected. DDF1 encodes an F-box protein anchored in the nucleolus, and is expressed in almost all vegetative and reproductive tissues. Consistent with the mutant floral phenotype, DDF1 positively regulates B-class genes OsMADS4 and OsMADS16, and negatively regulates pistil specification gene DL. In addition, DDF1 also negatively regulates the Arabidopsis LFY ortholog APO2, implying a functional connection between DDF1 and APO2. Collectively, these results revealed that DDF1, as a newly identified F-box gene, is a crucial genetic factor with pleiotropic functions for both vegetative growth and floral organ specification in rice. These findings provide additional insights into the molecular mechanism controlling monocot vegetative and reproductive development.
最近的研究表明，F-box 蛋白在真核生物中构成一个大家族，在植物的各种发育过程中发挥关键作用。然而，它们在单子叶植物中的功能仍然不清楚。在这项研究中，我们对水稻中的隐性突变体矮化和畸形花 1-1（ddf1-1）进行了表征。该突变体在营养和生殖发育方面均出现异常，除了小穗外，所有器官均显著缩小。DDF1 通过调节细胞分裂和细胞扩张来控制器官大小。在 ddf1-1 的小穗中，第 2 和第 3 轮花器官的特化发生改变，大多数浆片和雄蕊分别转化为颖片状器官和雌蕊状器官，但第 1 和第 4 轮的外稃/内稃和雌蕊的特化不受影响。DDF1 编码一种锚定在核仁中的 F-box 蛋白，在几乎所有营养和生殖组织中都有表达。与突变体的花表型一致，DDF1 正向调控 B 类基因 OsMADS4 和 OsMADS16，负向调控雌蕊特化基因 DL。此外，DDF1 还负向调控拟南芥 LFY 同源物 APO2，表明 DDF1 和 APO2 之间存在功能联系。综上所述，这些结果表明，DDF1 作为一个新鉴定的 F-box 基因，是一个在水稻营养生长和花器官特化方面具有多效性功能的关键遗传因子。这些发现为控制单子叶植物营养和生殖发育的分子机制提供了更多的见解。
