Yang W C, Ye D, Xu J, Sundaresan V
The Institute of Molecular Agrobiology, National University of Singapore, Singapore 117604.
Genes Dev. 1999 Aug 15;13(16):2108-17. doi: 10.1101/gad.13.16.2108.
The formation of haploid spores marks the initiation of the gametophytic phase of the life cycle of all vascular plants ranging from ferns to angiosperms. In angiosperms, this process is initiated by the differentiation of a subset of floral cells into sporocytes, which then undergo meiotic divisions to form microspores and megaspores. Currently, there is little information available regarding the genes and proteins that regulate this key step in plant reproduction. We report here the identification of a mutation, SPOROCYTELESS (SPL), which blocks sporocyte formation in Arabidopsis thaliana. Analysis of the SPL mutation suggests that development of the anther walls and the tapetum and microsporocyte formation are tightly coupled, and that nucellar development may be dependent on megasporocyte formation. Molecular cloning of the SPL gene showed that it encodes a novel nuclear protein related to MADS box transcription factors and that it is expressed during microsporogenesis and megasporogenesis. These data suggest that the SPL gene product is a transcriptional regulator of sporocyte development in Arabidopsis.
单倍体孢子的形成标志着从蕨类植物到被子植物等所有维管植物生命周期中配子体阶段的开始。在被子植物中，这一过程由一部分花细胞分化为孢子母细胞启动，这些孢子母细胞随后进行减数分裂形成小孢子和大孢子。目前，关于调控植物繁殖这一关键步骤的基因和蛋白质的信息很少。我们在此报告了对一种突变体SPOROCYTELESS（SPL）的鉴定，该突变体阻断了拟南芥中孢子母细胞的形成。对SPL突变的分析表明，花药壁、绒毡层的发育以及小孢子母细胞的形成紧密相关，并且珠心发育可能依赖于大孢子母细胞的形成。SPL基因的分子克隆表明，它编码一种与MADS盒转录因子相关的新型核蛋白，并且在小孢子发生和大孢子发生过程中表达。这些数据表明，SPL基因产物是拟南芥中孢子母细胞发育的转录调节因子。
