PDF(Pubmed)
Abstract：
The four-celled stomatal complex consists of a pair of guard cells (GCs) and two subsidiary cells (SCs) in grasses, which supports a fast adjustment of stomatal aperture. The formation and development of SCs are thus important for stomatal functionality. Here, we report a maize lost subsidiary cells (lsc) mutant, with many stomata lacking one or two SCs. The loss of SCs is supposed to have resulted from impeded subsidiary mother cell (SMC) polarization and asymmetrical division. Besides the defect in SCs, the lsc mutant also displays a dwarf morphology and pale and striped newly-grown leaves. LSC encodes a large subunit of ribonucleotide reductase (RNR), an enzyme involved in deoxyribonucleotides (dNTPs) synthesis. Consistently, the concentration of dNTPs and expression of genes involved in DNA replication, cell cycle progression, and SC development were significantly reduced in the lsc mutant compared with the wild-type B73 inbred line. Conversely, overexpression of maize LSC increased dNTP synthesis and promoted plant growth in both maize and Arabidopsis. Our data indicate that LSC regulates dNTP production and is required for SMC polarization, SC differentiation, and growth of maize.
摘要：
四细胞气孔复合体由一对保卫细胞（GC）和两个附属细胞（SC）组成，这有利于快速调整气孔孔径。因此,SC的形成和发育对于气孔功能是重要的。这里,我们报道了玉米缺失的辅助细胞（lsc）突变体，其中大量气孔缺乏一个或两个SC。SCs的丢失可能是由于辅助母细胞（SMC）极化和不对称分裂受阻所致。除了SCs的缺陷,lsc突变体还表现出矮小的形态和苍白和剥离的新生长的叶子。LSC编码核糖核苷酸还原酶（RNR）的大亚基，参与脱氧核糖核苷酸（dNTPs）合成的酶。始终如一，dNTPs水平和DNA复制相关基因的表达，细胞周期进程，与野生型B73自交系相比，lsc突变体的SC发育显着减少。相反，玉米LSC的过表达增加dNTP合成并促进玉米和拟南芥的植物生长。我们的数据表明，LSC调节dNTP的产生，是SMC极化所必需的，SC分化，和植物生长。
