Yu Qi, Chen Liang, Zhou Wenqi, An Yanhuang, Luo Tengxiao, Wu Zhongliang, Wang Yuqi, Xi Yunfeng, Yan Longfeng, Hou Suiwen
Key Laboratory of Cell Activities and Stress Adaptations, Ministry of Education, School of Life Sciences, Lanzhou University, Lanzhou, China.
Front Plant Sci. 2020 Nov 30;11:600021. doi: 10.3389/fpls.2020.600021. eCollection 2020.
Stomatal density is an important factor that determines the efficiency of plant gas exchange and water transpiration. Through forward genetics, we screened a mutant () with decreased stomatal density and clustered stomata in rice (). After the first asymmetric division, some of the larger sister cells undergo an extra asymmetric division to produce a small cell neighboring guard mother cell. Some of these small cells develop into stomata, which leads to stomatal clustering, and the rest arrested or developed into pavement cell. After map-based cloning, we found the protein encoded by this gene containing DUF630 and DUF632 domains. Evolutionary analysis showed that the gene family differentiated earlier in land plants. It was found that the deletion of would lead to the disorder of gene expression regarding stomatal development, especially the expression of (). Through the construction of deletion mutants by CRISPR-Cas9, we found that, similar to mutants, the mutants have clustered stomata and extra small cells adjacent to the stomata. and are both required for inhibiting ectopic asymmetric cell divisions (ACDs) and clustered stomata. By dehydration stress assay, the decreased stomatal density of mutants enhanced their dehydration avoidance. This study characterized the functions of and in rice stomatal development. Our findings will be helpful in developing drought-resistant crops through controlling the stomatal density.
气孔密度是决定植物气体交换和水分蒸腾效率的重要因素。通过正向遗传学，我们筛选到了一个水稻气孔密度降低且气孔成簇的突变体（）。在第一次不对称分裂后，一些较大的姐妹细胞会进行额外的不对称分裂，产生一个与保卫母细胞相邻的小细胞。其中一些小细胞发育成气孔，导致气孔成簇，其余的则停滞或发育成表皮细胞。通过图位克隆，我们发现该基因编码的蛋白质含有DUF630和DUF632结构域。进化分析表明，该基因家族在陆地植物中分化较早。研究发现，的缺失会导致气孔发育相关基因表达紊乱，尤其是（）的表达。通过CRISPR-Cas9构建缺失突变体，我们发现，与突变体类似，突变体也有气孔成簇现象，且在气孔附近有额外的小细胞。和对于抑制异位不对称细胞分裂（ACD）和成簇气孔都是必需的。通过脱水胁迫试验，突变体降低的气孔密度增强了它们的脱水避免能力。本研究对和在水稻气孔发育中的功能进行了表征。我们的研究结果将有助于通过控制气孔密度来培育抗旱作物。
