Stomatal Patterning and Differentiation by Synergistic Interactions of Leucine-rich Repeat Receptor Kinases

陆地植物的成功适应依赖于防止水分流失的机制，同时允许植物和大气之间有效的气体交换。气体交换是通过气孔复合体进行的，气孔复合体由一对保护细胞组成，它们的作用就像一个膨胀驱动的阀门。从拟南芥中分离到的气孔密度升高和气孔聚集的突变体表明，气孔模式受遗传调控。本项目主要研究细胞-细胞信号机制调控气孔模式和分化。三种erecta家族受体样激酶（RLKs）的完全缺失导致高密度气孔簇的产生。进一步分析不同的勃起科突变体组合表明，这三种RLKs在气孔分化的两个关键步骤中具有重叠但不同的功能：(1)原始真皮细胞进入增生分裂或不对称分裂以产生气孔复合体的初始决定；(2)决定维持气孔干细胞活性，阻止保卫细胞的终末分化。与已知气孔模式突变体too many mouth （tmm）的遗传相互作用揭示了化学计量优势和组合特异性新形态。这些发现表明，TMM受体样蛋白对erecta家族RLKs的负调控对气孔正常分化至关重要。具体目的是：1)确定三种erecta家族受体激酶在表皮分化过程中的作用。2)研究三种受体激酶与已知气孔分化参与者的相互作用。3)利用敏化突变体背景，寻找气孔模式和分化的新调控因子。拟议的研究可能会导致重要的农业应用，因为控制气孔分布和模式的能力可能会影响光合效率，从而影响作物植物的生物量生产。博士后，研究生和本科生，其中许多是女性和不同种族背景，将有很好的机会获得植物生物学和分子遗传学方面的广泛培训。

The successful adaptation of land plants relied on mechanisms that prevent water loss while allowing efficient gas exchange between plants and the atmosphere. Gas exchange takes place through a stomatal complex, which consists of a pair of guard cells that operate as a turgor-driven valve. Isolation of Arabidopsis mutants with elevated stomatal density and stomatal clustering reveals that stomatal patterning is under genetic regulation. This research project focuses on the cell-cell signaling mechanism regulating stomatal patterning and differentiation. A complete loss of three ERECTA-family receptor-like kinases (RLKs) leads to the generation of high-density stomatal clusters. Further analysis of different erecta-family mutant combinations shows that the three RLKs possess overlapping but distinct functions in two critical steps of stomatal differentiation: (1) the initial decision of protodermal cells to enter proliferative division or asymmetric division to generate stomatal complexes; and (2) the decision to maintain stomatal stem cell activity and prevent terminal differentiation of guard cells. Genetic interactions with a known stomatal patterning mutant, too many mouth (tmm), reveals stoichiometric epistasis and combination-specific neomorphism. These findings suggest that negative regulation of ERECTA-family RLKs by TMM receptor-like protein, is critical for proper stomatal differentiation. The specific aims are:1) to determine the roles of three ERECTA-family receptor kinases during epidermal differentiation.2) to investigate interactions of three receptor kinases with known players of stomatal differentiation.3) to identify novel regulators of stomatal patterning and differentiation by taking advantage of a sensitized mutant background.The proposed research may lead to important agricultural applications, since the ability to manipulate stomatal distribution and patterning may influence photosynthetic efficiency and hence the biomass production of crop plants. A postdoctoral associate, a graduate student and undergraduates, many of whom are women and of diverse ethnic backgrounds, will have excellent opportunities to obtain broad training in plant biology and molecular genetics.