Manuela Darren, Xu Mingli
Department of Biological Sciences, University of South Carolina, Columbia, SC, United States.
Front Plant Sci. 2020 Oct 30;11:568730. doi: 10.3389/fpls.2020.568730. eCollection 2020.
Leaves are the major organ for photosynthesis in most land plants, and leaf structure is optimized for the maximum capture of sunlight and gas exchange. Three polarity axes, the adaxial-abaxial axis, the proximal-distal axis, and the medial-lateral axis are established during leaf development to give rise to a flattened lamina with a large area for photosynthesis and blades that are extended on petioles for maximum sunlight. Adaxial cells are elongated, tightly packed cells with many chloroplasts, and their fate is specified by HD-ZIP III and related factors. Abaxial cells are rounder and loosely packed cells and their fate is established and maintained by YABBY family and KANADI family proteins. The activities of adaxial and abaxial regulators are coordinated by ASYMMETRIC LEAVES2 and auxin. Establishment of the proximodistal axis involves the BTB/POZ domain proteins BLADE-ON-PETIOLE1 and 2, whereas homeobox genes and mediate leaf development along the mediolateral axis. This review summarizes recent advances in leaf polarity establishment with a focus on the regulatory networks involved.
在大多数陆生植物中，叶片是进行光合作用的主要器官，其结构经过优化，以实现对阳光的最大捕获和气体交换。在叶片发育过程中会形成三个极性轴，即近轴-远轴轴、近端-远端轴和中侧轴，从而形成一个扁平的叶片，其具有大面积用于光合作用，并且叶片通过叶柄伸展以获取最大量的阳光。近轴细胞呈细长形，是紧密排列且含有许多叶绿体的细胞，其命运由HD-ZIP III及相关因子决定。远轴细胞更圆，是排列松散的细胞，其命运由YABBY家族和KANADI家族蛋白决定并维持。近轴和远轴调节因子的活性由ASYMMETRIC LEAVES2和生长素协调。近端-远端轴的建立涉及BTB/POZ结构域蛋白BLADE-ON-PETIOLE1和2，而同源异型盒基因 和 介导沿中侧轴的叶片发育。本综述总结了叶片极性建立方面的最新进展，重点关注其中涉及的调控网络。
