Control of leaf vascular patterning by polar auxin transport
Control of leaf vascular patterning by polar auxin transport
复制标题
DOI：
10.1101/gad.1402406
复制
发表时间：
2006-04-15
影响因子：
10.5
通讯作者：
Berleth, T
中科院分区：
文献类型：
--
作者：
Scarpella, E;Marcos, D;Berleth, T
几个世纪以来，叶子维管束模式的形成一直让生物学家着迷。在早期的叶原基中，原形成层细胞的复杂网络从同质的表皮下组织中出现。潜在位置信息的分子性质尚不清楚，但各种证据表明植物激素生长素的运输路线在确定原形成层形成位点时逐渐受到限制。在这里，我们表明，生长素流出相关蛋白 AtPIN 家族的一个重要成员 AtPIN1 在前原形成层和原形成层细胞命运标记之前表达，其区域仅限于原形成层形成位点。亚细胞 AtPIN1 极性表明生长素被导向表皮中不同的“汇聚点”，从那里它定义了主要静脉的位置。所有新兴静脉中的综合极性表明生长素向先前存在的静脉排水，但静脉在两端连接时表现出不同的极性。生长素的应用和运输抑制揭示了汇聚点定位和 AtPIN1 表达域动力学是自组织、生长素运输依赖的过程。我们推导出所有静脉顺序的自我调节、重复图案化的模型，并假设其开始时有一个用于主静脉定位和叶序图案化的共同表皮生长素聚焦机制。
The formation of the leaf vascular pattern has fascinated biologists for centuries. In the early leaf primordium, complex networks of procambial cells emerge from homogeneous subepidermal tissue. The molecular nature of the underlying positional information is unknown, but various lines of evidence implicate gradually restricted transport routes of the plant hormone auxin in defining sites of procambium formation. Here we show that a crucial member of the AtPIN family of auxin-efflux-associated proteins, AtPIN1, is expressed prior to pre-procambial and procambial cell fate markers in domains that become restricted toward sites of procambium formation. Subcellular AtPIN1 polarity indicates that auxin is directed to distinct "convergence points" in the epidermis, from where it defines the positions of major veins. Integrated polarities in all emerging veins indicate auxin drainage toward pre-existing veins, but veins display divergent polarities as they become connected at both ends. Auxin application and transport inhibition reveal that convergence point positioning and AtPIN1 expression domain dynamics are self-organizing, auxin-transport-dependent processes. We derive a model for self-regulated, reiterative patterning of all vein orders and postulate at its onset a common epidermal auxin-focusing mechanism for major-vein positioning and phyllotactic patterning.