Basic Forestry & Proteomics Center (BFPC), College of Forestry, Fujian Agriculture and Forestry University, 350002 Fuzhou, China.
Institute of Science and Technology Austria, Klosterneuburg, 3400, Austria.
Development. 2019 Sep 12;146(17):dev175919. doi: 10.1242/dev.175919.
The apical hook is a transiently formed structure that plays a protective role when the germinating seedling penetrates through the soil towards the surface. Crucial for proper bending is the local auxin maxima, which defines the concave (inner) side of the hook curvature. As no sign of asymmetric auxin distribution has been reported in embryonic hypocotyls prior to hook formation, the question of how auxin asymmetry is established in the early phases of seedling germination remains largely unanswered. Here, we analyzed the auxin distribution and expression of PIN auxin efflux carriers from early phases of germination, and show that bending of the root in response to gravity is the crucial initial cue that governs the hypocotyl bending required for apical hook formation. Importantly, polar auxin transport machinery is established gradually after germination starts as a result of tight root-hypocotyl interaction and a proper balance between abscisic acid and gibberellins.This article has an associated 'The people behind the papers' interview.
顶端弯钩是一种暂时形成的结构，当萌发的幼苗穿透土壤朝向表面时，它起到保护作用。适当弯曲的关键是局部生长素最大值，它定义了弯钩曲率的凹（内）侧。由于在弯钩形成之前，尚未报道胚胎下胚轴中存在不对称生长素分布的迹象，因此，在幼苗萌发的早期阶段，生长素不对称性是如何建立的问题在很大程度上仍未得到解答。在这里，我们分析了早期萌发过程中的生长素分布和 PIN 生长素外排载体的表达，并表明根对重力的弯曲是控制形成顶端弯钩所需的下胚轴弯曲的关键初始线索。重要的是，极性生长素运输机制在萌发开始后逐渐建立，这是由于紧密的根-下胚轴相互作用以及脱落酸和赤霉素之间的适当平衡。本文有一个相关的“论文背后的人物”采访。
