Centre for Plant Sciences, University of Leeds, Leeds, UK.
Laboratory of Biochemistry, Wageningen University, Wageningen, The Netherlands.
Sci Rep. 2017 Mar 3;7:42664. doi: 10.1038/srep42664.
Root and shoot branches are major determinants of plant form and critical for the effective capture of resources below and above ground. These branches are often maintained at specific angles with respect to gravity, known as gravitropic set point angles (GSAs). We have previously shown that the mechanism permitting the maintenance of non-vertical GSAs is highly auxin-dependent and here we investigate the developmental and environmental regulation of root and shoot branch GSA. We show that nitrogen and phosphorous deficiency have opposing, auxin signalling-dependent effects on lateral root GSA in Arabidopsis: while low nitrate induces less vertical lateral root GSA, phosphate deficiency results in a more vertical lateral root growth angle, a finding that contrasts with the previously reported growth angle response of bean adventitious roots. We find that this root-class-specific discrepancy in GSA response to low phosphorus is mirrored by similar differences in growth angle response to auxin treatment between these root types. Finally we show that both shaded, low red/far-red light conditions and high temperature induce more vertical growth in Arabidopsis shoot branches. We discuss the significance of these findings in the context of efforts to improve crop performance via the manipulation of root and shoot branch growth angle.
根和茎的分枝是植物形态的主要决定因素，对地上和地下资源的有效获取至关重要。这些分枝通常以相对于重力的特定角度维持，称为向重力性设定点角度（GSAs）。我们之前已经表明，允许维持非垂直 GSA 的机制高度依赖于生长素，在这里我们研究根和茎分枝 GSA 的发育和环境调节。我们表明，氮和磷缺乏对拟南芥侧根 GSA 有相反的、生长素信号依赖性的影响：虽然低硝酸盐诱导的侧根 GSA 不那么垂直，但缺磷会导致侧根生长角度更垂直，这一发现与之前报道的豆科不定根的生长角度反应形成对比。我们发现，这种对低磷 GSA 反应的根类特异性差异，反映在这些根类型对生长素处理的生长角度反应中存在类似的差异。最后，我们表明，遮荫、低红/远红光条件和高温都会诱导拟南芥茎分枝更垂直的生长。我们讨论了这些发现在通过操纵根和茎分枝生长角度来提高作物性能的努力中的意义。
