Deslauriers Stephen D
Division of Science and Math, University of Minnesota, Morris, Morris, MN 56267, USA.
AoB Plants. 2021 Sep 24;13(5):plab063. doi: 10.1093/aobpla/plab063. eCollection 2021 Oct.
A primary component of seedling establishment is the photomorphogenic response as seedlings emerge from the soil. This process is characterized by a reduced growth rate in the hypocotyl, increased root growth, opening of the apical hook and expansion of the cotyledons as photosynthetic organs. While fundamental to plant success, the photomorphogenic response can be highly variable. Additionally, studies of are made difficult by subtle differences in growth rate between individuals. High-resolution imaging and computational processing have emerged as useful tools for quantification of such phenotypes. This study sought to: (i) develop an imaging methodology which could capture changes in growth rate as seedlings transition from darkness to blue light in real time, and (ii) apply this methodology to single-quantitative trait locus (QTL) analysis using the Cvi × L recombinant inbred line (RIL) mapping population. Significant differences in the photomorphogenic response were observed between the parent lines and analysis of 158 RILs revealed a wide range of growth rate phenotypes. Quantitative trait locus analysis detected significant loci associated with dark growth rate on chromosome 5 and significant loci associated with light growth rate on chromosome 2. Candidate genes associated with these loci, such as the previously characterized locus, highlight the application of this approach for QTL analysis. Genetic analysis of Landsberg lines without the mutation also supports a role for ER in modulating the photomorphogenic response, consistent with previous QTL analyses of this population. Strengths and limitations of this methodology are presented, as well as means of improvement.
幼苗建立的一个主要组成部分是幼苗从土壤中出土时的光形态建成反应。这个过程的特点是下胚轴生长速率降低、根系生长增加、顶端弯钩打开以及子叶作为光合器官展开。虽然光形态建成反应对植物的成功至关重要，但它可能具有高度变异性。此外，个体之间生长速率的细微差异使得对此的研究变得困难。高分辨率成像和计算处理已成为量化此类表型的有用工具。本研究旨在：（i）开发一种成像方法，能够实时捕捉幼苗从黑暗过渡到蓝光时生长速率的变化，以及（ii）将该方法应用于使用Cvi×L重组自交系（RIL）作图群体的单数量性状位点（QTL）分析。在亲本系之间观察到光形态建成反应的显著差异，对158个RIL的分析揭示了广泛的生长速率表型。数量性状位点分析检测到与第5号染色体上黑暗生长速率相关的显著位点以及与第2号染色体上光照生长速率相关的显著位点。与这些位点相关的候选基因，如先前已鉴定的 位点，突出了该方法在QTL分析中的应用。对没有 突变的Landsberg品系的遗传分析也支持ER在调节光形态建成反应中的作用，这与该群体先前的QTL分析一致。本文介绍了该方法的优点和局限性以及改进方法。
