Thompson Addie M, Yu Jianming, Timmermans Marja C P, Schnable Patrick, Crants James C, Scanlon Michael J, Muehlbauer Gary J
Department of Agronomy and Plant Genetics, University of Minnesota, St. Paul, Minnesota 55108.
Department of Agronomy, Iowa State University, Ames, Iowa 50011.
G3 (Bethesda). 2015 Mar 5;5(5):819-27. doi: 10.1534/g3.115.017541.
The shoot apical meristem contains a pool of undifferentiated stem cells and controls initiation of all aerial plant organs. In maize (Zea mays), leaves are formed throughout vegetative development; on transition to floral development, the shoot meristem forms the tassel. Due to the regulated balance between stem cell maintenance and organogenesis, the structure and morphology of the shoot meristem are constrained during vegetative development. Previous work identified loci controlling meristem architecture in a recombinant inbred line population. The study presented here expanded on this by investigating shoot apical meristem morphology across a diverse set of maize inbred lines. Crosses of these lines to common parents showed varying phenotypic expression in the F1, with some form of heterosis occasionally observed. An investigation of meristematic growth throughout vegetative development in diverse lines linked the timing of reproductive transition to flowering time. Phenotypic correlations of meristem morphology with adult plant traits showed an association between the meristem and flowering time, leaf shape, and yield traits, revealing links between the control and architecture of undifferentiated and differentiated plant organs. Finally, quantitative trait loci mapping was utilized to map the genetic architecture of these meristem traits in two divergent populations. Control of meristem architecture was mainly population-specific, with 15 total unique loci mapped across the two populations with only one locus identified in both populations.
茎尖分生组织包含一群未分化的干细胞，并控制着所有地上植物器官的起始。在玉米（Zea mays）中，叶片在整个营养生长发育过程中形成；在向生殖发育转变时，茎尖分生组织形成雄穗。由于干细胞维持和器官发生之间的平衡受到调控，茎尖分生组织的结构和形态在营养生长发育过程中受到限制。先前的研究在一个重组自交系群体中鉴定出了控制分生组织结构的基因座。本文所呈现的研究通过调查一系列不同玉米自交系的茎尖分生组织形态，对此进行了拓展。这些品系与共同亲本的杂交在F1代中表现出不同的表型表达，偶尔会观察到某种形式的杂种优势。对不同品系营养生长发育过程中分生组织生长的研究将生殖转变的时间与开花时间联系起来。分生组织形态与成年植株性状的表型相关性表明，分生组织与开花时间、叶片形状和产量性状之间存在关联，揭示了未分化和已分化植物器官的控制与结构之间的联系。最后，利用数量性状基因座定位来绘制这两个不同群体中这些分生组织性状的遗传结构图谱。分生组织结构的控制主要是群体特异性的，在两个群体中总共定位了15个独特的基因座，两个群体中仅鉴定出一个共同的基因座。
