CAS Key Laboratory of Soybean Molecular Design Breeding, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, 130102, China.
Shandong Provincial Key Laboratory of Plant Stress, College of Life Sciences, Shandong Normal University, Jinan, 250014, China.
BMC Plant Biol. 2020 Dec 7;20(1):547. doi: 10.1186/s12870-020-02758-w.
Organ shape and size covariation (allometry) factors are essential concepts for the study of evolution and development. Although ample research has been conducted on organ shape and size, little research has considered the correlated variation of these two traits and quantitatively measured the variation in a common framework. The genetic basis of allometry variation in a single organ or among different organs is also relatively unknown.
A principal component analysis (PCA) of organ landmarks and outlines was conducted and used to quantitatively capture shape and size variation in leaves and petals of multiparent advanced generation intercross (MAGIC) populations of Arabidopsis thaliana. The PCA indicated that size variation was a major component of allometry variation and revealed negatively correlated changes in leaf and petal size. After quantitative trait loci (QTL) mapping, five QTLs for the fourth leaf, 11 QTLs for the seventh leaf, and 12 QTLs for petal size and shape were identified. These QTLs were not identical to those previously identified, with the exception of the ER locus. The allometry model was also used to measure the leaf and petal allometry covariation to investigate the evolution and genetic coordination between homologous organs. In total, 12 QTLs were identified in association with the fourth leaf and petal allometry covariation, and eight QTLs were identified to be associated with the seventh leaf and petal allometry covariation. In these QTL confidence regions, there were important genes associated with cell proliferation and expansion with alleles unique to the maximal effects accession. In addition, the QTLs associated with life-history traits, such as days to bolting, stem length, and rosette leaf number, which were highly coordinated with climate change and local adaption, were QTL mapped and showed an overlap with leaf and petal allometry, which explained the genetic basis for their correlation.
This study explored the genetic basis for leaf and petal allometry and their interaction, which may provide important information for investigating the correlated variation and evolution of organ shape and size in Arabidopsis.
器官形状和大小的协变（即异速生长）因素是研究进化和发育的重要概念。尽管已经对器官形状和大小进行了大量研究，但很少有研究考虑到这两个特征的相关变化，并在一个共同的框架中对其变化进行定量测量。单一器官或不同器官之间异速生长变化的遗传基础也相对未知。
对拟南芥多亲本高级世代互交（MAGIC）群体的叶片和花瓣的器官地标和轮廓进行了主成分分析（PCA），并用于定量捕捉叶片和花瓣的形状和大小变化。PCA 表明，大小变化是异速生长变化的主要组成部分，并揭示了叶片和花瓣大小的负相关变化。在进行数量性状位点（QTL）作图后，鉴定出第四片叶的 5 个 QTL、第七片叶的 11 个 QTL 和花瓣大小和形状的 12 个 QTL。这些 QTL 与以前鉴定的 QTL 不同，除了 ER 基因座。还使用异速生长模型来测量叶片和花瓣的异速生长协变，以研究同源器官之间的进化和遗传协调。总共鉴定出与第四片叶和花瓣异速生长协变相关的 12 个 QTL，与第七片叶和花瓣异速生长协变相关的 8 个 QTL。在这些 QTL 置信区间内，有与细胞增殖和扩张相关的重要基因，并且具有最大效应访问体独特的等位基因。此外，与生活史特征相关的 QTL ，如花芽期、茎长和莲座叶数，与气候变化和局部适应高度协调，这些 QTL 也进行了定位，并与叶片和花瓣的异速生长重叠，解释了它们相关性的遗传基础。
本研究探讨了叶片和花瓣异速生长及其相互作用的遗传基础，这可能为研究拟南芥器官形状和大小的相关变化和进化提供重要信息。
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