Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstraße 3, 06466 Gatersleben, Germany.
Plant J. 2012 Aug;71(4):669-83. doi: 10.1111/j.1365-313X.2012.05021.x. Epub 2012 Jun 12.
Heterosis-associated cellular and molecular processes were analyzed in seeds and seedlings of Arabidopsis thaliana accessions Col-0 and C24 and their heterotic hybrids. Microscopic examination revealed no advantages in terms of hybrid mature embryo organ sizes or cell numbers. Increased cotyledon sizes were detectable 4 days after sowing. Growth heterosis results from elevated cell sizes and numbers, and is well established at 10 days after sowing. The relative growth rates of hybrid seedlings were most enhanced between 3 and 4 days after sowing. Global metabolite profiling and targeted fatty acid analysis revealed maternal inheritance patterns for a large proportion of metabolites in the very early stages. During developmental progression, the distribution shifts to dominant, intermediate and heterotic patterns, with most changes occurring between 4 and 6 days after sowing. The highest incidence of heterotic patterns coincides with establishment of size differences at 4 days after sowing. In contrast, overall transcript patterns at 4, 6 and 10 days after sowing are characterized by intermediate to dominant patterns, with parental transcript levels showing the largest differences. Overall, the results suggest that, during early developmental stages, intermediate gene expression and higher metabolic activity in the hybrids compared to the parents lead to better resource efficiency, and therefore enhanced performance in the hybrids.
杂种优势相关的细胞和分子过程在拟南芥 Col-0 和 C24 及其杂种中的种子和幼苗中进行了分析。显微镜检查显示杂种成熟胚器官大小或细胞数量没有优势。播种后 4 天可检测到子叶大小增加。生长杂种优势源于细胞大小和数量的增加，在播种后 10 天得到很好的体现。杂种幼苗的相对生长率在播种后 3 至 4 天之间得到最大增强。全局代谢物分析和靶向脂肪酸分析表明，在早期阶段，大量代谢物具有母系遗传模式。在发育过程中，分布模式转变为优势、中间和杂种模式，大多数变化发生在播种后 4 至 6 天之间。杂种模式出现的最高频率与播种后 4 天大小差异的建立相一致。相比之下，播种后 4、6 和 10 天的整体转录模式以中间到优势模式为特征，亲本转录水平差异最大。总体而言，结果表明，在早期发育阶段，与亲本相比，杂种中中间基因表达和更高的代谢活性导致更好的资源效率，从而提高杂种的性能。
