Department of Molecular Plant Physiology, Utrecht University, 3584 CH Utrecht, The Netherlands.
Proc Natl Acad Sci U S A. 2010 Mar 2;107(9):4264-9. doi: 10.1073/pnas.1000410107. Epub 2010 Feb 9.
Timing of germination is presumably under strong natural selection as it determines the environmental conditions in which a plant germinates and initiates its postembryonic life cycle. To investigate how seed dormancy is controlled, quantitative trait loci (QTL) analyses has been performed in six Arabidopsis thaliana recombinant inbred line populations by analyzing them simultaneously using a mixed model QTL approach. The recombinant inbred line populations were derived from crosses between the reference accession Landsberg erecta (Ler) and accessions from different world regions. In total, 11 delay of germination (DOG) QTL have been identified, and nine of them have been confirmed by near isogenic lines (NILs). The absence of strong epistatic interactions between the different DOG loci suggests that they affect dormancy mainly by distinct genetic pathways. This was confirmed by analyzing the transcriptome of freshly harvested dry seeds of five different DOG NILs. All five DOG NILs showed discernible and different expression patterns compared with the expression of their genetic background Ler. The genes identified in the different DOG NILs represent largely different gene ontology profiles. It is proposed that natural variation for seed dormancy in Arabidopsis is mainly controlled by different additive genetic and molecular pathways rather than epistatic interactions, indicating the involvement of several independent pathways.
萌发时间想必受到强烈的自然选择的影响，因为它决定了植物萌发和开始其胚胎后生命周期的环境条件。为了研究种子休眠是如何被控制的，通过使用混合模型 QTL 方法同时对来自 6 个拟南芥重组自交系群体的 QTL 进行了分析。重组自交系群体是由参考品系 Landsberg erecta（Ler）与来自不同世界区域的品系之间的杂交产生的。总共鉴定出 11 个延迟萌发（DOG）QTL，其中 9 个已经通过近等基因系（NIL）得到了确认。不同 DOG 位点之间没有强烈的上位性相互作用，这表明它们主要通过不同的遗传途径影响休眠。这通过分析五个不同 DOG NIL 的新鲜收获干种子的转录组得到了证实。与它们的遗传背景 Ler 的表达相比，所有五个 DOG NIL 都表现出明显不同的表达模式。在不同的 DOG NIL 中鉴定出的基因代表了很大不同的基因本体论图谱。因此，拟南芥种子休眠的自然变异主要由不同的加性遗传和分子途径控制，而不是由上位性相互作用控制，这表明涉及几个独立的途径。
