Suter Léonie, Rüegg Marlene, Zemp Niklaus, Hennig Lars, Widmer Alex
Eidgenössisch Technische Hochschule Zürich, Institute of Integrative Biology, 8092 Zurich, Switzerland (L.S., M.R., N.Z., A.W.); andDepartment of Plant Biology, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, SE-75007 Uppsala, Sweden (L.H.).
Eidgenössisch Technische Hochschule Zürich, Institute of Integrative Biology, 8092 Zurich, Switzerland (L.S., M.R., N.Z., A.W.); andDepartment of Plant Biology, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, SE-75007 Uppsala, Sweden (L.H.)
Plant Physiol. 2014 Dec;166(4):1928-42. doi: 10.1104/pp.114.247346. Epub 2014 Oct 22.
Steep environmental gradients provide ideal settings for studies of potentially adaptive phenotypic and genetic variation in plants. The accurate timing of flowering is crucial for reproductive success and is regulated by several pathways, including the vernalization pathway. Among the numerous genes known to enable flowering in response to vernalization, the most prominent is FLOWERING LOCUS C (FLC). FLC and other genes of the vernalization pathway vary extensively among natural populations and are thus candidates for the adaptation of flowering time to environmental gradients such as altitude. We used 15 natural Arabidopsis (Arabidopsis thaliana) genotypes originating from an altitudinal gradient (800-2,700 m above sea level) in the Swiss Alps to test whether flowering time correlated with altitude under different vernalization scenarios. Additionally, we measured the expression of 12 genes of the vernalization pathway and its downstream targets. Flowering time correlated with altitude in a nonlinear manner for vernalized plants. Flowering time could be explained by the expression and regulation of the vernalization pathway, most notably by AGAMOUS LIKE19 (AGL19), FLOWERING LOCUS T (FT), and FLC. The expression of AGL19, FT, and VERNALIZATION INSENSITIVE3 was associated with altitude, and the regulation of MADS AFFECTING FLOWERING2 (MAF2) and MAF3 differed between low- and high-altitude genotypes. In conclusion, we found clinal variation across an altitudinal gradient both in flowering time and the expression and regulation of genes in the flowering time control network, often independent of FLC, suggesting that the timing of flowering may contribute to altitudinal adaptation.
陡峭的环境梯度为研究植物潜在的适应性表型和遗传变异提供了理想的环境。开花的准确时间对于繁殖成功至关重要，并且受多种途径调控，包括春化途径。在众多已知能响应春化作用而促进开花的基因中，最突出的是开花位点C（FLC）。FLC和春化途径中的其他基因在自然种群中差异很大，因此是开花时间适应海拔等环境梯度的候选基因。我们使用了来自瑞士阿尔卑斯山海拔梯度（海拔800 - 2700米）的15种天然拟南芥（Arabidopsis thaliana）基因型，来测试在不同春化条件下开花时间是否与海拔相关。此外，我们测量了春化途径及其下游靶点的12个基因的表达。对于经过春化处理的植株，开花时间与海拔呈非线性相关。开花时间可以通过春化途径的表达和调控来解释，最显著的是由类AGAMOUS19（AGL19）、开花位点T（FT）和FLC来解释。AGL19、FT和春化不敏感3（VERNALIZATION INSENSITIVE3）的表达与海拔相关，并且低海拔和高海拔基因型之间，影响开花的MADS2（MADS AFFECTING FLOWERING2，MAF2）和MAF3的调控存在差异。总之，我们发现在海拔梯度上，开花时间以及开花时间控制网络中基因的表达和调控都存在渐变变异，且通常与FLC无关，这表明开花时间可能有助于海拔适应性。
