Molecular-genetic analysis of trade-offs between vegetative growth and flowering in natural populations of perennial Arabis alpina

多年生植物的生活史通常分为营养生长和开花两个阶段。每一个阶段的持续时间都可以通过遗传变异来改变。生态学研究预测，在生命周期的不同阶段之间存在权衡，因此开花和产生后代的优势因生物量的减少和死亡率的增加而降低。我建议在天然高山种群中研究这种权衡，高山阿拉伯是十字花科植物。在一些种群中，开花的时间和持续时间会发生遗传和表型的变化。在第一阶段，我们在Col du Galibier/Pic Blanc对一个自然种群的表型变异的空间分布进行了密集的测试，并对温室野生植物的后代进行了测试，结果表明，种群的提前开花和延长开花时间具有很强的不对称性，主要发生在较低的海拔。在第二阶段，我建议使用我们已经生成的作图群体来识别在该群体中分离的基因的等位基因变异，并赋予开花时间和开花持续时间的差异。通过对生长在自然种群中的植物进行基因分型并测量它们的寿命，我们将评估开花行为和死亡率之间是否存在相关性。为了测试这一开花性状是否处于局部选择之下，我们将比较开花等位基因与中性变异在整个群体中的分布，测试生长在不同位置的植物的异交频率，并进行相互移植实验。此外，还将测量整个种群的环境参数，试图将选择性制剂与表型差异联系起来。为了推广这些观察，在两个相邻的高山种群和一个瑞典高山种群中启动了类似的研究，这些研究将在第二阶段扩大。这项工作将测试开花开始和持续时间的变化对多年生阿拉比斯高山植物局部适应的重要性。

The life cycles of perennial plants are typically divided into phases of vegetative growth and flowering. The duration of each of these phases can be altered by genetic variation. Ecological studies predict that there are trade-offs between the different phases of the life cycle, so that the advantages of flowering and producing progeny are lowered by resulting reductions in biomass and increases in mortality. I propose to study this trade off in natural alpine populations of perennial Arabis alpina, a member of the Brassicaceae. In several populations genetic and phenotypic variation occur for the time of onset and duration of flowering. In the first phase by intensively testing the spatial distribution of phenotypic variation in one natural population at Col du Galibier / Pic Blanc and testing the progeny of wild plants in the glasshouse, we showed that early onset and extended duration of flowering is strongly asymmetric in the population and occurs mainly at lower altitudes. In the second phase I propose to use mapping populations we have already generated to identify allelic variation at genes segregating in this population and conferring differences in timing and duration of flowering. By genotyping plants growing in the natural population and measuring their longevity, we will assess whether there is a correlation between flowering behavior and mortality. To test whether this flowering trait is under local selection we will compare the distribution of flowering alleles with neutral variation across the population, test the outcrossing frequency of plants growing at different positions and perform reciprocal transplant experiments. Furthermore, environmental parameters will be measured across the population to try to correlate selective agents with phenotypic differences. To generalize the observations, similar studies were initiated in two neighbouring alpine populations and one Swedish population of Arabis alpina, and these will be extended in the second phase. This work will test the importance of variation in flowering onset and duration to local adaptation of perennial Arabis alpina.