Elevational gradients will offer good systems for understanding environmental adaptation of plants because along the gradient environment changes remarkably in a short distance. Solidago virgaurea are widely distributed in Japanese mountain ranges along elevational gradients (0-3000m). Therefore, this species is suitable for elucidating adaptation process in alpine environments, which has not been conscientiously examined.
In this study, we aim to unravel environment adaptation process in alpine by revealing historical population demography and genetic structure of S. virgaurea populations at different elevation in multiple mountain ranges. First, we investigated a phylogeographic pattern of lowland and alpine populations of 16 mountain ranges using chloroplast DNA and nuclear microsatellite markers. As a result, genetic differentiation between lowland and alpine population in a same mountain region was little, suggesting that they have experienced same colonization process by recently range expansion. Second, we estimated detailed genetic structure of S. virgaurea populations along elevational gradient in two mountain regions based on Rad-seq analysis. Genetic similarities largely changed at the timberlines at both mountain regions, indicating that active gene flow occurs among adjacent different elevational populations while local adaptation may occur in alpine populations due to different selection such as light condition.