Beyond cyanogenesis: Temperature gradients drive environmental adaptation in North American white clover ( Trifolium repens L.)

作者：Wen‐Hsi Kuo, Limei Zhong, Sara J. Wright, David M. Goad, Kenneth M. Olsen · 发表于：Molecular Ecology · 年份：2024 · DOI：10.1111/mec.17484 · 被引用次数：11 · 研究领域：Cassava research and cyanide、Agronomic Practices and Intercropping Systems、Ruminant Nutrition and Digestive Physiology

Species that repeatedly evolve phenotypic clines across environmental gradients have been highlighted as ideal systems for characterizing the genomic basis of local environmental adaptation. However, few studies have assessed the importance of observed phenotypic clines for local adaptation: conspicuous traits that vary clinally may not necessarily be the most critical in determining local fitness. The present study was designed to fill this gap, using a plant species characterized by repeatedly evolved adaptive phenotypic clines. White clover is naturally polymorphic for its chemical defence cyanogenesis (HCN release with tissue damage); climate-associated cyanogenesis clines have evolved throughout its native and introduced range worldwide. We performed landscape genomic analyses on 415 wild genotypes from 43 locations spanning much of the North American species range to assess the relative importance of cyanogenesis loci vs. other genomic factors in local climatic adaptation. We find clear evidence of local adaptation, with temperature-related climatic variables best describing genome-wide differentiation between sampling locations. The same climatic variables are also strongly correlated with cyanogenesis frequencies and gene copy number variations (CNVs) at cyanogenesis loci. However, landscape genomic analyses indicate no significant contribution of cyanogenesis loci to local adaptation. Instead, several genomic regions containing promising candidate genes for plant res...