Cuticle function can be pivotal to plant success in different environments. Yet, the occurrence of intraspecific adjustments in cuticle traits resulting from acclimation or adaptation to different habitats remains poorly understood. Here, we used genetically well-characterised populations of Arabidopsis arenosa to investigate whether cuticle traits were adjusted as part of the parallel evolution from a foothill to an alpine ecotype. Six alpine and six foothill populations, representing at least three independent evolutionary origins of an alpine ecotype, were used in reciprocal transplantation experiments, to investigate cuticle traits at the eco-physiological, biochemical and structural levels. The genetic basis behind these traits was assessed by combining selection scans and differential gene expression analysis. Overall, alpine populations showed reduced cuticular transpiration in conjunction with consistently altered cuticular wax composition, with higher accumulation of two fatty alcohols and two iso-alkanes. Genomic analysis unravelled nine genes associated with cuticular wax metabolism showing allelic differentiation in alpine compared to lowland populations. In silico gene expression analysis revealed differences between ecotypes for several genes related to cuticle metabolism. Repeated ecotypic differentiation in cuticle traits together with the genetic architecture of the alpine ecotype points at an adaptive value of cuticle adjustments for the colonisation of alpine habitats.

• Keywords
• Alpine habitat, Arabidopsis arenosa, adaptation, cuticle, cuticular wax composition, ecotype, parallel evolution,
• MeSH
• Arabidopsis * genetics   physiology   MeSH
• Ecosystem * MeSH
• Ecotype MeSH
• Plant Epidermis * physiology   genetics   MeSH
• Phenotype MeSH
• Quantitative Trait, Heritable * MeSH
• Plant Leaves * physiology   genetics   anatomy & histology   MeSH
• Gene Expression Regulation, Plant MeSH
• Genes, Plant MeSH
• Waxes metabolism   MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Waxes MeSH