CONICET | Buscador de Institutos y Recursos Humanos

To compare the physiological and genetic characteristics of Arabidopsis thaliana plants growing in South America with those of more extensively-studied geographic regions, we collected A. thaliana plants from four ecologically diverse sites in Patagonia, Argentina. In the wild, these plants had a rapid spring-summer reproductive cycle and exhibited variation in growth morphology. In the lab, the Patagonia plants were less sensitive to red light signaling, had a better temperature compensation mechanism for the circadian rhythm of leaf movement, and exhibited a constitutive shade avoidance response during growth under different light conditions compared to Col-0. They were late-flowering in both long and short photoperiod conditions, but flowered much earlier after vernalization. The vernalization requirement was correlated with FLC expression and could be overcome by growth in constant white light at 10°C. We examined the genetic diversity of Patagonia accessions at a coarse scale relative to 5500 worldwide accessions using a clustering homology analysis of 149 SNPs and at a fine scale using whole-genome sequencing of four Patagonia individuals compared to 80 European accessions. Genome-wide analysis at the coarse scale showed that the Patagonia individuals belonged to the same haplogroup and were most similar to haplogroups from Italy. Comparable results were seen at the fine scale, with site-specific SNPs being rare. We conclude that the Patagonia accessions are a genetically uniform group that likely resulted from anthropogenic introduction from Europe. Although the Patagonia accessions exhibited similar physiological responses to different conditions in the lab, high phenotypic plasticity of Patagonia plants in the wild make this collection useful for characterizing genotype by environment interactions.