ANAVACO · Analysis of natural variation for cold tolerance in the model plant species Arabidopsis thaliana

The identification of the genetic variants underlying adaptive traits constitutes one of the major challenges for modern biology. In this proposal we focus on the ability of plants to tolerate low temperatures. The molecular basis of cold tolerance has been widely investigated in crop species since freezing temperatures can severely affect quality, yield and production. Through the use of the model plant species Arabidopsis thaliana a dramatic increase in the understanding of the genetic mechanisms underlying cold tolerance was achieved. However, many questions remain still open with regard to the nature of the genes involved in the response of plants to cold temperatures. In this project an original, interdisciplinary strategy will be adopted to address naturally occurring variation for cold tolerance in A. thaliana. First, with the aim of identifying the genes underlying variation for cold tolerance in A. thaliana, association mapping will be performed, making use of a set of 1300 A. thaliana accessions, genotyped for 250.000 Single Nucleotide Polymorphisms. In contrast to classical linkage mapping, association mapping has the potential to identify single or a few genes. However, it is affected by population structure, which can eventually lead to a high rate of false positives. Therefore, F2 and F3 progenies will be designed, and used in classical linkage mapping to confirm that associations are due to linkage with causative polymorphisms rather than being spurious correlations due to population structure. Second, to elucidate the selective forces to which the loci identified in the association study have been submitted nucleotide variation will be analyzed at the loci as well as at their surrounding genomic regions and compared to the genome-wide polymorphism pattern. Finally, the candidate loci for cold tolerance identified through association mapping will be submitted to functional analyses in order to confirm their implication in cold tolerance.