Research Associate The University of North Carolina at Chapel Hill Carrboro, North Carolina
Body of Abstract: During meiosis, recombination in the form of crossing over (CO) between homologous chromosomes ensures chromosome segregation and creates genetic diversity in gametes. Recombination can be modulated by several extrinsic and intrinsic factors. Moderately elevated temperature has been reported as one of the extrinsic factors that increases CO frequency in Arabidopsis thaliana. However, the mechanism by which temperature influences CO frequency is not well defined. Previously we showed that temperature-driven increases meiotic recombination are mediated by the Type I CO pathway in Arabidopsis. To elucidate the signaling mechanisms involved, we used a visual CO assay system called fluorescent tagged lines (FTLs) to examine the recombination phenotypes of mutants alleles of Actin-Related Protein 6 (ARP6), which encodes part of the SWR1 chromatin remodeling complex (SWR1-C), and Heat Stress Transcription Factor 2 (HSFA2) in two genetic intervals on chromosome 3 (I3a) and chromosome 5 (I5cd). The proteins encoded by both genes are involved in thermosensory response. Our data shows that wild type plants have elevated CO frequencies at higher temperatures, but that arp6 and hsfa2 are unaffected. Furthermore, we used yeast two-hybrid and bimolecular fluorescence complementation (BiFC) assays to show that ARP6 and HSFA2 physically interact. These findings demonstrate that are required for Arabidopsis to be able to modulate meiotic recombination in response to increased temperature.