Decoding drought tolerance from a genomic approach in <i>Castanea sativa</i> Mill

Climate change, marked by prolonged periods of extreme summer drought coupled with heat, presents a significant challenge for chestnut forests. Genomic insight into drought tolerance in Castanea sativa is essential for enhancing the adaptation of this species to climate change. However, progress in this area has been hindered by the lack of a genome reference. To address this limitation, we developed a comprehensive drought tolerance gene atlas by leveraging publicly available databases and the high homology between the Quercus and Castanea genera. Candidate genes were identified through a mapping approach using short-read sequence databases and validated via Sanger sequencing. Our method enabled the successful reconstruction of coding sequences and the identification of genetic variability in C. sativa. Two genes encoding an oleosin-like protein and a two-component response regulator exhibited significant sequence differences, suggesting their involvement in adaptive stress responses. These genes emerge as promising targets for future research and potential genetic markers for drought tolerance. The resulting gene atlas provides valuable insights into drought tolerance and supports the development of molecular markers for more targeted and effective conservation and breeding strategies.