QTL Mapping and RNA-Seq Revealed Loci and Candidate Genes Associated with Cold Tolerance of Wheat Root at Seedling Stage

Objectives: Low-temperature stress has become a key factor severely restricting seedling growth in wheat, highlighting the growing importance of research on low-temperature tolerance in wheat. Most previous studies focused on the aboveground organs, and only a minority specifically targeted the roots. Methods: In this study, a recombinant inbred line population derived from a cross between DH118 and Jinmai 919 was used to dissect the genetic regulatory mechanism underlying root growth and development in wheat seedlings under low-temperature conditions. Results: A total of 9 QTLs associated with low-temperature tolerance coefficient were identified; among them, QCi.saw-2B and QCi.saw-5B were validated to be significantly associated with cold tolerance in a natural population including 289 wheat accessions. Moreover, 13 candidate genes from QTL intervals regulating root growth and development under low-temperature stress were further identified based on RNA sequencing. Conclusions: These results provide a foundation for further exploring the regulatory mechanism of root growth and development in wheat under low-temperature stress.