Identification of yellowhorn(Xanthoceras sorbifolium)WRKY transcription factor family and analysis of abiotic stress response model

WRKY transcription factors are widely distributed in higher plants and play important roles in many biological processes,including stress resistance.The recently published genome sequence of yellowhorn,an oil tree with robust resistance to cold,drought,heat,salt and alkali,provides an excellent opportunity to identify and characterize the entire yellowhorn WRKY protein family and a basis for the study of abiotic stress resistance of WRKY gene family in forest species.In the present comprehensive analysis of WRKY transcription factors in yellowhorn,65 WRKY genes were identified and defined based on their location on the chromosome.According to their structure and phylogenetic relationships,XsWRKY genes clustered into WRKY groupsⅠ-Ⅲ.Segmental duplication events played a significant role in the expansion of WRKY gene family.Furthermore,transcriptomic data and real-time quantitative PCR analysis showed that expression of XsWRKY genes responding to salt and drought stresses and a hormone treatment.We also determined structures of the encoded proteins,c is-elements of the promoter region,and expression patterns.These results provide a foundation for the study of the biological function of WRKY transcription factors in yellowhorn.