Identification and expression analysis of Jr4CLs  gene family based on transcriptome and physiological data in Walnut ( Juglans regia )

Abstract Shoot shriveling severely threat growth and development of deciduous trees in northern hemisphere, its essence is imbalance of water absorption and evaporation in the branches. In this study, the physiological characteristics of 'Xiangling' and 'Liaohe (Liaoning No. 4)' during the overwintering process were studied, and key overwintering periods were selected for transcripome analysis. The results showed that plant hormone metabolism, wax metabolism and lignin metabolism were significantly enriched during the overwintering process. Combined with Jr4CL family analysis, the high-expression gene (Jr4CL44) under drought stress was selected by real-time fluorescence quantitative screening for functional verification. Overexpression of Jr4CL44 can effectively remove the reactive oxygen species produced by drought stress, increase lignin content and up-regulate the expression of related genes to improve the drought resistance of Arabidopsis thaliana. These results indicate that Jr4CL44 plays an important role in plant resistance to drought stress, which laies a foundation for further study on the functions in practice.