biostudies-literatureLi MNatural Science Foundation of Shaanxi Province of ChinaNational Natural Science Foundation of China134https://www.ebi.ac.uk/biostudies/studies/S-EPMC8775259biostudies-literatureUnknown13(1)Wall-associated kinase (WAK) and WAK-like kinase (WAKL) are receptor-like kinases (RLKs), which play important roles in signal transduction between the cell wall and the cytoplasm in plants. WAK/WAKLs have been studied in many plants, but were rarely studied in the important economic walnut tree. In this study, 27 and 14 WAK/WAKL genes were identified in Juglans regia and its wild related species Juglans mandshurica, respectively. We found tandem duplication might play a critical role in the expansion of WAK/WAKL gene family in J. regia, and most of the WAK/WAKL homologous pairs underwent purified selection during evolution. All WAK/WAKL proteins have the extracellular WAK domain and the cytoplasmic protein kinase domain, and the latter was more conserved than the former. Cis-acting elements analysis showed that WAK/WAKL might be involved in plant growth and development, plant response to abiotic stress and hormones. Gene expression pattern analysis further indicated that most WAK/WAKL genes in J. regia might play a role in the development of leaves and be involved in plant response to biotic stress. Our study provides a new perspective for the evolutionary analysis of gene families in tree species and also provides potential candidate genes for studying WAK/WAKL gene function in walnuts.GenesIdentification and Characterization of Wall-Associated Kinase (WAK) and WAK-like (WAKL) Gene Family in Juglans regia and Its Wild Related Species Juglans mandshurica.PMC877525932070372 and 41471038ZSK20180092019JM-008Liu HOu MZhao PMa JYe HLi MfalseIdentification and Characterization of Wall-Associated Kinase (WAK) and WAK-like (WAKL) Gene Family in Juglans regia and Its Wild Related Species Juglans mandshurica.Wall-associated kinase (WAK) and WAK-like kinase (WAKL) are receptor-like kinases (RLKs), which play important roles in signal transduction between the cell wall and the cytoplasm in plants. WAK/WAKLs have been studied in many plants, but were rarely studied in the important economic walnut tree. In this study, 27 and 14 WAK/WAKL genes were identified in Juglans regia and its wild related species Juglans mandshurica, respectively. We found tandem duplication might play a critical role in the expansion of WAK/WAKL gene family in J. regia, and most of the WAK/WAKL homologous pairs underwent purified selection during evolution. All WAK/WAKL proteins have the extracellular WAK domain and the cytoplasmic protein kinase domain, and the latter was more conserved than the former. Cis-acting elements analysis showed that WAK/WAKL might be involved in plant growth and development, plant response to abiotic stress and hormones. Gene expression pattern analysis further indicated that most WAK/WAKL genes in J. regia might play a role in the development of leaves and be involved in plant response to biotic stress. Our study provides a new perspective for the evolutionary analysis of gene families in tree species and also provides potential candidate genes for studying WAK/WAKL gene function in walnuts.2022-01-01T00:00:00Z2022 Jan2024-11-19T15:09:15.844Z2022-02-11T15:51:50.398ZS-EPMC87752593505247410.3390/genes13010134