Genome-wide identification and molecular characterization of CRK gene family in cucumber (Cucumis sativus L.) under cold stress and sclerotium rolfsii infection

Abstract Background The plant cysteine-rich receptor-like kinases (CRKs) are a large family having multiple roles, including defense responses under both biotic and abiotic stress. However, the CRK family in cucumbers (Cucumis sativus L.) has been explored to a limited extent. In this study, a genome-wide characterization of the CRK family has been performed to investigate the structural and functional attributes of the cucumber CRKs under cold and fungal pathogen stress. Results A total of 15 C. sativus CRKs (CsCRKs) have been characterized in the cucumber genome. Chromosome mapping of the CsCRKs revealed that 15 genes are distributed in cucumber chromosomes. Additionally, the gene duplication analysis of the CsCRKs yielded information on their divergence and expansion in cucumbers. Phylogenetic analysis divided the CsCRKs into two clades along with other plant CRKs. Functional predictions of the CsCRKs suggested their role in signaling and defense response in cucumbers. The expression analysis of the CsCRKs by using transcriptome data and via qRT-PCR indicated their involvement in both biotic and abiotic stress responses. Under the cucumber neck rot pathogen, Sclerotium rolfsii infection, multiple CsCRKs exhibited induced expressions at early, late, and both stages. Finally, the protein interaction network prediction results identified some key possible interacting partners of the CsCRKs in regulating cucumber physiological processes. Conclusions The results of this study identified and characterized the CRK gene family in cucumbers. Functional predictions and validation via expression analysis confirmed the involvement of the CsCRKs in cucumber defense response, especially against S. rolfsii. Moreover, current findings provide better insights into the cucumber CRKs and their involvement in defense responses.