Identification and characterization of CSE family members in cucumber reveals CsCSE5, a positive regulator of pathogen resistance

Abstract

Abstract Caffeoyl shikimate esterase (CSE), a key enzyme in the lignin biosynthetic pathway, has recently been characterized to play a key role in defense against pathogenic infection in plants. However, a systematic analysis of the CSE gene family in cucumber (Cucumis sativus) has not yet been conducted. Here, we identified eight CsCSEgenes from the cucumber genome via bioinformatic analyses, and these genes were unevenly distributed on chromosomes 1, 3, 4, and 5. Results from multiple sequence alignment indicated that the CsCSE proteins had CSE activity. Phylogenetic analysis of gene structure and protein motifs revealed the conservation and diversity of the CsCSE gene family. Collinearity analysis showed that CsCSEgenes had high homology with CSE genes in Benincasa hispida. Cis-acting element analysis of the promoters suggested that CsCSE genes might play important roles in growth, development, and stress tolerance. Expression pattern analysis indicated that CsCSE5 might be involved in regulating the resistance of cucumber to pathogens. Functional verification data confirmed that CsCSE5 positively regulates the resistance of cucumber to Podosphaera xanthii and Corynespora cassiicola. The results of our study provide information that will aid the genetic improvement of resistant cucumber varieties.