Genome-wide identification, characterization, and transcriptional analysis of the metacaspase gene family in cucumber (Cucumis sativus)

Abstract

Metacaspase (MC), a family of caspase-like proteins, plays vital roles in regulating programmed cell death (PCD) during development and in response to stresses in plants. In this study, five MC genes (designated as CsMC1 to CsMC5) were identified in the cucumber (Cucumis sativus) genome. Sequence analysis revealed that CsMC1–CsMC3 belong to type I MC proteins, while CsMC4 and CsMC5 are type II MC proteins. Phylogenetic tree and conserved motif analysis of MC proteins indicated that these proteins can be classified into two groups, which are correlated with the types of these MC proteins. Gene structure analysis demonstrated that type I CsMC genes contain 4–7 introns, while all type II CsMC genes harbor one intron. In addition, many hormone-, stress-, and development-related cis-elements were identified in the promoter regions of CsMC genes. Expression analysis using RNA-seq data revealed that CsMC genes have distinct expression patterns in various tissues and developmental stages. qRT-PCR results showed that the transcript levels of CsMC genes could be regulated by various abiotic stresses such as NaCl, PEG, and cold. These results demonstrate that the cucumber MC gene family may function in tissue development and plant stress responses.