Genome-Wide Identification of the Gene Family in Cucurbitaceae: Clade Identification and Expression Analysis of Genes Under Drought and Salt Stress.

BACKGROUND

The short strand-related sequence (SRS) gene family is a class of plant-specific transcription factors related to a group of genes known as the short internode (SHI) or SRS/STY gene family, which plays important roles in regulating plant growth and development and stress responses. Although the genes have been studied in many plants, in cucurbit crops, they have thus far only been identified in cucumber.

METHODS

In the Cucurbitaceae database from melon (), cucumber (), watermelon (), bottle gourd (), wax gourd (), moschata pumpkin (, and pumpkin (), a total of 60 genes were identified in seven Cucurbitaceae crops, which were classified into three subfamilies.

RESULTS

The same subfamily showed conserved motifs and gene structures. The differences in the number of genes in different Cucurbitaceae crops implied likely gene loss or duplication events during evolution. Analysis of promoter -regulatory elements indicated that these genes may be involved in hormone response, growth and development, and biotic and abiotic stress responses in plants. Most of the genes in melons were expressed in the roots, with a few expressed in the leaves and ovaries. In addition, expression was induced by biotic (wilt and powdery mildew) and abiotic (drought and salt) stresses. Subcellular localization of CmSRS proteins showed predominant expression in the nucleus.

CONCLUSIONS

A total of 60 Cucurbitaceae genes are present in the genomes of seven Cucurbitaceae crops. These cucurbit genes seem to have maintained similar characteristics and functions during the evolutionary process. These results lay the foundation for the study of biological functions of genes in Cucurbitaceae crops.