Chalcone synthase (CHS) family genes regulate the growth and response of cucumber (Cucumis sativus L.) to Botrytis cinerea and abiotic stresses

The chalcone synthase (CHS) gene family is instrumental not only regulating plant growth and development but fine-tuning plant response to environmental hazards. Despite the growing body of literature, the role of CHS genes in cucumber (Cucumis sativus L.) remains elusive. Herein, we identified 4 CsCHS genes from the cucumber genome database. The evolutionary relationship, gene structure, conserved motifs, proteins interaction and chemical properties highlight the key aspects of CsCHS genes in cucumbers. Evolutionary tree analysis reveals that the CsCHS family is divided into four clades. Moreover, the Gene Ontology (GO) analysis showed that CsCHS genes regulate plant growth and response to various environmental stimuli. Microarray expression data showed that CsCHS genes were expressed in almost all the tested tissues. Additionally, the differential expression patterns of the CsCHS genes were found under salinity stress and hormonal treatments. The qRT-PCR analysis of CsCHS genes under aphid infestation revealed they are key components of plant defense against insect pests. Under waterlogging stress, only the CsCHS3 displayed high expression under naphthalene acetic acid (NAA) and ethylene (ETH). The dual luciferase assay indicated that CsCHS2 effectively binds to the promoters of key stress markers CsERF1 and CsERF3. Our results have provided detailed knowledge regarding the CsCHS gene's influ-ential role in growth and development and also providing the resistive defense in cucumber plants. We believe our study will facilitate the breeding of stress-resilient cultivars, particularly against insect pests and water-logging stress.