Genome-wide identification and expression profiling of the BcSNAT family genes and their response to hormones and abiotic stresses in flowering Chinese cabbage

Flowering Chinese cabbage (Brassica rapa ssp. Chinensis var. parachinensis) is an economically important vegetable crop that is widely cultivated in southern China and worldwide. However, plants are sensitive to environmental cues that can significantly reduce crop production. Melatonin is a pineal gland hormone that acts as a plant signalling molecule in abiotic stress tolerance. Serotonin N-acetyltransferase (SNAT) family proteins play a central role in the melatonin biosynthesis pathway and in plant responses to environmental influences. Therefore, this study aimed to identify the SNAT family genes and characterise their functions in flowering Chinese cabbage. To assess the involvement of BcSNAT family genes in abiotic stress, we performed genome-wide characterisation of the BcSNAT family, including the identification of BcSNAT genes, phylogenetic relationships, chromosomal locations, two dimensional (D), and 3D protein structures, subcellular localisation, motif analysis, cis-regulatory elements, expression profiling in different tissues, hormone treatments, and abiotic stress responses. In the flowering Chinese cabbage genome, two SNAT genes were identified (BcSNAT1 and BcSNAT2) and named according to their chromosomal locations. Phylogenetic analysis revealed that the BcSNAT genes were divided into two groups (I and II) and exhibited high homology with other plant species. Numerous cis-elements, including hormone-, stress-, metabolism-, and development-responsive cis-elements, were identified in the promoter analysis of BcSNAT genes. BcSNAT genes were expressed in different tissues of flowering Chinese cabbage and responded to melatonin, hormone treatments, and abiotic stresses. It is anticipated that BcSNAT genes may play an important role in abiotic stress tolerance by activating the melatonin signalling pathway. The results of this study may provide a theoretical foundation for further research on genetic modifications to enhance the production of protected vegetables.