Genome-Wide Identification of Fatty Acyl-CoA Reductase (FAR) Genes in Dendrobium catenatum and Their Response to Drought Stress

Dendrobium catenatum is a high-value medicinal plant that is predominantly found in high mountain areas, thriving amidst cliffs and rock crevices. However, its wild resources face constant threats from adverse environmental conditions, especially drought stress. Fatty acyl-CoA reductase (FAR) is crucial in plant drought resistance, but there is a lack of research on FAR genes in D. catenatum. In this study, the FAR family genes were identified from the D. catenatum genome. Their genomic characteristics were investigated using bioinformatics techniques, and their expression patterns in different tissues and under 20% PEG8000 conditions mimicking drought stress were analyzed using quantitative real-time RT-PCR (RT-qPCR). Seven DcFAR genes were identified from the D. catenatum genome. The encoded amino acids range between 377 and 587 aa, with molecular weights between 43.41 and 66.15 kD and isoelectric points between 5.55 and 9.02. Based on the phylogenetic relationships, the FAR family genes were categorized into three subgroups, each with similar conserved sequences and gene structures. The cis-acting elements of the promoter regions were assessed, and the results reveal that the DcFAR upstream promoter region contains multiple stress-related elements, suggesting its potential involvement in abiotic stress responses. The RT-qPCR results show distinct expression patterns of DcFAR genes in various plant tissues. It was observed that the expression of most DcFAR genes was upregulated under drought stress. Among them, the expression levels of DcFAR2, DcFAR3, DcFAR5, and DcFAR7 genes under drought stress were 544-, 193-, 183-, and 214-fold higher compared to the control, respectively. These results indicate that DcFAR2/3/5/7 might play significant roles in D. catenatum drought tolerance. This research offers insight into the function of DcFAR genes and provides theoretical support for breeding drought-resistant D. catenatum varieties.