RNA sequencing-based exploration of the effects of blue laser irradiation on mRNAs involved in functional metabolites of D. officinales

Dendrobium officinale Kimura et Migo (D. officinale) has promising lung moisturizing, detoxifying, and immune boosting properties. Light is an important factor influencing functional metabolite synthesis in D. officinale. The mechanisms by which lasers affect plants are different from those of ordinary light sources; lasers can effectively address the shortcomings of ordinary light sources and have significant interactions with plants. Different light treatments (white, blue, blue laser) were applied, and the number of red leaves under blue laser was greater than that under blue and white light. RNA-seq technology was used to analyze differences in D. officinale under different light treatments. The results showed 465, 2,107 and 1,453 differentially expressed genes (DEGs) in LB-B, LB-W and W-B, respectively. GO, KEGG and other analyses of DEGs indicated that D. officinale has multiple blue laser response modes. Among them, the plasma membrane, cutin, suberine and wax biosynthesis, flavone and flavonol biosynthesis, heat shock proteins, etc. play central roles. Physiological and biochemical results verified that blue laser irradiation significantly increases POD, SOD, and PAL activities in D. officinale. The functional metabolite results showed that blue laser had the greatest promoting effect on total flavonoids, polysaccharides, and alkaloids. qPCR verification combined with other results suggested that CRY DASH, SPA1, HY5, and PIF4 in the blue laser signal transduction pathway affect functional metabolite accumulation in D. officinale through positively regulated expression patterns, while CO16 and MYC2 exhibit negatively regulated expression patterns. These findings provide new ideas for the efficient production of metabolites in D. officinale.