Project description:Dendrobium plants are perennial herbs in the family Orchidaceae (Dendrobium Sw.). Due to protocorm can also produce plant-specific useful metabolites, protocorm is becoming a good substitute. MicroRNAs play essential roles in plant growth, development, and the response to environmental stresses, and they are widely used for prediction of molecular functions for biosynthesizing active comportments in medicinal plants. To obtain insight into the function of miRNAs in Dendrobium plants. Illumina sequencing of D. nobile protocorm, D. officinale protocorm and D. nobile leaf were conducted. A total of 439, 412 and 432 miRNAs were identified in three samples, and their expression levels were significantly different. Specially, 2, 12 and 4 specific miRNAs were identified. Through integrated GO and KEGG function annotation, miRNAs mainly involved in metabolic pathways, plant hormone signal transduction, biological regulation and protein binding. AACT, MK, DXR and HDS as important enzymes in synthesizing basic precursor isoprene pyrophosphate (IPP). were predicted controlled by 6 different miRNAs in terpenoid backbone biosynthesis pathway. 26 miRNAs participated in Auxin, Cytoklinine, Abscisic acid, Jasmonic acid and Salicylic acid signal transduction pathway. Our results could provide valuable information about miRNAs involved in terpenoid biosynthesis and plant hormone signal transduction pathway in D. nobile and candidate genes for increasing the yield of dendrobine.