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.
Project description:Dendrobium huoshanense C.Z. Tang et S.J. Cheng is a perennial epiphytic herb of family Orchidaceae, which main metabolites are polysaccharides, flavonoids, etc. Low temperature is the main environmental factor that limits the growth and development of plants, and even threatens the survival of plants. However, Changes that occur at the molecular level in response to low temperatures are poorly understood in D. huoshanense. To understand the molecular mechanism of cold tolerance, we performed transcriptomic analysis on two time points of 0 d (control group) and 7 d (cold stress group). A total of 37.63 Gb transcriptomic data were generated using the MGI 2000 platform. These reads were assembled into 170,754 transcripts, and 23,724 differentially expressed genes (DEGs) were obtained. Pathway analysis indicated that “flavonoid biosynthesis”, “anthocyanin biosynthesis”, “flavone and flavonol biosynthesis”, and “plant hormone signal transduction” might play a vital role in D. huoshanense responses to cold stress. Several important pathways genes such as genes encoding polysaccharides, flavonoid, and plant hormone-signaling transduction kinase were identified under cold stress. In addition, the contents of mannose and total flavonoids increased under cold stress. Twelve DEGs in polysaccharides, flavonoid, and hormone pathways were selected from transcriptome analysis for quantitative real-time PCR (qRT-PCR) validation. Our results provide a transcriptome database and candidate genes for further study of D. huoshanense cold stress.