An organ-specific transcriptomic atlas of the medicinal plant Bletilla striata: Protein-coding genes, microRNAs, and regulatory networks.

As one of the important species belonging to the Bletilla genus of Orchidaceae, Bletilla striata (Thunb.) Rchb. f., possesses both ornamental and medicinal values. Its dried tubers are used as a traditional Chinese medicine, and several secondary metabolites have been indicated to be the active ingredients. However, the molecular mechanisms related to the regulation of secondary metabolism have not been characterized in B. striata. In this study, integrated analysis of RNA sequencing (RNA-seq), small RNA sequencing (sRNA-seq), and degradome sequencing (degradome-seq) data from three organs (leaf, root, and tuber) of B. striata provided us with a comprehensive view of the microRNA (miRNA)-mediated regulatory network. Firstly, based on the RNA-seq data, the organ-specific expression patterns of the protein-coding genes, especially for those related to secondary metabolism, were investigated. Secondly, 342 conserved miRNA candidates were identified from B. striata. These miRNAs were assigned to 88 families, some of which were selected for expression pattern analysis. Additionally, 31 hairpin-structured precursors encoding 23 novel miRNAs were uncovered from the transcriptome assembly. Thirdly, based on the degradome signatures, 1,142 validated miRNA-target pairs (involving 167 conserved miRNAs and six novel miRNAs and 51 target genes) were included in the regulatory network. Organ-specific expression level comparison between the miRNAs and their targets revealed some interesting miRNA-target pairs. Fourthly, some valuable subnetworks were extracted for further functional studies. Additionally, some regulatory pathways were indicated to be monocot specific. Summarily, our results lay a solid basis for in-depth studies on the regulatory mechanisms underlying the production of the medicinal ingredients in B. striata.

RNA-, sRNA-, and degradome-seq were performed for three organs of B. striata. Organ-specific expression patterns of the protein-coding genes were analyzed. A total of 365 miRNAs were identified and subject to expression pattern analysis. A total of 1,142 miRNA-target pairs were validated for network construction. Some miRNA-mediated regulatory pathways were indicated to be monocot specific.

Organ-specific, integrated omics data-based study on the metabolic pathways of the medicinal plant Bletilla striata (Orchidaceae).

BACKGROUND: Bletilla striata is one of the important species belonging to the Bletilla genus of Orchidaceae. Since its extracts have an astringent effect on human tissues, B. striata is widely used for hemostasis and healing. Recently, some other beneficial effects have also been uncovered, such as antioxidation, antiinflammation, antifibrotic, and immunomodulatory activities. As a key step towards a thorough understanding on the medicinal ingredient production in B. striata, deciphering the regulatory codes of the metabolic pathways becomes a major task. RESULTS: In this study, three organs (roots, tubers and leaves) of B. striata were analyzed by integrating transcriptome sequencing and untargeted metabolic profiling data. Five different metabolic pathways, involved in polysaccharide, sterol, flavonoid, terpenoid and alkaloid biosynthesis, were investigated respectively. For each pathway, the expression patterns of the enzyme-coding genes and the accumulation levels of the metabolic intermediates were presented in an organ-specific way. Furthermore, the relationships between enzyme activities and the levels of the related metabolites were partially inferred. Within the biosynthetic pathways of polysaccharides and flavonoids, long-range phytochemical transportation was proposed for certain metabolic intermediates and/or the enzymes. CONCLUSIONS: The data presented by this work could strengthen the molecular basis for further studies on breeding and medicinal uses of B. striata.

Osthole inhibits histamine-dependent itch via modulating TRPV1 activity.

Osthole, an active coumarin isolated from Cnidium monnieri (L.) Cusson, has long been used in China as an antipruritic herbal medicine; however, the antipruitic mechanism of osthole is unknown. We studied the molecular mechanism of osthole in histamine-dependent itch by behavioral test, Ca(2+) imaging, and electrophysiological experiments. First, osthole clearly remitted the scratching behaviors of mice induced with histamine, HTMT, and VUF8430. Second, in cultured dorsal root ganglion (DRG) neurons, osthole showed a dose-dependent inhibitory effect to histamine. On the same neurons, osthole also decreased the response to capsaicin and histamine. In further tests, the capsaicin-induced inward currents were inhibited by osthole. These results revealed that osthole inhibited histamine-dependent itch by modulating TRPV1 activity. This study will be helpful in understanding how osthole exerts anti-pruritus effects and suggests that osthole may be a useful treatment medicine for histamine-dependent itch.

[Oil content of Pyracantha seeds and its relations to soil nutrients in northwestern Hunan Province].

Pyracantha seeds were collected from five habitats in the Karst region of northwestern Hunan Province, and the oil content and its components were determined, with their relations to soil nutrients studied. The results showed that soil total P had positive correlation with the linolic acid in P. fortuneana seed oil, while other soil nutrients had no correlations with the fat acids in the oil. The vitamin E in seed oil had significant positive correlations with soil total Ca and total Mg. The P. fortuneana seeds in test region had the maximum oil content of 5.9%, and the average vitamin E content of 9.9 g x kg(-1). The relative contents of linolic acid, oleic acid and palmic acid were 63.7%, 20.8% and 13.2%, respectively.