[Identification of key enzyme genes involved in biosynthesis pathways of lignan and lignin in Eucommia ulmoides based on transcriptome assembly].

Lignan is the main medicinal component of Eucommia ulmoides, and lignin is involved in the defense of plants against diseases and insect pests.They are synthesized from coniferyl alcohol with the help of dirigent(DIR) and peroxidase(POD), respectively.In this study, transcriptome assembly of stems and leaves of E.ulmoides was performed, yielding 112 578 unigenes.Among them, 70 459 were annotated in seven databases.A total of 59 unigenes encodes 11 key enzymes in the biosynthesis pathways of lignin and lignin, of which 11 encode POD and 8 encode DIR.A total of 13 unigenes encoding transcription factors are involved in phenylpropanoid metabolism. Compared with leaves of E.ulmoides, 7 575 unigenes were more highly expressed in stems, of which 462 were involved in phenylpropanoid biosynthesis.Our results extend the public transcriptome dataset of E.ulmoides, which provide valuable information for the analysis of biosynthesis pathways of lignan and lignin in E.ulmoides and lay a foundation for further study on the functions and regulation mechanism of key enzymes in lignan and lignin biosynthesis pathways.

[Identification of key enzyme genes involved in biosynthesis of steroidal saponins and analysis of biosynthesis pathway in Polygonatum cyrtonema].

Steroidal saponins, which are the characteristic and main active constituents of Polygonatum, exhibit a broad range of pharmacological functions, such as regulating blood sugar, preventing cardiovascular and cerebrovascular diseases and anti-tumor. In this study, we performed RNA sequencing(RNA-Seq) analysis for the flowers, leaves, roots, and rhizomes of Polygonatum cyrtonema using the BGISEQ-500 platform to understand the biosynthesis pathway of steroidal saponins and study their key enzyme genes. The assembly of transcripts for four tissues generated 129 989 unigenes, of which 88 958 were mapped to several public databases for functional annotation, 22 813 unigenes were assigned to 53 subcategories and 64 877 unigenes were annotated to 136 pathways in KEGG database. Furthermore, 502 unigenes involved in the biosynthesis pathway of steroidal saponins were identified, of which 97 unigenes encoding 12 key enzymes. Cycloartenol synthase, the first key enzyme in the pathway of phytosterol biosynthesis, showed conserved catalytic domain and substrate binding domain based on sequence analysis and homology modeling. Differentially expressed genes(DEGs) were identified in rhizomes as compared to other tissues(flowers, leaves or roots).The 2 437 unigenes annotated by KEGG showed rhizome-specific expression, of which 35 unigenes involved in the biosynthesis of steroidal saponins. Our results greatly extend the public transcriptome dataset of Polygonatum and provide valuable information for the identification of candidate genes involved in the biosynthesis of steroidal saponins and other important secondary metabolites.

[Transcriptome analysis of venom gland and identification of functional genes for snake venom protein in Agkistrodon acutus].

Agkistrodon acutus is a traditional Chinese herb medicine which has immunological regulation,anti-tumor,anti-inflammatory and analgesic effects,which is mainly used for the treatment of rheumatoid arthritis,ankylosing spondylitis,sjogren's syndrome and tumors. In order to excavate more important functional genes from A. acutus,the transcriptome of the venom gland was sequenced by the Illumina Hi Seq 4000,and 32 862 unigenes were assembled. Among them,26 589 unigenes were mapped to least one public database. 2 695 unigenes were annotated and assigned to 62 TF families,and 5 920 SSR loci were identified. The majority of mapped unigenes was from Protobothrops mucrosquamatus in the NR database,which revealed their closest homology. Three secretory phospholipase A_2 with different amino acid sequences showed similar spatial structures and all had well-conserved active sites. The 3 D structural models of C-type lectin showed conserved glycosylation binding sites( Asn45). This study will lay the foundation for the further study of the function of snake venom protein,and promoting the development and utilization of genome resources from A. acutus.

Comparative transcriptomic analysis reveals the regulatory mechanisms of catechins synthesis in different cultivars of Camellia sinensis.

Camellia sinensis (L.) O. Kuntze is used to produce tea, a beverage consumed worldwide. Catechins are major medically active components of C. sinensis and can be used clinically to treat hyperglycaemia, hypertension, and cancer. In this study, we aimed to identify the genes involved in catechins biosynthesis. To this end, we analysed transcriptome data from two different cultivars of C. sinensis using DNBSEQ technology. In total,47,717 unigenes were obtained from two cultivars of C. sinensis, of which 9429 were predicted as new unigenes. In our analyses of the Kyoto Encyclopedia of Genes and Genomes database, 212 unigenes encoding 13 key enzymes involved in catechins biosynthesis were identified; the structures of leucoanthocyanidin reductase and anthocyanidin reductase were spatially modelled. Some of these key enzymes were verified by real-time quantitative polymerase chain reaction, and multiple genes encoding plant resistance proteins or transcription factors were identified and analysed. Furthermore, two microRNAs involved in the regulation of catechins biosynthesis were explored. Differentially expressed genes involved in the flavonoid biosynthesis pathway were identified from pairwise comparisons of genes from different cultivars of tea plants. Overall, our findings expanded the number of publicly available transcript datasets for this valuable plant species and identified candidate genes related to the biosynthesis of C. sinensis catechins, thereby establishing a foundation for further in-depth studies of catechins biosynthesis in varieties or cultivars of C. sinensis.