Chromosome-level genome assembly and functional characterization of terpene synthases provide insights into the volatile terpenoid biosynthesis of Wurfbainia villosa.

Wurfbainia villosa is a well-known medicinal and edible plant that is widely cultivated in the Lingnan region of China. Its dried fruits (called Fructus Amomi) are broadly used in traditional Chinese medicine for curing gastrointestinal diseases and are rich in volatile terpenoids. Here, we report a high-quality chromosome-level genome assembly of W. villosa with a total size of approximately 2.80 Gb, 42 588 protein-coding genes, and a very high percentage of repetitive sequences (87.23%). Genome analysis showed that W. villosa likely experienced a recent whole-genome duplication event prior to the W. villosa-Zingiber officinale divergence (approximately 11 million years ago), and a recent burst of long terminal repeat insertions afterward. The W. villosa genome enabled the identification of 17 genes involved in the terpenoid skeleton biosynthesis pathway and 66 terpene synthase (TPS) genes. We found that tandem duplication events have an important contribution to the expansion of WvTPSs, which likely drove the production of volatile terpenoids. In addition, functional characterization of 18 WvTPSs, focusing on the TPS-a and TPS-b subfamilies, showed that most of these WvTPSs are multi-product TPS and are predominantly expressed in seeds. The present study provides insights into the genome evolution and the molecular basis of the volatile terpenoids diversity in W. villosa. The genome sequence also represents valuable resources for the functional gene research and molecular breeding of W. villosa.

The miR-155 regulates cytokines expression by SOSC1 signal pathways of fish in vitro and in vivo.

MiR-155 is reported as immune regulated miRNA in mammalian corresponding to immunity, antibacterial and antiviral effects regulation. However, the roles and mechanisms of the miRNA have remained largely undefined. We herein comprehensively investigated the functions of miR-155 in vitro and in vivo by miR-155 mimics, agomir and antagomir in Cyprinus carpio and Ictalurus punctatus, with the target genes in the SOSC1 pathway certified in I. punctatus via luciferase reporter assays. Results showed that the miR-155 regulated the expressions of cytokines, including TNF-α, IFN-γ, IL-1ß, IL-6 and IL-10. Further research confirmed SOSC1 as one of the targets of the miRNA, and the JAK1/STAT3/SOSC1 signal pathway involved in the miR-155 effects on the expression of immune cytokines as well. Additionally, the changes of TLR2 in fish may also be related to miR-155 along with its target SOCS1, and the TLR2/MyD88 pathway may partly participate in the effects of the miR-155 on the cytokines. The research here confirmed that the miR-155 can regulate cytokines expression by SOSC1 signal pathways of fish in vitro and in vivo, which would provide resources for understanding and studying about immune regulation in fish.

Genomic insights into the evolution of flavonoid biosynthesis and O-methyltransferase and glucosyltransferase in Chrysanthemum indicum.

Flavonoids are a class of secondary metabolites widely distributed in plants. Regiospecific modification by methylation and glycosylation determines flavonoid diversity. A rare flavone glycoside, diosmin (luteolin-4'-methoxyl-7-O-glucosyl-rhamnoside), occurs in Chrysanthemum indicum. How Chrysanthemum plants evolve new biosynthetic capacities remains elusive. Here, we assemble a 3.11-Gb high-quality C. indicum genome with a contig N50 value of 4.39 Mb and annotate 50,606 protein-coding genes. One (CiCOMT10) of the tandemly repeated O-methyltransferase genes undergoes neofunctionalization, preferentially transferring the methyl group to the 4'-hydroxyl group of luteolin with ortho-substituents to form diosmetin. In addition, CiUGT11 (UGT88B3) specifically glucosylates 7-OH group of diosmetin. Next, we construct a one-pot cascade biocatalyst system by combining CiCOMT10, CiUGT11, and our previously identified rhamnosyltransferase, effectively producing diosmin with over 80% conversion from luteolin. This study clarifies the role of transferases in flavonoid diversity and provides important gene elements essential for producing rare flavone.