Penthorum chinense Pursh has been used for centuries as an herbal medicine and food in East Asia. The main active substances in P. chinense are galloylated macrocyclic polyphenolic compounds, which have excellent medicinal properties. Galloylation and glycosylation are key steps in the formation of polyphenolic compounds, as the glycosylation of flavonoids is required for the acylation of flavonoid glycosides, and the glycosylation of gallic acid is necessary for its role as an acyl donor. Therefore, glycosylation to generate the acyl donor or acceptor is a core step in the biosynthesis of polyphenolic compounds. However, how this glycosylation occurs in P. chinense is unknown. In this study, we determined that the UDP-glucose transferase PcUGT84A82 mediates the glycosylation of gallic acid and pinocembrin to produce 1-O-Galloyl-β-D-glucose and pinocembroside, respectively. Metabolic profiling of polyphenolic compounds using UHPLC-ESI–Q-TOF/MS revealed high levels of polyphenols in flowers, leaves, and roots, and low levels in stems of P. chinense. We performed isoform-sequencing (Iso-seq) to assemble a full-length transcriptome of P. chinense, from which we identified 58 UGT family members. PcUGT84A82 is highly similar to functional UGTs in other plant species, and PcUGT84A82 transcript levels were positively correlated with the levels of various polyphenolic compounds. We validated the function of PcUGT84A82 via in vitro enzyme assays and transient expression in Nicotiana benthamiana leaves. Subcellular localization tests showed that PcUGT84A82 localizes to the nucleus and cytoplasm. In summary, PcUGT84A82 catalyzes the conversion of gallic acid to 1-O-Galloyl-β-D-glucose as the acyl donor and pinocembrin to pinocembroside as the acyl acceptor, mediating the biosynthesis of galloylated macrocyclic polyphenolic compounds in P. chinense. These findings lay the foundation for elucidating the entire biosynthetic pathway of active polyphenols in this important herbal plant species.

Artemisinin is primarily synthesized and stored in the subepidermal space of the glandular trichomes of Artemisia annua. The augmentation of trichome density has been demonstrated to enhance artemisinin yield. However, existing literature lacks insights into the correlation between the stratum corneum and trichomes. This study aims to unravel the involvement of TrichomeLess Regulator 3 (TLR3), which encodes the transcription factor, in artemisinin biosynthesis and its potential association with the stratum corneum. TLR3 was identified as a candidate gene through transcriptome analysis. The role of TLR3 in trichome development and morphology was investigated using yeast two-hybrid, pull-down analysis, and RNA electrophoresis mobility assay. Our research revealed that TLR3 negatively regulates trichome development. It modulates the morphology of Arabidopsis thaliana trichomes by inhibiting branching and inducing the formation of abnormal trichomes in Artemisia annua. Overexpression of the TLR3 gene disrupts the arrangement of the stratum corneum and reduces artemisinin content. Simultaneously, TLR3 possesses the capacity to regulate stratum corneum development and trichome follicle morphology by interacting with TRICHOME AND ARTEMISININ REGULATOR 1, and CycTL. Consequently, our findings underscore the pivotal role of TLR3 in the development of glandular trichomes and stratum corneum biosynthesis, thereby influencing the morphology of Artemisia annua trichomes.

Plant phenomics aims to perform high-throughput, rapid, and accurate measurement of plant traits, facilitating the identification of desirable traits and optimal genotypes for crop breeding. Salvia miltiorrhiza (Danshen) roots possess remarkable therapeutic effect on cardiovascular diseases, with huge market demands. Although great advances have been made in metabolic studies of the bioactive metabolites, investigation for S. miltiorrhiza roots on other physiological aspects is poor. Here, we developed a framework that utilizes image feature extraction software for in-depth phenotyping of S. miltiorrhiza roots. By employing multiple software programs, S. miltiorrhiza roots were described from 3 aspects: agronomic traits, anatomy traits, and root system architecture. Through K-means clustering based on the diameter ranges of each root branch, all roots were categorized into 3 groups, with primary root-associated key traits. As a proof of concept, we examined the phenotypic components in a series of randomly collected S. miltiorrhiza roots, demonstrating that the total surface of root was the best parameter for the biomass prediction with high linear regression correlation (R² = 0.8312), which was sufficient for subsequently estimating the production of bioactive metabolites without content determination. This study provides an important approach for further grading of medicinal materials and breeding practices.

Isatis indigotica Fort. (Chinese woad) is a species with an ancient and well-documented history as an indigo dye and medicinal plant. It is often confused with Isatis tinctoria L. (European woad), a medicinal plant in Europe. Here, the differences between I. indigotica and I. tinctoria are systematically described. The usage development history, clinical applications and pharmacological activities, and chemical components of I. indigotica are also summarized. Lignans, indole alkaloids, and their corresponding derivatives have been identified as the major active ingredients of I. indigotica and are associated with anti-viral, anti-inflammatory, anti-cancer, and other health-promoting activities. Notable progress has been made in understanding the biosynthetic pathway and regulation mechanism of lignans and indole alkaloids in I. indigotica, the results from which should facilitate the process of targeted metabolic engineering or synthetic biology. Moreover, multiple biotechnology methods such as polyploid breeding and genetic engineering have been used with I. indigotica to result in, for example, greater yields, higher levels of bioactive component accumulation, and enhanced stress tolerance to salt, drought, and insects. Some issues require additional analyses, and suggestions for future research on I. indigotica are also discussed.