Screening and evaluation of adventitious root lines of Panax notoginseng by morphology, gene expression, and metabolite profiles

Characteristics and diversity of endophytic bacteria in Panax notoginseng under high temperature analysed using full-length 16S rRNA sequencing

Panax notoginseng is a traditional Chinese medicinal herb with diverse properties that is cultivated in a narrow ecological range because of its sensitivity to high temperatures. Endophytic bacteria play a prominent role in plant response to climate warming. However, the endophytic bacterial structures in P. notoginseng at high temperatures are yet unclear. In the present study, the diversity and composition of the endophytic bacterial community, and their relationships with two P. notoginseng plants with different heat tolerance capacities were compared using the full-length 16S rRNA PacBio sequencing system. The results revealed that the diversity and richness of endophytic bacteria were negatively associated with the heat tolerance of P. notoginseng. Beneficial Cyanobacteria, Rhodanobacter and Sphingomonas may be recruited positively by heat-tolerant plants, while higher amounts of adverse Proteobacteria such as Cellvibrio fibrivorans derived from soil destructed the cellular protective barriers of heat-sensitive plants and caused influx of pathogenic bacteria Stenotrophomonas maltophilia. Harmonious and conflicting bacterial community was observed in heat-tolerant and heat-sensitive P. notoginseng, respectively, based on the co-occurrence network. Using functional gene prediction of metabolism, endophytic bacteria have been proposed to be symbiotic with host plants; the bacteria improved primary metabolic pathways and secondary metabolite production of plants, incorporated beneficial endophytes, and combated adverse endophytes to prompt the adaptation of P. notoginseng to a warming environment. These findings provided a new perspective on the function of endophytes in P. notoginseng adaptation to high temperatures, and could pave the way for expanding the cultivable range of P. notoginseng.

Recent Advances in Traditional Chinese Medicine for Treatment of Podocyte Injury

Podocyte is also called glomerular epithelial cell, which has been considered as the final gatekeeper of glomerular filtration barrier (GFB). As a major contributor to proteinuria, podocyte injury underlies a variety of glomerular diseases and becomes the challenge to patients and their families in general. At present, the therapeutic methods of podocyte injury mainly include angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, steroid and immunosuppressive medications. Nevertheless, the higher cost and side effects seriously disturb patients with podocyte injury. Promisingly, traditional Chinese medicine (TCM) has received an increasing amount of attention from different countries in the treatment of podocyte injury by invigorating spleen and kidney, clearing heat and eliminating dampness, as well enriching qi and activating blood. Therefore, we searched articles published in peer-reviewed English-language journals through Google Scholar, PubMed, Web of Science, and Science Direct. The protective effects of active ingredients, herbs, compound prescriptions, acupuncture and moxibustion for treatment of podocyte injury were further summarized and analyzed. Meanwhile, we discussed feasible directions for future development, and analyzed existing deficiencies and shortcomings of TCM in the treatment of podocyte injury. In conclusion, this paper shows that TCM treatments can serve as promising auxiliary therapeutic methods for the treatment of podocyte injury.

Endophytes, biotransforming microorganisms, and engineering microbial factories for triterpenoid saponins production

Triterpenoid saponins are structurally diverse secondary metabolites. They are the main active ingredient of many medicinal plants and have a wide range of pharmacological effects. Traditional production of triterpenoid saponins, directly extracted from cultivated plants, cannot meet the rapidly growing demand of pharmaceutical industry. Microorganisms with triterpenoid saponins production ability (especially Agrobacterium genus) and biotransformation ability, such as fungal species in Armillaria and Aspergillus genera and bacterial species in Bacillus and Intestinal microflora, represent a valuable source of active metabolites. With the development of synthetic biology, engineering microorganisms acquired more potential in terms of triterpenoid saponins production. This review focusses on potential mechanisms and the high yield strategies of microorganisms with inherent production or biotransformation ability of triterpenoid saponins. Advances in the engineering of microorganisms, such as Saccharomyces cerevisiae, Yarrowia lipolytica, and Escherichia coli, for the biosynthesis triterpenoid saponins de novo have also been reported. Strategies to increase the yield of triterpenoid saponins in engineering microorganisms are summarized following four aspects, that is, introduction of high efficient gene, optimization of enzyme activity, enhancement of metabolic flux to target compounds, and optimization of fermentation conditions. Furthermore, the challenges and future directions for improving the yield of triterpenoid saponins biosynthesis in engineering microorganisms are discussed.

Composition and function of rhizosphere microbiome of Panax notoginseng with discrepant yields

Background

Panax notoginseng is a highly valuable medicinal plant. Reduced P. notoginseng yield is a common and serious problem that arises in a continuous cropping system. Variation in the composition and function of soil microbial community is considered the primary cause of yield reduction.

Methods

This study used shotgun metagenomic sequencing approaches to describe the taxonomic and functional features of P. notoginseng rhizosphere microbiome and screen microbial taxa and functional traits related to yields.

Results

At the family and genus level, a total of 43 families and 45 genera (relative abundance > 0.1%) were obtained, and the correlation with the yield of P. notoginseng was further analyzed. Nitrosomonadaceae, Xanthomonadaceae, Mycobacterium and Arthrobacter that were enriched in soils with higher yields were positively correlated with P. notoginseng yields, thereby suggesting that they might increase yields. Negative correlation coefficients indicated that Xanthobacteraceae, Caulobacteraceae, Oxalobacteraceae, Chitinophagaceae, Sphingomonas, Hyphomicrobium, Variovorax and Phenylobacterium might be detrimental to P. notoginseng growth. A total of 85 functional traits were significantly (P < 0.05) correlated with P. notoginseng yields. Functional traits, likely steroid biosynthesis and MAPK signaling pathway were positively correlated with P. notoginseng yields. In contrast, functional traits, such as bacterial secretion system, ABC transporters, metabolism of xenobiotics by cytochrome P450 and drug metabolism–cytochrome P450, were negatively associated with yields.

Conclusions

This study describes an overview of the rhizosphere microbiome of P. notoginseng with discrepant yields and identifies the taxa and functional traits related to yields. Our results provide valuable information to guide the isolation and culture of potentially beneficial microorganisms and to utilize the power of the microbiome to increase plant yields in a continuous cropping system.