Structure and function of rhizosphere and root endophyte microbial communities associated with healthy and root rot diseased Panax notoginseng

Abstract

Background: Panax notoginseng (Burkill) F. H. Chen is a Chinese medicinal plant of the Araliaceae family commonly used in the treatment of cardiovascular and cerebrovascular diseases in Asia and elsewhere. To meet an increase in Chinese herbal medicine market demand, most P. notoginseng is planted artificially, and is vulnerable to various plant diseases. Root rot disease, in particular, causes substantial P. notoginseng yield reduction and economic losses. High-depth next-generation sequencing technology was used to analyze the rhizosphere and root endophyte microbial communities of P. notoginseng to compare the characteristics of these two communities between healthy and root rot diseased P. notoginseng plants, and to clarify the relationship between these microbial communities and root rot disease.Results: The P. notoginseng rhizosphere microbial community was more diverse than the root endophyte community, and the difference in functional pathways between healthy and diseased P. notoginseng plants was greater in the root endophyte than in the rhizosphere communities. Multi-database annotation results showed that the highest number of endophytic bacteria occurred in the roots of diseased plants. The number of carbohydrate-active enzymes database families was also higher in diseased roots. The RND antibiotic efflux function was higher in the healthy samples. A high abundance of Variovorax paradoxus and Pseudomonas fluorescens occurred in the healthy and diseased root endophyte communities, respectively. Ilyonectria mors-panacis and Pseudopyrenochaeta lycopersici were most abundant in the diseased samples. In addition, the complete genome of two unknown Flavobacteriaceae species and one unknown Bacteroides species were obtained based on binning analysis.Conclusions: The rhizosphere and root endophyte microbial communities of healthy and root rot diseased P. notoginseng showed marked differences in diversity and functional pathways. The higher mapping values obtained for the diseased samples reflected the occurrence of root rot disease at the molecular level. Variovorax paradoxus and Pseudomonas fluorescens may be antagonistic bacteria of root rot in P. notoginseng, whereas Ilyonectria mors-panacis and Pseudopyrenochaeta lycopersici appear to be P. notoginseng root rot pathogens. Our study provides a theoretical basis for understanding the occurrence of root rot in P. notoginseng and for further research on potential biological control agents.

Understanding Occurrence Regularity and Preventive Measure for Panax notoginseng Leaf Spot Disease in Forest Environments

“…Thus, achieving standardized and large-scale production of P. notoginseng in underforest locations [8]. The PPF alleviate the land pressure caused by the obstacles of continuous P. notoginseng cultivation, save production costs, better solve the difficult problems of heavy metals and excessive agricultural residues in traditional cultivation, and improve the quality of P. notoginseng from the source [9]. By 2020, the PPF had exceeded 1,333 hm 2 , serving as a strong technical strategy for the 2 high-quality production of the medicinal herbs cultivated in underforests based on the principle of habitat diversity for pest control [10].…”

“…The incidence rate ranges from 5% to 20%, with severity reaching as high as 60-70%. Research indicates a complex array of pathogens, including Ilyonectria, Plectosphaerella, Clonostachys, Gibberella, Fusarium, and Chalara, contributing to P. notoginseng root rot [8,9]. Root rot exacerbates challenges associated with continuous cropping in P. notoginseng, worsening with each planting cycle.…”