Background: Ginseng, an important traditional Chinese medicine and a new resource food, has two production modes: farmland ginseng and forestland ginseng. Ginseng faces many problems such as high soil bulk density, easy hardening, low nutrient content, reduced porosity and increased soil acidification because of continuous cropping. Increasing studies indicate that plant rhizosphere symbiotic bacteria have an important effect on plant growth and development. We speculate that differences in microbial community may play an important role in promoting ginseng growth, development and health. To reveal the differences between farmland and forestland ginseng cultivation, and to address problems associated with continuous ginseng cropping, we investigated the effects of differences in plant rhizosphere symbiotic bacterial communities in promoting ginseng growth, development, and health. Result: In the present study, the microbial communities in the rhizosphere of different genotypes and ecological environments were analyzed using the high-throughput sequencing platform Illumina, phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt), and other technologies. The organic matter, total nitrogen, available nitrogen, and available phosphorus contents in forestland soil were significantly different from those in farmland. The bacterial communities of ginseng in forestland, farmland, and greenhouse environments have specific dominant groups at the phylum and genus levels. There were differences in the gene functions of ginseng root-related bacterial communities between forestland and farmland. There were significant differences in the abundance distribution of rhizosphere bacteria among the different genotypes at the phylum and genus levels. Conclusions: There is a close relationship between the ecological environment and bacterial population structure, and the ecological environment of forestland is more conducive to the formation of rich rhizosphere bacterial populations; additionally, the genetic diversity is richer than that of farmland. The rhizosphere bacterial community structure of ginseng was influenced by genotype, and there was a correlation between the distance between ginseng genotypes and the stratified clustering of its rhizosphere bacterial community structure.

The ginseng industry’s reliance on chemicals for fertilizer and pesticides has adversely affected the environment and decreased the quality of ginseng; therefore, microbial inoculum is an effective way to restore the damaged soil in ginseng fields. To investigate the effects of plant growth-promoting rhizobacteria (PGPR) and spent mushroom substrate (SMS) on soil and plant quality in ginseng, high throughput sequencing was performed to examine the microbial community structures in ginseng rhizosphere soil. All treatments significantly increased soil nutrient, enzyme activity, and ginseng biomass compared to control (p < 0.05). The combination of PGPR and SMS notably enhanced soil enzyme activities: urease (7.29%), sucrase (29.76%), acid phosphatase (13.24%), and amylase (38.25%) (p < 0.05). All treatments had different effects on ginseng rhizosphere soil microbial diversity. Significantly, the combination treatments enhanced microbial diversity by increasing the abundance of beneficial bacteria such as Allorhizobium-Neorhizobium-Pararhizobium-Rhizobium and Plectosphaerella, meanwhile suppressing harmful Klebsiella. The relative abundance of Fusarium was reduced to some extent compared with the application of SMS alone. The soil organic matter, available potassium, available phosphorus, and alkaline nitrogen, as key factors, influenced microbial community structures. Overall, the combination of PGPR and SMS positively impacted the rhizosphere environment and ginseng plant quality.

Rusted root rot is one of the most common root diseases in Panax ginseng, and Cylindrocarpon destructans is one of the main pathogenic fungus. The objective of this study was to screen and explore the extracts of biocontrol bacteria isolated from ginseng rhizosphere soil against Cylindrocarpon destructans. Bacterial strains Bacillus amyloliquefaciens YY8 and Enterobacteriacea YY115 were isolated and found to exhibit in vitro antifungal activity against C. destructans. A combination of crude protein extract from B. amyloliquefaciens YY8 and ethyl acetate extract from Enterobacteriacea YY115 in a 6:4 ratio exhibited the strongest antifungal activity against C. destructans. Measurements of electrical conductivity, protein content, and nucleic acid content in suspension cultures of C. destructans treated with a mixture extracts indicated that the extracts disrupted the cell membranes of rusted root rot mycelia, resulting in the leakage of electrolytes, proteins, and nucleic acids from the cells, and ultimately inhibiting the growth of C. destructans. The combined extracts suppressed the infection of ginseng roots discs by C. destructans effectively. The extracts obtained from the two bacterial strains effectively inhibited C. destructans in P. ginseng. It can provide scientific basis for the development of new biological control pesticides, reduce the use of chemical pesticides, and promote the sustainable development of agriculture.

In this study, Illumina MiSeq sequencing of 16S and ITS2 rRNA genes were used to determine the dynamic changes in bacterial and fungal communities and soil properties and enzyme activities in rhizosphere soil of ginseng under forest after 5, 1...