The Study on Microbial Diversity of Rhizosphere in Continuous Cropping System of Panax notoginseng

Purposes This research aimed at the problem of soil-borne root rot in Panax notoginseng replant failure protrude increasingly, to explore correlation among microbial diversity, community composition and metabolic activity with root rot.

Methods The metabolic functional diversity analysis was used to study the rhizosphere soils that originated from continuous cropping for 3 years and 4 years healthy plants and root rot plants. Microorganisms in soils and roots were isolated and cultured by various medium, PCR based on the consensus primers of 16S rDNA sequences and ITS regions, Blast homology comparison and phylogenetic tree analysis.

Results The Shannon and McIntcosh of microbial community had a significant difference between healthy plant group and root rot group (P<0.05), and the physiological activity of soil microbial communities of healthy plants were higher than that of rot plants. There were 172 strains isolated in the rhizosphere soil,Bacillus, Pseudomonas, Arthrobacter as the dominant microflora in healthy plants soils, and Flavobacterium, Mucor and Fusarium as the dominant microflora in rot plant soils. There were 121 strains isolated in roots, Bacillus and Pseudomonas as the dominant microflora in healthy roots, and Fusarium, Rahnella and Erwinia as the dominant microflora in rot root.

Conclusions Soil-borne disease in P. notoginseng replant failure is closely related to the community structure and metabolic functional diversity. From the perspective of micro ecology, this study provides a scientific theoretical basis for improving the soil health status and controling P. notoginseng root rot.