Comparison of rhizosphere microbial community of Panax notoginseng with root rot under natural forest and in the field

Abstract:

[Background] Rhizosphere microbial community is closely related to the root rot of Panax notoginseng (PN). However, PN with root rot under natural forest is rarely reported. [Objective] To compare rhizosphere microbial community of PN with root rot under natural forest and in the field and to lay a basis for the control of root rot and wild cultivation of PN. [Methods] Rhizosphere soil of PN with root rot under the natural forest and in the field was respectively collected, and species composition and diversity of soil bacterial and fungal communities were analyzed based on high-throughput sequencing. Moreover, we determined soil physicochemical properties and enzyme activity. [Results] The composition of bacterial and fungal communities in the rhizosphere soil was different between PN with root rot under natural forest and that in the field. The rhizosphere soil of PN under natural forest had abundant Basidiomycota, Acidobacteria, and Verrucomicrobia species, while that of PN in the field boasted abundant Ascomycota, Proteobacteria, and Chloroflexi species. At the genus level, Fusarium was dominant in the rhizosphere soil of PN under natural forest, with relative abundance of 17.30%, and Plectosphaerella dominated the rhizosphere soil of PN in the field, with relative abundance standing at 22.55%. The relative abundance of Candidatus Bacilloplasma in non-PN rhizosphere soil under natural forest was 8.05%, while the figure was quite low for rhizosphere soil of PN (0−1.25%). The organic matter content, enzyme activity, and microbial diversity in the rhizosphere soil of PN with root rot in the field were lower than those under natural forest (P<0.05). Redundancy analysis (RDA) suggested significant differentiation of soil bacterial and fungal communities in the rhizosphere soil of PN under natural forest and in the field, which was closely related to the soil organic matter content and enzyme activity. [Conclusion] The rhizosphere microbial composition of PN with root rot under natural forest was significantly different from that in the field. For the cultivation of PN in the field, efforts should be made to improve soil organic matter content, enzyme activity, and microbial diversity. In addition to pathogenic Fusarium, Plectosphaerella should be emphasized in the cultivation of PN.

Key words:Panax notoginseng;natural forest;root rot;rhizosphere microorganism;soil nutrients