自然林下与田间根腐三七根际微生物群落特征及比较分析

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

摘要:

【背景】三七根际微生物群落特征与其土传根腐病害密切相关，而针对自然林下根腐三七的相关研究鲜见报道。【目的】比较分析自然林下与田间根腐三七根际土壤微生物群落的组成特征，结合土壤理化性质与酶活性分析，为三七根腐病害防治与仿野生栽培提供科学依据。【方法】采集自然林下与田间根腐三七根际土壤，利用高通量测序技术，分析土壤细菌与真菌群落的物种组成与多样性，并测定土壤理化性质和酶活性。【结果】自然林下与田间根腐三七根际土壤中细菌和真菌群落组成具有明显差异，自然林下根腐三七根际土壤中担子菌门(Basidiomycota)、酸杆菌门(Acidobacteria)和疣微菌门(Verrucomicrobia)的相对丰度较高，而田间根腐三七根际土壤中子囊菌门(Ascomycota)、变形菌门(Proteobacteria)和绿弯菌门(Chloroflexi)的相对丰度较高。在属分类水平，镰刀菌属(Fusarium)是自然林下根腐三七根际土壤中的优势菌群，相对丰度为17.30%，而癣囊腔菌属(Plectosphaerella)是田间根腐三七根际土壤中的优势菌群，相对丰度为22.55%；Candidatus Bacilloplasma在自然林下非三七根际土壤中的相对丰度达8.05%，而在三七根际土壤中的相对丰度大幅降低(0-1.25%)。与自然林下三七根际土壤相比较，田间根腐三七根际土壤有机质含量、酶活性与微生物多样性均显著降低(P<0.05)。冗余分析(redundancy analysis, RDA)表明，自然林下与田间根腐三七根际土壤细菌和真菌群落存在明显分化，与土壤有机质含量和酶活性密切相关。【结论】自然林下与田间根腐三七根际微生物群落组成存在明显差异；针对田间种植三七需要采取有效措施提高土壤有机质含量、酶活性与微生物多样性，除镰刀菌属外，还需特别关注癣囊腔菌属真菌对三七的侵害。

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.