西洋参根腐病发生与根际真菌群落变化关系研究

Research on relationship between occurrence of root rot and changes of fungal communities in rhizosphere of Panax quinquefolius

根腐病是西洋参栽培过程中常见的一种病害,分析根际土壤真菌群落与西洋参根腐病间关系,可为解决根腐病问题提供一定线索。该研究利用Illumina Mi Seq测序技术,分析了空白地（C组）、健康参根际土壤（N组）和根腐病参根际土壤（R组）样品中真菌群落结构多样性及组成变化。通过测序,共获得高质量序列505 968条,样品稀释曲线表明测序深度充足,取样合理。真菌群落主要属于Ascomycota（54.9%）,Basidiomycota（5.6%）等9个门,其优势菌门为Ascomycota;Monographella（9.3%）,Archaeorhizomyces（3.9%）,Mortierella（2.9%）等115个属,其优势菌属为Monographella。在属水平上,与C和N组相比,R组中Monographella和Mortierella丰度均显著增加。α多样性指数表明,与C组相比,N和R组中真菌群落多样性指数降低,真菌种类减少,R组达到最小。β多样性指数表明,各样品中真菌群落结构均存在明显差异。聚类热图显示各样品中菌属差异较大,R组中Monographella和Mortierella比例显著高于C和N组,Trichoderma,Penicillium,Cadophora在R组中所占比例较小;Phoma和Gibberella在R组中较N组中所占比例显著增加。该研究通过分析土壤根际真菌多样性及群落构成变化,表明真菌多样性指数显著降低和群落结构失衡可能导致西洋参根腐病的发生,这为防治西洋参根腐病发生提供了一定的理论依据。

The root rot disease is a common disease during the cultivation of Panax quinquefolius. In order to provide some clues for solving the root rot disease of P. quinquefolius,the relationship between rhizosphere soil fungal communities and root rot of P. quinquefolius was investigated in this study. The diversities and the changes of fungal communities structure in blank control group（ group C）,rhizosphere soil of healthy P. quinquefolius（ group N） and occurrence of root rot in rhizosphere soil of P. quinquefolius（ group R） were analyzed byusing the Illumina Mi Seq high-throughput sequencing technology. A total of 505 968 high-quality sequences were obtained through high-throughput sequencing and the rare faction curves analysis showed that the sequencing depth was sufficient and the sampling was reasonable. The fungal communities structure of rhizosphere soil samples mainly belonged to 9 phylums including Ascomycota（ 54. 9%）,Basidiomycota（ 5. 6%）,etc.,and the dominant specie was Ascomycota of the total fungal identified,respectively. The115 genera of fungi were tested,including Monographella（ 3. 9%）,Archaeorhizomyces（ 3. 9%）,Mortierella,etc.,and the dominant specie was Monographella. At the genus level,the abundance of Monographella and Mortierella in group R increased significantly compared with the abundance in groups C and N. Alpha diversity index of species showed that the diversity index of fungal communities reduced and the numbers of fungi reduced in group N and R,compared with group C,and reaching the minimum in group R. Beta diversity index of species showed that there was a significant difference in the fungal communities structure in each sample. In addition,the heat map analysis revealed that the dominant fungal genera were significantly different among the each sample. The proportion of Monographella and Mortierella in group R was significantly higher than that in group C and N,while the proportion of Trichoderma,Penicillium and Cadophora in group R was extremely low. The proportion of Phoma and Gibberella in group R increased significantly compared with group C. This study clarified the decline of diversity index and the imbalance of community structure in fungi may lead to the occurrence of root rot in P. quinquefolius by analysis of fungal diversity and community composition in the rhizosphere soil of P. quinquefolius in this study,which provided a theoretical basis for the prevention and treatment of occurrence of root rot in P. quinquefolius.