Microbial Community Structure and Diversity of Endophytic Bacteria and Fungi in the Healthy and Diseased Roots of <i>Angelica sinensis</i>, and Identification of Pathogens Causing Root Rot

Abstract

Angelica sinensis (Oliv.) Diels is an important traditional Chinese herbal medicine, and its main medicinal part is the root. In recent years, root rot has become one of the bottlenecks hindering the healthy and green development of Angelica cultivation due to the inappropriate application of chemical fertilizers, pesticides, plant growth regulators, and continuous cropping. In this study, high-throughput sequencing technology was adopted to reveal the differences in the community structure and diversity of endophytic bacteria and fungi in the roots of healthy and diseased A. sinensis. The results showed that the diversity index of endophytic bacterial communities was significantly higher in healthy root than in diseased Angelica root systems. There was a significant difference in endophytic fungal community diversity only at the m1 sampling site. There was a significant difference in the β-diversity of bacterial communities, but not of fungi. In terms of community composition, Proteobacteria was the dominant phylum of bacteria, and Sphingobium and Pseudomonas were the dominant genera; Ascomycota and Basidiomycota were the dominant phyla of fungi, and Plectosphaerella, Paraphoma, and Fusarium were the dominant genera. In addition, the relative abundance of the genera Sphingobium and Pseudomonas was higher in healthy roots, while Fusarium was higher in diseased samples. Among the five pathogens isolated from diseased root, four strains were Fusarium sp., and one was Paraphoma chrysanthemicola, which is reported for the first time. Our findings indicate that the endophyte community structure of A. sinensis infected with root rot changed significantly compared with healthy plants, and Fusarium is an important pathogenic factor, which provides a valuable microbiological basis for the targeted biocontrol of Angelica root rot.

Keywords

• <i>Angelica sinensis</i>
• endophytes
• microbial community structure
• diversity analysis
• root rot