[Differences of bacterial and fungal communities in the tree and rhizosphere of the healthy and twig blight-diseased bayberry].

Twig blight is a serious disease of bayberry, which limits bayberry production. In order to prevent and manage the disease, we used high-throughput sequencing technology to analyze bacterial and fungal community richness and diversity in various organs of the tree, bulk and rhizosphere soil of healthy and diseased bayberry. The results showed significant differences in richness and diversity of bacteria and fungi in bulk soil, rhizosphere soil, roots, trunks, barks, and leaves between twig blight diseased trees and healthy trees. In bulk soil, the richness and diversity of bacteria significantly decreased, while that of fungi significantly increased. In barks of diseased trees, the richness and diversity of bacteria significantly increased, and those of fungi significantly decreased. The relative abundance of dominant bacteria and fungi in various organs, bulk soil, and root surface soil changed significantly at phylum, class, and genus levels in the diseased trees. The relative abundance of Pseudomonas sp. on the trunks, roots, and root surface soils of diseased trees significantly decreased, and Fusarium sp. of the diseased root surface and bulk soils also significantly decreased, while the relative abundance of Penicillium sp. on the diseased root surface and bulk soils significantly increased. Pestalotiopsis sp., from the same genus as the twig blight pathogen, was less abundant in the roots but more abundant in the leaves, trunks, barks as well as root surface soils and bulk soils of the diseased bayberry trees than those of the health trees. The relative abundance of Pestalotiopsis sp. was positively correlated with those of most of the fungi. Our results might provide useful theoretical basis for the development of ecological improvement and healthy-tree cultivation technology, and biological control of bayberry twig blight disease.凋萎病是制约杨梅产业发展的严重病害。为了有效防控凋萎病,本研究分析了杨梅健康和感染凋萎病树体各部位及根表土和根围土中细菌和真菌群落的丰富度与多样性的差异。结果表明: 与健康树相比,病树根围土、根表土、根、枝干、枝皮和叶片的细菌和真菌丰富度均发生了显著变化,其中,根表土细菌和枝皮内真菌的丰富度和多样性均显著降低,而枝皮内细菌和根表土的真菌丰富度和多样性均显著升高。病树各部位及根表、根围土细菌和真菌的优势菌相对丰度在门、纲和属水平上发生了明显的变化,在病树枝干、根和根表土中的假单胞菌属及根表土、根围土中的镰刀菌属的相对丰度明显降低,病树根表土及根围土中青霉菌属的相对丰度明显增加。与凋萎病菌同属的拟盘多毛孢菌在病树根内显著减少,而在其他位置均大量增殖,其相对丰度与多数相对丰度较高的真菌呈正相关。本研究结果将为开发杨梅凋萎病的生态改良、培育健康树体和生物防治技术提供有效的理论依据。.