Effect of Trunk Injection of Emamectin Benzoate on Diversity of Endophytic Bacteria and Fungi in Pinus massoniana

On April 20th, 2022, sample plot with 0.33ha of coniferous and broad-leaved mixed forest was selected, and 20 Pinus massonina trees with 20-35-year age were selected for trunk injection of 2.3% micro-emulsion of emamectin benzoate. On September 20th, 2022, bits of 3 injected trees and 3 controls (non-injection) were sampled from trunk and branch. Community structure and diversity of endophytic bacteria (16S rRNA V3+V4) and fungi (ITS) was carried out by high-throughput sequencing technology Illumina NovaSeq 6 000. A total of 1,169 bacterial and 7 250 fungal operational taxonomic units (OTUs) were obtained, with 27 phyla and 340 genera of bacteria, 15 phyla and 594 genera of fungi. The number of OTUs in the injected trees reduced by 71.84% compared with that in the control. The differences in the community structure of endophytic bacteria at the phylum and genus levels were not obvious. The highest relative abundance of bacteria at phyla was Cyanobacteria and Proteobacteria and that of