Effect of Bursaphelenchus xylophilus infection on the endophytic bacterial community structure in different parts of Pinus massoniana seedlings

Abstract

Objective With an investigation of the structural changes of the endophytic bacterialflora of pine stems, pine needles and pine roots, this study is aimed to fully explore the endophytic bacterial resources of Pinus massoniana. Method DGGE and high-throughput sequencing technology was employed in the exploration of the structural changes of endophyticbacterial flora of three-year-old P. massoniana trees upon the infection of Bursaphelenchus xylophilus disease. Result (1) There was a significant diversity in the endophytic bacterial community structure in different parts of P. massoniana trees with the diversity decreasing from the pine stem to pine needles and to the root system. (2) There was significant increase in parts of the bacterial genera in pine stems after 15 days of infection, whereas there were no symptoms shown on the surface of the seedlings. (3) Of the 442 genera of endophytic bacteria detected in P. massoniana that fall into 35 phyla, 49 classes, 110 order and 210 families, the relative abundance of Methylobacterium, Sphingomonas, Hymenobacter, Pantoea, Sphingomonas and Curtobacterium in pine stems and pine needles varies greatly throughout the infection process. Conclusion The effect of the infection of B. xylophilus disease on the structure of the endophytic bacterial flora varies from none to pretty significant to extremely significant in roots, pine needles and pine stems respectively. And some endophytic bacteria may have potential biocontrol effects on B. xylophilus disease, which is conducive to the excavation of later biocontrol strains. In addition, real-time monitoring of changes in the bacterial community structure of pine stems during the peak period of infection is helpful to the early diagnosis of B. xylophilus disease. [Ch, 5 fig. 1 tab. 25 ref.]