The Growth-Promoting and Colonization of the Pine Endophytic for Pine Wilt Disease Control.

In this study, we focused on evaluating the impact of BHJ04 on the growth of seedlings and its biocontrol efficacy against pine wilt disease (PWD). Additionally, the colonization dynamics of BHJ04 on were examined. The growth promotion experiment showed that BHJ04 significantly promoted the growth of the branches and roots of . Pot control experiments indicated that strain BHJ04 significantly inhibited the spread of PWD. There were significant changes in the expression of several genes related to pine wood nematode defense in , including chitinase, nicotinamide synthetase, and triangular tetrapeptide-like superfamily protein isoform 9. Furthermore, our results revealed significant upregulation of genes associated with the water stress response (dehydration-responsive proteins), genetic material replication (DNA/RNA polymerase superfamily proteins), cell wall hydrolase, and detoxification (cytochrome P450 and cytochrome P450 monooxygenase superfamily genes) in the self-regulation of . Colonization experiments demonstrated that strain BHJ04 can colonize the roots, shoots, and leaves of , and the colonization amount on the leaves was the greatest, reaching 160,000 on the 15th day. However, colonization of the stems lasted longer, with the highest level of colonization observed after 45 d. This study provides a preliminary exploration of the growth-promoting and disease-preventing mechanisms of BHJ04 and its ability to colonize pines, thus providing a new biocontrol microbial resource for the biological control of plant diseases.