Molecular Characterization and Functional Analysis of Three Autophagy Genes, , , and , in .

The pine wood nematode (PWN), , is the pathogen responsible for pine wilt disease (PWD), a devastating forest disease with a pathogenic mechanism that remains unclear. Autophagy plays a crucial role in physiological and pathological processes in eukaryotes, but its regulatory mechanism and significance in PWN are unknown. Therefore, we cloned and characterized three autophagy genes, , , and in PWN. and were efficiently silenced through RNA interference, and we found that positively regulated the expression of . Silencing and severely inhibited feeding and reproduction in PWN, indicating that autophagy is essential for these processes. We then examined the expression patterns of these three autophagy genes in PWN under the stresses of α-pinene and HO, the main defense substances of pine trees, and during the development of PWD using quantitative reverse transcription polymerase chain reaction. The expression levels of , , and all significantly increased after nematodes were stressed with α-pinene and HO and inoculated into pine trees, suggesting that autophagy plays an important role in the defense and pathogenesis of PWN. In this study, the molecular characteristics and functions of the autophagy genes , , and in PWN were elucidated.