Nematicidal Activities of Bacterial Volatiles fromPseudoduganella violaceinigra G5-3 and Novosphingobium pokkalii G8-2 against the Pine Wood Nematode Bursaphelenchus xylophilus

Abstract

Naturally-occurring volatile compounds with nematicidal activities have significant economic importance in agriculture and forestry. We identified two Gram-negative bacteria Pseudoduganella violaceinigra G5-3 and Novosphingobium pokkalii G8-2 that produced volatile compounds with potent nematicidal activities. Mortalities for the supernatants of P. violaceinigra G5-3 and N. pokkalii G8-2 to Bursaphelenchus xylophilus were 98.26% and 93.10% in 24 h, respectively. Volatiles of the two strains were analyzed by solid-phase microextraction coupled with gas chromatography/mass spectrometry. The compounds 2,5-dimethyl pyrazine, 4-dimethylaminopyridine, benzyl acetate, phenethyl butyrate, phenylethyl alcohol and acetophenone possessed nematicidal activity against B. xylophilus with LC90 values of 33.72, 1.83, 0.92, 0.20, 13.22 and 10.11 mM as assayed using the pure commercial compounds, respectively. This study provides a theoretical basis for the utilization of microorganisms to generate compounds with nematicidal activity.