Nematicidal endophytic bacteria obtained from plants

Abstract

Two hundred and six bacterial isolates were obtained from leaf, flower and stem of three healthy plants, Euphorbia pulcherrima Willd, Pyrethrum cinerariifolium Trev. and Heracleum candicans Wall. The nematicidal activity experiment showed that a total of 92 isolates displayed activity against Caenorhabditis elegans (Maupas) Dougherty, and 70 isolates resulted active against Bursaphelenchus xylophilus (Steiner & Buhrer) Nickle. Strain LCB-3 exhibited the strongest nematicidal activity against both two nematodes. According to the 16S rDNA, the strain LCB-3 was identified as Brevundimonas diminuta. Based on bioassay-guided fractionation, a nematicidal metabolite (R)-(-)-2-ethylhexan-1-ol was obtained from LCB-3. The median lethal concentrations (LC50) of the compound were 542.0 mg I-1 against C. elegans and 168.1 mg I-1 against B. xylophilus 48 h after treatment.