Efficacy of six essential oils for the management of Meloidogyne incognita in eggplant and their effect on the expression of plant defense genes

Abstract

Hydrodistilled essential oils from six Egyptian plants were analyzed by gas chromatography/mass spectrometry (GC/MS). The essential oils were tested for their nematicidal activity against Meloidogyne incognita as well as their effect on the expression of defense genes of eggplant. Artemisia judaica oil (LC₅₀ = 37.15 mg/L) had the highest toxicity against second-stage juveniles (J2), followed by Origanum vulgare and Callistemon viminalis oils. Likewise, A. judaica essential oil (IC₅₀ = 15.68 mg/L) caused the greatest reduction in egg hatching and it was three times more active than oxamyl. In greenhouse experiment, the essential oils of A. judaica, O. vulgare and C. viminalis reduced gall and egg numbers per eggplant, and J2 numbers in soil at 500 and 1000 mg/L. Moreover, the essential oils improved the growth of eggplant and increased the expression of eggplant defense genes, chitinase, thaumatin-like proteins, and polyphenol oxidase, compared with control. The information obtained from this study suggests that the essential oils of A. judaica, O. vulgare and C. viminalis have a potential to be used for the management of M. incognita.

Keywords:

• Essential oils
• chemical composition
• nematicidal activity
• eggplant
• Meloidogyne incognita
• plant gene expression

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was partially supported by the Alexandria University Research Fund (ALEX-REP).