International Journal of Innovative Horticulture

The volatile organic compounds (VOCs) emitted by Trichoderma harzianum OTPB3 were extracted by head-space solid phase micro extraction and analyzed by gas chromatography mass spectrometry. About 94 compounds were detected, which includes 16 aliphatic hydrocarbons, 20 aromatic hydrocarbons, one monoterpinoid, 25 sesquiterpenoids, 13 alcohols, 10 each of aldehydes and ketones, one acid, one esters, three nitrogen and sulphur and four oxides compounds. The effect of VOCs on growth of Phytophthora infestans PIT30 and tomato were assessed. Among them, β-caryophyllene, 1,8 cineole, p-cymene and 1-octen-3-ol exhibited 100% inhibition of pathogen. â-caryophyllene significantly increased the seedling vigour index and seedling weight of tomato in comparison with control. The defence related genes showed significant increase in their expression in β-caryophyllene treated tomato seedlings. PR-6 gene, a basic proteinase inhibitor and a jasmonic acid (JA)/ethylene (ET) responsive marker gene showed highest expression of 6.36 folds in β-caryophyllene treated seedlings. PR-1, PR-5 and PR-3 also showed an upregulation of 2.2 to 2.5 folds. Therefore, this study identified that â-caryophyllene is capable of inhibiting P. infestans in vitro and promoting growth and eliciting ISR in tomato that may be employed in devising strategies to manage late blight disease of tomato under open field conditions.