Effect of salinity levels on antifungal activity of essential oil from Thymus against Fusarium oxysporum

Abstract

Thyme (Thymus sp.), a medicinal plant of the family Lamiaceae, is used in traditional medicine, contains a wide array of medicinally active components, in their great majority of a rather complex mixture of thymol, ρ-Cymene, γ-Terpinene, β-Caryophyllen, etc. This study aimed to evaluate the efficacy of Thymus vulgaris extract against Fusarium oxysporum f. sp.radicis-lycopersici strain under saline conditions, assuming soil with high salt content of the arid regions. Essential oil was extracted by hydrodistillation technique using a Clevenger apparatus. The essential oil compounds were identified by GC-MS analysis. Antifungal activity of essential oil against Fusarium oxysporum f. sp. radicis-lycopersici was investigated by agar dilution method. The main constituents of thyme essential oil were thymol (76.96 %), ρ-cymene (9.89 %) and γ-Terpinene (1.92 %). Essential oil from Thymus resented high in vitro activity, in controlling conidial germination and mycelial growth. However, the oil was significantly not active against the spore production under a salinity medium. The results showed that mycelial growth was stimulated in concentrations with 0.6 -1.5 %. In contrast, it was significantly reduced at a higher concentration (2 %). The application of NaCl caused a significant increase in the conidia production at various concentrations tested. NaCl has a minor inhibitory effect on conidial germination only when the concentration was 2 %. The results of this study indicate that salinity decreases the efficacy of essential oil against the pathogen.

Impact of Various Salinity Levels and Fusarium oxysporum as Stress Factors on the Morpho-Physiological and Yield Attributes of Onion

“…The present findings showed 45-80% enhancement in FOC biomass at 2-4 dS m −1 and 32-37% enhancement at 5-8 dS m −1 compared to the control. Boumaaza et al [31] indicated similar results in a way, as various levels of salinity (NaCl) enhanced the production of conidia in Fusarium oxysporum and exhibited a slight impact, at higher concentrations, on the germination of conidia. Tawfik et al [32] revealed that sodium salts at higher concentrations inhibit the growth of Fusarium semitectum.…”