Antimicrobial activity of the extracts of Terfezia claveryi and Tirmania pinoyi against gram-positive and gram-negative bacteria causal agent of diseases in tomato

Tomato diseases caused by virus, bacteria and fungi have been reported worldwide and caused considerable economic losses. Among all diseases, attention is paid to those caused by bacteria. In this study, the extracts of two "desert truffles" Terfezia claveryi and Tirmania pinoyi were tested against six bacterial species, causal agent of economically important tomato diseases: Pseudomonas corrugata, P. mediterranea, P. syringae pv. tomato Pectobacterium carotovorum subsp. carotovorum, Xanthomonas vesicatoria and Clavibacter michiganensis subsp. michiganansis. The extracts from both fungal species, evaluated by agar well diffusion method, showed an antimicrobial activity against all the tested bacterial strains with inhibition zones ranging from 0.33 to 1.88 cm. For both extracts, minimum inhibition concentrations (MIC) determined by turbidimetric technique was 12.5 μg mL-1. No phytotoxic effect was observed on tomato leaves. These results showed that antimicrobial metabolites from desert truffles could represent novel natural products to be applied in modern agriculture aimed to produce high quality, safe and sustainable food products.