Morphological and molecular identification of Iraqi desert truffles and evaluation of their extracts for antibacterial activity against pathogens associated with oyster mushroom (Pleurotus spp.)

Abdullah Abdulkareem Hassan, Maha Talib Ibrahim, Waleed Khalid Ahmed

Abstract


Desert truffles (Terfezia spp.) are valuable hypogeous fungi recognized for their nutritional, medicinal, and antimicrobial properties; however, their potential application in managing bacterial diseases of edible mushrooms remains poorly explored. This study characterized two desert truffle species, T. nivea and T. claveryi, through morphological, microscopic, and molecular approaches and evaluated their antibacterial potential against oyster mushroom pathogens. Morphological and microscopic observations confirmed the identity of both species, with T. nivea characterized by whitish fruiting bodies, clavate asci, and ellipsoid ascospores, whereas T. claveryi exhibited brownish peridia, ovoid asci, and globose ascospores. ITS-rDNA amplification produced approximately 650 bp fragments, and sequence analysis confirmed species identity with 99.39% and 99.65% similarity to reference isolates of T. nivea and T. claveryi, respectively. Ethanolic and aqueous extracts of both truffles exhibited antibacterial activity against Pseudomonas pleuroti, P. agarici, P. reactans, and P. tolaasii, with ethanolic extracts generally showing higher inhibitory effects. GC–MS profiling revealed 17 and 9 bioactive compounds in T. claveryi and T. nivea, respectively, including antimicrobial metabolites such as 9-octadecenamide and ethyl 9,12-octadecadienoate. Application of T. claveryi aqueous extract significantly reduced brown blotch disease severity caused by P. agarici and enhanced biological efficiency and protein content of oyster mushrooms. The highest biological efficiency (122.78%) and protein content (27.47%) were recorded in Pleurotus floridanus treated with the truffle extract. The findings demonstrate that T. claveryi possesses promising antimicrobial and growth-promoting potential and could serve as a natural bioactive resource for sustainable management of bacterial diseases in oyster mushroom cultivation.


Keywords


Desert truffles, Terfezia spp., ITS-rDNA identification, Bioactive compounds, Antibacterial activity, Oyster mushroom pathogens, Pleurotus spp.

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References


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DOI: https://doi.org/10.33804/pp.010.04.6142

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