Isolation, Morphological and Molecular Identification of the Pathogenic and Competitors Fungi Associated with the Edible Mushroom Pleurotus sp. and Control Them

Abstract

Eleven fungal isolates were isolated from oyster mushroom culture media. 10 isolates showed antagonistic activity against P. pulmonarius, while two fungal isolates did not show any antagonistic activity. the highest pathogenic fungi were identified as T. longibrachiatum, T. pleuroticola, R. arrhizus, M. hiemalis and P. glabrum according to the morphological and molecular methods and were registered in the World Genetic Bank at NCBI with the accession numbers OM438162.1, OM438163.1, OM438161.1, OM453951.1 and OM438160.1, respectively, the species T. pleuroticola, R. arrhizus and M. hiemalis were recorded for the first time in Iraq at the molecular level. The effect of some oils on the growth of the oyster mushroom P. pulmonarius and its pathogenic fungi was studied, the results showed that the highest effect of jojoba oil, olive oil, almond oil, sesame oil and coconut oil at 5% was recorded the highest inhibition of the all tested pathogenic fungi, while no inhibitory effect was recorded for the oyster mushroom P. pulmonarius. Sodium bicarbonate at 3 and 5% showed complete inhibition of the growth of all pathogenic fungi. The results showed that 5% of acetic acid inhibits the pathogenic fungi T. longibrachiatum, R. arrhizus and T. pleuroticola, where the diameters of the colonies reached 2.5, 2.7 and 3.1 cm. respectively. The highest biological efficiency was recorded in P. eryngii growing in the medium treated with the pathogenic fungus P. glabrum in presence of sodium bicarbonate, which reached to 69.58%. In the interaction between oyster mushroom species and the media, the results showed that the highest infection rate was in P. eryngii in the medium treated with T. longibrachiatum, which reached to 39.56%, while the lowest infection rate was with P. pulmonarius grown in the medium treated with sodium bicarbonate and the pathogenic fungus P. glabrum, which was 13.15%. Under the pathogens infection, the highest protein content was found in P. eryngii grown in the treated medium with sodium bicarbonate and P. glabrum resulting in 31.22%, while the lowest protein was12.07%. in P. ostreatus grown in the medium infected with T. longibrachiatum.