Molecular typing, biodiversity, and biological control of endophytic fungi of Triticum aestivum L. against phytopathogenic fungi of wheat

The current study aimed to evaluate the biodiversity and antagonistic potential of 22 endophytic fungal species belonging to 10 endophytic genera, namely Acremonium, Alternaria, Aspergillus, Fusarium, Gliocladium, Nigrospora, Penicillium, Pochonia, Scopulariopsis, and Stachybotrys, along with 2 morphospecies of mycelia, namely a yellow sterile septate mycelium (YSSM) and a dark sterile septate mycelium (DSSM), living within healthy Triticum aestivum L. against nine wheat pathogenic fungi identified as Alternaria alternata, Alternaria cichorii, Alternaria dianthi, Alternaria sonchi, Aspergillus petrakii, Curvularia penniseti, Fusarium oxysporum, Fusarium semitectum, and Fusarium solani obtained from naturally infected plants. The highest count and frequency in T. aestivum were recorded for Fusarium subglutinans (n = 81 and Rf = 34.91%) followed by DSSM (n = 32 and Rf = 13.79%). In vitro DSSM studies showed the highest antagonistic activity of 56.52% reduction against A. petrakii, while F. subglutinans inhibited F. semitectum by 72.97%. These two endophytic isolates were then selected as fungal bioagents to control root rot disease in wheat caused by A. petrakii and F. semitectum under greenhouse conditions. Wheat plants growing from seeds inoculated with DSSM were more resistant to root rot disease in soil infected with A. petrakii, and they showed reduced root rot severity percentage (15.56%) and disease index (0.27) compared to the values of 40% and 1.13, respectively, for these parameters in untreated plants. Furthermore, treatment of seeds with F. subglutinans before planting in soil infected with F. semitectum reduced the disease severity percentage and the disease index from 50% and 2.20 to 20% and 0.47, respectively. These endophytic fungi also markedly increased the growth parameters (length, fresh weight, and dry weight of shoots and roots) of wheat plants growing in soils infected with these phytopathogens. The present study showed that wheat is a promising ecological niche for different fungal endophytes that assist their host plants to survive and resist the harmful effects of phytopathogenic fungi, improve wheat growth, and develop fungal strains as biological control solutions against wheat diseases.