Trichoderma species are known as excellent biocontrol agents against soil-borne pathogens that cause considerable crop losses. Eight strains of Trichoderma were isolated from five Egyptian regions. They identified based on translation elongation factor-1α (TEF1) sequencing as four different Trichoderma species: Trichoderma asperellum, Trichoderma harzianum, Trichoderma viride, and Trichoderma longibrachiatum. Optimal growth conditions (temperature and media), and the phosphate solubilization capability of Trichoderma strains were evaluated in vitro. Further, the ability of these strains to antagonize Fusarium solani, Macrophomina phaseolina, and Fusarium graminearum was also evaluated. The results revealed that Trichoderma harzianum (Th6) exhibited the highest antagonistic ability against F. solani, M. phaseolina and F. graminearum with inhibition rates of 71.42%, 72.97%, and 84.61%, respectively. Trichoderma viride (Tv8) exhibited the lowest antagonism against the same pathogens with inhibition rates of 50%, 64% and 69.23%, respectively. Simple-sequence repeats (SSRs) and random amplified polymorphic DNA (RAPD) markers were used to evaluate the genetic variability of the Trichoderma strains. The results revealed that of 45 RAPD amplified bands, 36 bands (80%) were polymorphic and of SSRs amplified 36 bands, 31 bands (86.11%) were polymorphic. The amplification of calmodulin and β-1,3-endoglucanase was noted at 500 bp and 230 bp, respectively. Data indicated that T. viride (Tv8) had the highest phosphate solubilization index (10.0 mm), while T. harzianum (Th6) had the lowest phosphate solubilization index (4.0 mm). In conclusion, T. harzianum (Th6) had the highest antagonistic activity in dual culture assay along with the growth rate; while T. viride (Tv8) had the highest phosphate solubilization activity. There are still gaps in obtaining new formulations, selecting potent Trichoderma strains to confirm disease control in planta. For improving Trichoderma recommendation in the organic agricultural system and sustaining the fertility of the soil, the field application of highly antagonistic biocontrol agents in different types of soil and plant species will be the first approach toward bio-pesticide treatments along with bio-fertilizer inoculation. Furthermore, secondary metabolites will be investigated for the most promising strains with the combination of different pathogens and application timing.

The present study aimed to isolate a Trichoderma species with dual action as a plant growth promoter in conjunction with antagonistic activity against the plant pathogen Colletotrichum lagenarium. Using internal transcribed spacer (ITS) sequences and inter simple sequence repeat markers (ISSR), eight strains of Trichoderma were identified, and their diversity was studied. In addition, some plant growth promoters such as indole acetic acid (IAA) and element solubilization were evaluated. Moreover, the activity of amylase, pectinase, cellulase, and chitinase was studied in the isolated species. Results showed that Trichoderma viride (T27) and Trichoderma atrobrunneum (T40) produced the highest IAA (80.36, 61.39 µg/mL), respectively and K solubilization efficiency (KE) (12.2 and 14.4, respectively). In contrast, Trichoderma afroharzianum (T31) and Trichoderma atrobrunneum (T40) had the highest zinc (Zn) solubilizer (7.1 and 7.2 cm), respectively. Strains T. viride (T27) and T. atrobrunneum (T41) showed the highest antagonistic activity against anthracnose fungi; therefore, they were examined under scanning electron microscopy. The SDS-PAGE protein pattern and its antigenicity analysis ranged between 40 and 180 kDa. The results of SDS-PAGE indicated that with chitin, both T27 and T40 presented different bands in their protein profile compared to the control (without chitin). The results suggest that T. viride (T27) and T. atrobrunneum (T40) could be used as eco-friendly bio-fungicides with a high potential plant growth promoter production.