Talaromyces pinophilus Strain HD25G2 as a Novel Biocontrol Agent of Fusarium culmorum, the Causal Agent of Root and Crown Rot of Soft Wheat

<i>Fusarium culmorum</i> is the causal agent of root rot and crown rot in soft wheat. The aim of this study was to investigate the control mechanism of <i>Talaromyces pinophilus</i> HD25G2 as a biocontrol agent against <i>F. culmorum</i>. This involved the isolation and molecular identification of <i>Fusarium</i> and <i>Talaromyces</i> strains from soft wheat. The assay included the inhibition test of <i>F. culmorum</i> mycelial growth on potato dextrose agar and soft wheat media at two water activity values (0.98 and 0.95), its production of mycotoxins, and the fungal cell wall-degrading enzymes implicated in the antagonistic effect of <i>T. pinophilus</i>. The results showed that <i>T. pinophilus</i> and its extract free of cells reduced the growth of <i>F. culmorum</i> by over 55%. Interestingly, the <i>T. pinophilus</i> HD25G2 showed high chitinase, protease, and cellulose production on solid media. In addition, chitinolytic and proteolytic activities were estimated at the values of 1.72 ± 0.02UI and 0.49 ± 0.01UI, respectively. However, the mycotoxin evaluation assay revealed that <i>F. culmorum</i> HD15C10 produced zearalenone (ZEA) and the biocontrol agent enhanced its production, but the early inoculation of <i>T. pinophilus</i>, before <i>F. culmorum</i> growth onset, inhibited 100% its growth and, therefore, prevented the presence of ZEA. Hence, this strain can be proposed as a biocontrol agent against <i>F. culmorum</i>, and it can be further investigated for biocontrol of <i>Fusarium</i> root and crown rot in vivo.