Effect of the hexanic extracts obtained from individual and co-culture of Trichoderma sp. and Bacillus subtilis on the growth of Colletotrichum acutatum in vitro

Abstract

The resistance of phytopathogenic fungi to chemical compounds has triggered the search for alternatives to their treatment. In this study, the antagonistic potential of hexanic extracts (EH) obtained from the individual cultures and co-cultures (CC) of Bacillus subtilis and Trichoderma sp (T. asperellum T1 (CC1), T3 (CC3), or Trichoderma sp. T2 (CC2)) against Colletotrichum acutatum was assessed. Exposure to EH obtained from individual cultures altered mycelial morphology and inhibited the radial growth of C. acutatum (15%-17%). In contrast, the HE obtained from CC at 300 μg/mL and 450 μg/mL inhibited the radial growth of C. acutatum by 10% and 15%, respectively. Additionally, the EH altered germ tube morphology and reduced conidia germination (66.53%). Finally, the combination of EH obtained from T. asperellum T1 at 750 μg/mL and the CC3 at 450 μg/mL increased the radial growth inhibition by 35%. The mixtures altered the polarized hyphal growth, suggesting that the structural integrity of the phytopathogen was affected. These results underscore that the interaction among biological control agents in vitro promotes the production of promising molecules analysis is a promising source of molecules with antagonistic effects against C. acutatum.