Mycoparasitic transcription factor 1 (BcMTF1) participates in the Botrytis cinerea response against Trichoderma atroviride

<i>Botrytis cinerea</i> is a phytopathogenic fungus. Traditional control using fungicides has faced challenges, prompting the exploration of sustainable alternatives such as biocontrol. <i>Trichoderma atroviride</i>, a promising biocontroller, is well-known for its mycoparasitism. However, the molecular processes involved in this fungal-fungal interaction, particularly regarding the defense mechanisms of the pathogen, have yet to be deeply studied. Here, we investigated the transcriptional defense responses of <i>B. cinerea</i> to <i>T. atroviride</i>. We focused on four <i>B. cinerea</i> transcription factors (TFs) differentially expressed during interaction with the biocontroller. Mutants lacking these TFs exhibit increased sensitivity to <i>T. atroviride</i>, with the Bcin07g06800 (BcMTF1) loss-of-function mutant being most susceptible. Genes predicted to be regulated by mycoparasitic transcription factor 1 were differentially expressed during this interaction. BcMTF1 influences <i>B. cinerea</i>'s resistance to mycoparasitism by regulating the expression of genes potentially involved in fungal defense against <i>Trichoderma</i>. The findings provide insights into the transcriptional processes underlying fungal-fungal interactions.