ABSTRACTFungi compete against each other for environmental resources. These interspecific combative interactions encompass a wide range of mechanisms. In this study, we highlight the ability of the white-rot fungusPycnoporus coccineusto quickly overgrow or replace a wide range of competitor fungi, including the gray-mold fungusBotrytis cinereaand the brown-rot fungusConiophora puteana. To gain a better understanding of the mechanisms deployed byP. coccineusto compete against other fungi and to assess whether common pathways are used to interact with different competitors, differential gene expression inP. coccineusduring cocultivation was assessed by transcriptome sequencing and confirmed by quantitative reverse transcription-PCR analysis of a set of 15 representative genes. Compared with the pure culture, 1,343 transcripts were differentially expressed in the interaction withC. puteanaand 4,253 were differentially expressed in the interaction withB. cinerea, but only 197 transcripts were overexpressed in both interactions. Overall, the results suggest that a broad array of functions is necessary forP. coccineusto replace its competitors and that different responses are elicited by the two competitors, although a portion of the mechanism is common to both. However, the functions elicited by the expression of specific transcripts appear to converge toward a limited set of roles, including detoxification of secondary metabolites.