Results and discussionOur analyses showed that the predicted secretomes of the analyzed species comprised between 7 and 8% of the respective proteomes. Mining of transcriptome data collected during previous studies showed that 18% of the genes encoding predicted secreted proteins were upregulated during the interactions with the mycohosts Fusarium graminearum and Helminthosporium solani. Functional annotation of the predicted secretomes revealed that the most represented protease family was subclass S8A (11–14% of the total), which include members that are shown to be involved in the response to nematodes and mycohosts. Conversely, the most numerous lipases and carbohydrate-active enzyme (CAZyme) groups appeared to be potentially involved in eliciting defense responses in the plants. For example, analysis of gene family evolution identified nine CAZyme orthogroups evolving for gene gains (p ≤ 0.05), predicted to be involved in hemicellulose degradation, potentially producing plant defense-inducing oligomers. Moreover, 8–10% of the secretomes was composed of cysteine-enriched proteins, including hydrophobins, important for root colonization. Effectors were more numerous, comprising 35–37% of the secretomes, where certain members belonged to seven orthogroups evolving for gene gains and were induced during the C. rosea response to F. graminearum or H. solani. Furthermore, the considered Clonostachys spp. possessed high numbers of proteins containing Common in Fungal Extracellular Membranes (CFEM) modules, known for their role in fungal virulence. Overall, this study improves our understanding of Clonostachys spp. adaptation to diverse ecological niches and establishes a basis for future investigation aiming at sustainable biocontrol of plant diseases.