In silico structural and functional characterization of the Yap1 transcription factor in fungi of the Tuber genus: a study approach on the mechanisms of response to oxidative stress

Tuber genus includes hypogeous ectomycorrhizal (ECM) fungi, widely recognized as truffles. Truffles spend much of their life in a vegetative form in the soil, a crucial phase to ensure the growth and the accomplishment of their life cycle. Adverse events to which they may be subjected, i.e., rise in temperature, drought, and biotic stress factors, can influence the levels of oxidative stress, increasing the production of free radicals. It is known that both prokaryotes and eukaryotes have evolved various primary antioxidant defenses to protect themselves from oxidative damage. In some eukaryotes, transcription factors are activated to regulate the genes responsible for producing enzymes and proteins necessary to reduce ROS levels. In yeasts the Yap1 protein is a key modulator of oxidative stress response. In this study, we used an in silico approach to characterize the Yap1 transcription factor in fungi of the Tuber genus, using Saccharomyces cerevisiae as the main reference model. The phylogenetic analysis based on the Yap1 protein sequences from 24 fungal species showed clustering consistent with their taxonomic relationships, including those observed within Tuber genus. The amino acid alignment revealed the conservation within the Tuber species of cysteine-rich domains (nCRD and cCRD) and motifs potentially involved in redox regulation. Finally, by silico investigation of Yap1 possible protein interactions and three-dimensional structure in Tuber melanosporum, it was possible to provide further elements to understand the molecular mechanisms underlying the functionality of Yap1 and the response mechanism to oxidative stress modulated by it in fungi of the Tuber genus. The evidence obtained represents an essential starting point for understanding a complex process that can strongly influence the biological cycle of the truffle and compromise its fruiting.