Alternaria alternata sequencing

Fungal secondary metabolites (SMs) are considered to be produced as a bioactive compounds resources in community environments, with variations in secondary metabolite profiles observed across different habitats. However, the defense mechanisms and SM regulation in fungal-fungal interactions, particularly in extreme environmental fungi, remain incompletely understood. Here, co-cultivation of the marine fungus Alternaria alternata with the terrestrial A. alternata and N. sphaerica species led to distinct changes in SM production. Transcriptomic and metabolomic analyses revealed the activation of several biosynthetic gene clusters (BGCs) in marine A. alternata, resulting in increased production of the bioactive compound alternariol (AOH), which inhibits the growth of competing fungi. Moreover, reactive oxygen species (ROS) appeared to serve as key signaling molecules in fungal interactions. As the ROS signal increases, the expression of oxidative stress genes is upregulated intracellularly, stimulating the defense response of A. alternata, ultimately leading to the synthesis of compound AOH, which inhibits the growth of N. sphaerica. This study provides important insights into fungal interactions in extreme environments and holds promise for the discovery and development of natural products through innovative approaches.