Genomic analysis of the marine fungi Rhodotorula sphaerocarpa ETNP2018 reveals adaptation to the open ocean

This is the authors' abstract. We don't add key points for this paper.

Background Despite a rising interest in the diversity and ecology of fungi in the ocean, there are few published genomes of fungi isolated from the ocean. The basidiomycetous yeast genus Rhodotorula are prevalent and abundant in the open ocean, and they have been isolated from a wide range of other environments. Many of these environments are nutrient poor, such as the Antarctica and the Atacama deserts, raising the question as to how Rhodotorula yeasts may have adapted their metabolic strategies to optimize survival under low nutrient conditions. In order to understand their adaptive strategies in the ocean, the genome of R. sphaerocarpa ETNP2018 was compared to that of fourteen representative Rhodotorula yeasts, isolated from a variety of environments. Results Rhodotorula sphaerocarpa ETNP2018, a strain isolated from the oligotrophic part of the eastern tropical North Pacific (ETNP) oxygen minimum zone (OMZ), hosts the smallest of the fifteen genomes yet encodes an average number of proteins and transcription factors. Its genome exhibits a distinct reduction in genes dedicated to Major Facilitator Superfamily transporters as well as biosynthetic enzymes. However, its core metabolic pathways are fully conserved. Our research indicates that the selective pressures of the ETNP OMZ favor a streamlined genome with reduced overall biosynthetic potential balanced by a stable set of core metabolisms and an expansion of mechanisms for nutrient acquisition. Conclusions In summary, this study offers novel insights into the adaptation of fungi to the oligotrophic ocean and provides valuable information for understanding the ecological roles of fungi in the ocean.