Virocell resource manipulation under nutrient limitation

Virus-infected cells, called virocells, impact host metabolic functions, resources, and ecosystem processes, but the effects of nutrient limitation remain less well understood. Here, we leverage transcriptomic, proteomic, and endo- and exo-metabolomic data from two Pseudoalteromonas virocells independently infected by unrelated dsDNA viruses, PSA-HS2 (HS2-virocells) and PSA-HP1 (HP1-virocells), to examine how phosphate limitation affects virocell resource manipulation intra- and extracellularly. Intracellularly, we find that (i) HP1-virocells boost amino acid production toward the end of the infection cycle but deplete amino acid pools relative to HS2-virocells; (ii) both virocells dampen the production of de novo nucleotide synthesis proteins; (iii) HS2-virocells switch from de novo synthesis to recycling of phospholipids, whereas HP1-virocells decrease both activities; (iv) all cells (virocells and uninfected cells), but HP1-virocells especially, increase membrane fluidity; and (v) both virocells increase iron storage. Extracellularly, (i) polyphenols, a stress marker, increased in all cells, particularly in HP1-virocells, and (ii) only HP1-virocells showed elevated unsaturated hydrocarbons and oxygen-rich metabolites, which are likely byproducts of intracellular metabolic activity. These findings advance our understanding of how environmental conditions shape virocell activities in ecologically relevant nutrient-limited conditions and reveal distinct responses of virocells to infection by unrelated viruses.