Phosphate limitation intensifies negative effects of ocean acidification on globally important nitrogen fixing cyanobacterium

The filamentous diazotrophic cyanobacteria Trichodesmium spp. supply fixed nitrogen (N) to the N-depleted oligotrophic oceans where their growth is often limited by the low availability of phosphorus(P) and/or iron. Previous studies have mostly been focused on the effects of ocean acidification on Trichodesmium under nutrient sufficient or iron-limited conditions. Only a few studies have examined the impacts of ocean acidification on Trichodesmium grown at low P concentrations using non-steady-state batch cultures. Here we cultured Trichodesmium using P-limited continuous cultures (chemostat) to mimic steady-state oceanic low P condition, and used comparative NGS-derived Trichodesmium transcriptome profiling (RNA-seq) analysis to find differentially expressed genes and cellular pathways in response to acidification. mRNA profiles of phosphorus limited Trichodesmium cultured at 400 µatm pCO2 (LP_400) and 750 µatm pCO2 (LP_800)