Prochlorococcus, the dominant cyanobacterium in the oligotrophic ocean, possesses a streamlined genome and depends on interactions with heterotrophic bacteria for survival under various stressors. While the role of 'helper' bacteria in mitigating oxidative stress is established, the mechanisms enabling its long-term survival under nitrogen (N) limitation remain poorly characterized. Here, we employ a multi-omics approach - integrating transcriptomics and proteomics - to investigate the physiolog