Biosynthetic gene clusters everywhere, but the environment selects

The in situ relevance of biosynthetic gene clusters (BGCs) remains poorly understood. We applied meta-omics to characterize BGC diversity and activity along a peatland redox gradient. From seven metagenomes, we recovered 9,694 BGCs spanning diverse taxa, most lacking close relatives in reference databases, indicating extensive novelty. Only 9-27% of this potential was expressed in situ, with Acidobacteriota, despite moderate repertoires, accounting for over half of all BGC transcription. "Talented producers" with up to 24 clusters were largely silent, and expression was inversely related to BGCs per genome. Acidobacteriota and other oligotrophic taxa expressed most of their BGCs, whereas copiotrophic Pseudomonadota expressed a few, suggesting that life-history and stress-responsive regulation govern activation. PKS and terpene BGCs expression was enriched in genomes expressing markers of aerobic respiration and stress, whereas RiPPs were associated with antimicrobial resistance, stationary phase and stress. Thus, although BGCs are widespread, environmental constraints determine which are realized.