The study examined how the bioinoculant Trichoderma afroharzianum T22 influences Pisum sativum growth under iron-sufficient versus iron-deficient conditions, finding pronounced benefits—enhanced photosynthesis, Fe/N accumulation, and stress‑related gene expression—only during iron deficiency. RNA‑seq revealed distinct gene expression patterns tied to symbiosis, iron transport, and redox pathways, and microbiome profiling showed T22 reshapes the root bacterial community under deficiency, suggesting context‑dependent mutualism.