Capsaicin Without Capsicum: A Computational Framework for Cross-Species Capsaicinoid Pathway Engineering Across 17 Plant Species in Four Engineering Tiers

The capsaicinoid biosynthesis pathway is modular. The upstream phenylpropanoid branch (PAL, C4H, 4CL, HCT, COMT) is universally conserved across all vascular plants. Only two enzymes are strictly pepper-specific: pAMT and Pun1/AT3 (capsaicin synthase). We present a computational framework for installing capsaicinoid biosynthesis in 17 non-Capsicum species across four engineering tiers. Ortholog analysis confirms all upstream genes as endogenous in tomato (66-98% protein identity); only pAMT and Pun1 must be introduced. FBA predicts 2,601-1,246,644 SHU for tomato and 2,258-1,110,413 SHU for eggplant. Strawberry achieves 64,260 SHU maximum (64.3% feasibility). The ESM2-optimized Pun1 triple mutant (S39L+L345G+C175S) is organism-independent. Five of seven platform modules transfer unchanged. Companion paper: doi:10.5281/zenodo.23743695. Platform: platform.scovillesplice.farm