The link between phosphate starvation-triggered anthocyanin biosynthesis and jasmonate-driven regulation in tomato

Phosphate Starvation Response (PSR) in plants integrates inorganic phosphate (Pi) sensing with hormonal and metabolic reprogramming. Recent evidence supports a PSR-jasmonate (JA)-anthocyanin axis in which the PSR-associated PHOSPHATE STARVATION RESPONSE (PHR)/PHR-like-SYG1-PHO81-XPR1-inositol pyrophosphate 8 (PHR/PHL-SPX-InsP8) module gates transcriptional activation, while the core JA components JASMONATE ZIM-DOMAIN (JAZ) and MYELOCYTOMATOSIS 2 (MYC2) mediate hormone-induced activation of secondary metabolism. In Solanum lycopersicum, PHR/PHL transcription factors (TFs) serve as core PSR hubs, with expanded regulatory networks and InsP-associated control layers that tune SPX buffering and transcriptional output. Downstream, JA signaling and MYC2-dependent transcription interface with anthocyanin regulators, including key MYB and bHLH TFs that form the MYB-basic helix-loop-helix (bHLH)-WD40 repeat (MBW) complex, thereby regulating tissue capacity for pigmentation under Pi starvation (PiS). Anthocyanin-rich tomato cultivars such as 'Indigo Rose' exemplify how genetic configuration can enhance MBW responsiveness and potentiate pigment accumulation under PiS. Here, we collate recent advances linking PSR gating, JA response, and anthocyanin biosynthesis regulation in tomato, and propose a working model with testable predictions to accelerate causal validation, and enable breeding strategies targeting phosphorus use efficiency and nutritional quality.