How do phthalate esters (PAEs) affect rice growth through the jasmonic acid signaling pathway?

Phthalate esters (PAEs) are widely used as plasticizers in agriculture, industry, and household products. They can leak into the environment and are frequently detected in agricultural soils. PAEs can be metabolized by crops after absorption, potentially affecting crop yield and quality. The study hypothesizes that monophthalates (mPAEs), the hydrolyzed products of PAEs, might mimic the phytohormone jasmonic acid (JA) to activate the JA signaling pathway, enhancing pest defense but inhibiting rice plant growth.

From: "Transformation metabolites of phthalate esters (PAEs) inhibited rice growth through jasmonic acid signaling pathway", Environment International, Volume 201, July 2025, 109553

The study found that exposure to dibutyl phthalate (DBP) significantly induced JA-related outcomes, including decreased larval weight (9.58–18.8%) and rice biomass (11.7–34.2%). Monobutyl phthalate (MBP), the hydrolyzed product of DBP, triggered the JA signaling pathway, evidenced by upregulated genes encoding coronatine insensitive 1 (COI1), jasmonate ZIM-domain (JAZ), and MYC2 transcription factor, and promoted phytoalexins production. MBP conjugated with isoleucine, mimicking a JA bioactivator (JA-isoleucine conjugate) to occupy the binding site of the COI1-JAZ co-receptor protein, initiating the JA signaling pathway. This mechanism was consistent across other typical PAEs, with aliphatic chain length negatively contributing to these observations. The study concludes that the transformation metabolites of PAEs elicit pest defense while inhibiting rice growth through the JA signaling pathway.