Methyl Jasmonate Synergistically Enhances Phenolic Compounds and Reactive Oxygen Species Scavenging to Alleviate Drought-Induced Oxidative Damage in Ilex rotunda

TL;DR

Methyl jasmonate helps Ilex rotunda plants resist drought by boosting antioxidants and phenolic compounds.

Contribution

MeJA synergistically enhances drought resilience through reprogramming phenolic metabolism in Ilex rotunda.

Findings

MeJA reduced oxidative damage markers by 25% in drought-stressed Ilex rotunda.

Phenolic compounds like verbascoside and neochlorogenic acid increased by 50% and 52% with MeJA treatment.

MeJA shifted antioxidant defense from enzymatic to metabolite-based systems.

Abstract

Drought stress severely compromises the physiological integrity and secondary metabolism of medicinal plants. This study integrated physiological, biochemical, and ultra-performance liquid chromatography–tandem mass spectrometry (UPLC-MS/MS) analyses to investigate the effects of exogenous methyl jasmonate (MeJA) on drought-stressed Ilex rotunda seedlings. Drought reduced relative water content by 29% and chlorophyll by >50%, while elevating H2O2 (76%) and malondialdehyde (120%). MeJA application mitigated these impairments, reducing oxidative markers by 25% and enhancing non-enzymatic antioxidant capacity, as shown by a 74% increase in DPPH radical scavenging activity and a 141% rise in total phenolic content. Hierarchical clustering analysis (HCA), principal component analysis (PCA), and orthogonal partial least squares-discriminant analysis (OPLS-DA), and pathway mapping confirmed a significant reprogramming of the phenolic metabolome, particularly within phenylpropanoid and benzoate biosynthesis pathways. Drought + MeJA-treated plants exhibited a distinct and enriched profile compared to both well-watered control and drought-stressed groups. This reprogramming specifically elevated key hydroxycinnamates, including verbascoside and neochlorogenic acid (increased by 50% and 52%, respectively), while suppressing alternative phenolic branches. These findings demonstrate that MeJA orchestrates a shift from enzymatic scavenging to a potent metabolite-based antioxidant system, positioning it as an effective elicitor for enhancing drought resilience and enriching the high-value phytochemicals in I. rotunda.

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