Examining volatile compounds in healthy and mite induced leaf galls of wild type and mutant Jasminum auriculatum Vahl. lines offer clues on pest resilience

In the pursuit of enhancing genetic diversity in Jasminum auriculatum, which allows adaptability to undesirable environmental changes, mutagenesis stands out as a promising strategy. This study explored metabolomes of two Jasminum auriculatum mutants MM-AJR-1 (Muthu Mullai - Aceria jasmini Resistance-1) and MM-AJR-2 (Muthu Mullai - Aceria jasmini Resistance-2) which were developed via 15 Gy gamma irradiation and 20 mM EMS treatment, respectively. These lines demonstrated resistance to Aceria jasmini, a major non-insect pest of Jasminum auriculatum. Using Gas Chromatography-Mass Spectrometry (GC-MS), comparative profiling of healthy and Aceria jasmini infested leaves revealed a set of unique bioactive metabolites, including trans-cinnamic acid, propenoic acid, fatty acids, phytosterols (sitosterol and stigmasterol) and antioxidant compounds (α-tocopherol). Additionally, biochemical analyses confirmed elevated levels of defense enzymes namely, phenylalanine ammonia lyase, peroxidase and polyphenol oxidase in the mutant lines. Scanning Electron Microscopy (SEM) of leaf epidermis further revealed a well-structured and resilient trichome architecture in resistant mutants, contrasting the disrupted surfaces in the wild type. These findings highlight the multifaceted biochemical and anatomical defense strategies in the mutants establishing them as promising candidates for breeding insect-resistant Jasmine cultivars.