Defense dynamics in walnut fruit during walnut husk fly (Rhagoletis completa Cresson) infestationGrohar, Mariana Cecilia (Avtor) Zamljen, Tilen (Avtor) Medič, Aljaž (Avtor) Šimkova, Kristyna (Avtor) Vidrih, Rajko (Avtor) Veberič, Robert (Avtor) sugarsorganic acidsfatty acidskernelhuskenzymesphenolicsvolatilesethyleneRhagoletis completaJuglans regiaGC-MSHPLC-MSThe walnut husk fly is a critical pest affecting global walnut production, causing economic losses of up to 40-50%. WHF larvae feed within the walnut husk creating necrotic spots, which compromise kernel quality and marketability. In this research, the metabolic defense mechanism of the walnut fruit was targeted including several primary and secondary metabolites (sugars, volatiles, phenolics, fatty acids, carotenoids), enzymes (phenylalanine-ammonia lyase, polyphenol oxidase, peroxidase, glutamine synthetase), and antioxidant activities, using HPLC-MS/MS, GC-MS, and different spectrophotometric methods. Results revealed localized and tissue-specific metabolic responses, with significant changes in volatiles and phenolics, especially naphthoquinones and sesquiterpenes, and enzyme activities. Additionally, prolonged infestations severely affected kernel quality by reducing the content of unsaturated fatty acids and carotenoids, potentially due to oxidative stress and arrested fruit growth. Understanding these defense mechanisms is essential to mitigate economic losses and food waste, ensuring sustainable walnut production through targeted interventions and improved pre- and post-harvest treatments.20242025-01-09 07:47:40Neznano166368sl