Antioxidant Enzyme, Transcriptomic, and Metabolomic Changes in Lily (Lilium spp.) Leaves Induced by Aphis gossypii Glover

Cotton aphids (<i>Aphis gossypii</i> Glover) cause harm by feeding on phloem sap and spreading plant viruses to lily. Understanding the mechanisms by which aphids infest lily plants is crucial for effective aphid management and control. In this study, we investigated the activity of antioxidants, integrated nontargeted metabolomes and transcriptomes of lilies infested by cotton aphids to explore the changes in lily leaves. Overall, the results indicated that the catalase (CAT) activity in the leaves of the lily plants was greater than that in the leaves of the control plants. A comprehensive identification of 604 substances was conducted in the leaves. Furthermore, the differentially abundant metabolite analysis revealed the enrichment of phenylalanine metabolism and α-linolenic acid metabolism. Moreover, 3574 differentially expressed genes (DEGs), whose expression tended to increase, were linked to glutathione metabolism and phenylpropanoid biosynthesis. In addition, the integrated analysis revealed that the defensive response of lily leaves to aphids is manifested through antioxidant reactions, phenylpropane and flavonoid biosynthesis, and α-linolenic acid metabolism. Finally, the key metabolites were CAT, glutathione, coumaric acid, and jasmonic acid, along with the key genes chalcone synthase (<i>CHS</i>), phenylalanine ammonia-lyase (<i>PAL</i>), and 12-oxo-phytodienoic acid reductase (<i>OPR</i>). Accordingly, the findings of this research elucidate the molecular and metabolic reactions of <i>A. gossypii</i> in lily plants, offering valuable insights for developing aphid resistance strategies in lily farming.