Jasmonic acid biosynthetic inhibitor ibuprofen inhibits the accumulation of ascorbic acid in strawberry fruit induced by lanthanum nitrate

By using jasmonic acid (JA) biosynthetic inhibitor ibuprofen (IBU), we investigated the roles of JA in the process of lanthanum nitrate (La(NO3)3)-regulated ascorbic acid (AsA) content and metabolic enzymes responsible for AsA metabolism in strawberry fruit. Findings demonstrated that La(NO3)3 markedly improved AsA content by enhancing the activities and transcript levels of glutathione reductase (GR), dehydroascorbate reductase (DHAR), monodehydroascorbate reductase (MDHAR) and L-galactono-1,4-lactone dehydrogenase (GalLDH), and inhibiting the activities and transcript levels of ascorbate peroxidase (APX) and ascorbic acid oxidase (AAO). In comparison with La(NO3)3 alone, all the concentrations of IBU plus La(NO3)3 markedly inhibited the activities and transcript levels of DHAR, MDHAR, GalLDH and AAO, and improved the activities and transcript levels of GR and APX, which further reduced AsA content. Besides, La(NO3)3 increased JA content and IBU decreased JA content induced by La(NO3)3. Meanwhile, the results of Pearson correlation analysis showed that JA content had significant correlations with the activities and transcript levels of DHAR, MDHAR and GalLDH. Above findings implied that La(NO3)3 induced JA production, which further increased AsA content in fruits by mainly up-regulating the activities and transcript levels of DHAR, MDHAR and GalLDH.