Integrated transcriptomic and metabolomic analyses of a wax deficient citrus mutant exhibiting jasmonic acid-mediated defense against fungal pathogens

Abstract

Orange: Hormone protects mutant orange from fungal pathogens Elevated hormone signaling underpins fungal protection in a naturally occurring variety of orange found in China. Yunjiang Cheng from Huazhong Agricultural University in Wuhan, China, and coworkers analyzed all the genes expressed and metabolites produced by a mutant variety of ‘Newhall’ navel orange (Citrus sinensis Osbeck). The researchers found that, compared to wild-type oranges, the fungus-resistant mutant showed a decrease in both fatty acid synthesis and surface wax production, as well as an increase in synthesis of jasmonic acid, a plant hormone involved in anti-microbial defenses. The mutant seems to redirect production of fatty acids to make more jasmonic acid—and it’s this hormone that mediates the plant’s strong tolerance to fungal pathogens. This information could help agronomists breed other varieties of pest-resistant oranges that require less chemical fungicide under field and storage conditions.