Increased resistance of a maize mutant lacking the 9-lipoxygenase gene, ZmLOX3, to root rot caused by Exserohilum pedicellatum

Plant oxylipins, produced via the lipoxygenase (LOX) pathway, function as signals in defence and development. Previous research showed that maize (Zea mays L.) mutants lacking function of one of their 9-LOX genes, ZmLOX3, had decreased levels of susceptibility to several fungal foliar pathogens. In this study, lox3-4 mutants of maize displayed less root and mesocotyl necrosis caused by Exserohilum pedicellatum, when compared with the corresponding wild type near isogenic lines in three parent lines (B73, FR2128B and CML176B). These results further support the hypothesis that a specific plant 9-LOX isoform mediates susceptibility of maize to fungal pathogens.