Indole primed defense gene expression upon pathogen infection.

qRT-PCR analysis of defense genes in detached maize leaves with pretreatment of indole (priming) for 2 d and subsequent inoculation of F. graminearum spores. Samples with (red) or without (blue) indole priming were collected at 0, 3, 6, 12, 24 and 48 h after pathogen spore inoculation. Biosynthetic genes LOX1 for JA, and An2 for maize phytoalexin were analyzed, as well as PR genes. Ef1α was used as the endogenous control. Asterisks indicate significant difference (Student’s t-test, *PPn = 3).