Defense to Sclerotinia sclerotiorum in oilseed rape is associated with the sequential activations of salicylic acid signaling and jasmonic acid signaling

Signaling pathways mediated by salicylic acid (SA) and jasmonic acid (JA) are widely studied in various host–pathogen interactions. For oilseed rape (Brassica napus)–Sclerotinia sclerotiorum interaction, little information of the two signaling molecules has been described in detail. In this study, we showed that the level of SA and JA in B. napus leaves was increased with a distinct temporal profile, respectively, after S. sclerotiorum infection. The application of SA or methyl jasmonate enhanced the resistance to the pathogen. Furthermore, a set of SA and JA signaling marker genes were identified from B. napus and were used to monitor the signaling responses to S. sclerotiorum infection by examining the temporal expression profiles of these marker genes. The SA signaling was activated within 12 h post inoculation (hpi) followed by the JA signaling which was activated around 24 hpi. In addition, SA–JA crosstalk genes were activated during this process. These results suggested that defense against S. sclerotiorum in oilseed rape is associated with a sequential activation of SA signaling and JA signaling, which provide important clues for designing strategies to curb diseases caused by S. sclerotioru.

► Sclerotinia sclerotiorum infection induced a sequential activation of JA signaling from SA signaling in oilseed rape (Brassica napus).
► The SA signaling would be an early defense response or part of the innate immune reaction to the necrotrophic pathogen S. sclerotiorum infection in oilseed rape.
► The marker genes of the SA and JA signaling pathways in B. napus itself were identified and their temporal expression profiles were determined in response to S. sclerotiorum infection.