Menadione sodium bisulphite: a novel plant defence activator enhances local and systemic resistance to infection by Leptosphaeria maculans in oilseed rape

8 pages, 5 figures, 4 tables.-- Printed version published Aug 2003. ; Pretreatment of the first true leaves of oilseed rape plants (Brassica napus cv. Bristol) with menadione sodium bisulphite (MSB) locally and systemically induced resistance, as shown by reduced lesion size and number, to infection by the fungal pathogen Leptosphaeria maculans, the causal agent of stem canker. Using a known systemic activator of salicylic acid-dependent PR-1 induction, acibenzolar-S-methyl (BTH; S-methylbenzo[1,2,3]thiadiazole-7-carbothiate) as a comparison, real-time PCR expression analysis of genes encoding a pathogenesis-related protein 1 (PR-1) and an ascorbate peroxidase (APX) demonstrated a systemic enhancement of APX expression in MSB-pretreated plants, with no effect on PR-1 expression, suggesting augmented reactive oxygen species production in MSB-pretreated plants. The results demonstrate MSB to be an effective resistance activator in oilseed rape, and potentially useful for the control of stem canker. ; This work was funded in part by grant-aided support from Consejo Superior de Investigaciones Científicas (CSIC) of Spain and a study-visit grant from the Royal Society. The second author receives funding from the Royal Society as part of an International Exchange Fellowship. Rothamsted Research receives grant-aided support from the Biotechnology and Biological Sciences Research Council of the UK.