Molecular Plant Pathology On-Line []

Expressed sequence tags from the defense response of Brassica napus to Leptosphaeria maculans

Brian Fristensky1 Margaret Balcerzak, Daifen He and Peijun Zhang2

1Department of Plant Science, University of Manitoba, Winnipeg, R3T 2N2, Canada.

2Current address: AAFC/ECORC, 960 Carling Avenue, Ottawa K1A 0C6 Canada

Corresponding author: B. Fristensky Email:


Despite the value of canola (Brassica napus) as an oilseed crop, little molecular biology has been done on its defense responses to pathogens. To expedite the cloning of an array of defense genes from B. napus, 277 cDNAs were sequenced from a library derived using mRNA from Brassica napus leaves inoculated with an incompatible isolate of the blackleg fungus, Leptosphaeria maculans. The resultant Expressed Sequence Tags (ESTs) include sequences homologous to previously-identified defense genes, disease resistance genes, and stress-related genes, as well as genes involved in photosynthesis, metabolism and other functions not associated with defense. This EST panel will find utility in measuring gene expression in plant/pathogen interactions. Because of the wide range of ESTs identified, it may also be useful in other systems, such as stress or light regulation. Our experience with this strategy has convinced us that sequencing ESTs can be a more efficient method of gene discovery, as compared to repeated library screenings using probes from other species. Details on the EST panel can be found at