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Genome-based identification of genes involved in pathogen interactions with Brassica crops

Chinthani Karandeni-Dewage: University of Hertfordshire

<div>A wealth of genomic information, deposited in public databases, is available to identify candidate genes that contribute to interactions between crops and their pathogens. Of interest to us are pathogens that pose global threats to production of <em>Brassica</em> oilseed and vegetable crops, including <em>Brassica napus</em>, <em>Brassica juncea</em>, <em>Brassica rapa</em> and <em>Brassica oleracea</em>. We have used published and in-house genome sequences to determine the distribution of genes encoding leucine-rich repeat (LRR) receptors in the genome of <em>B. napus</em>. Specific attention was given to a resistance (<em>R</em>) gene cluster on chromosome A7 that operates against the phoma stem canker pathogen <em>Leptosphaeria maculans</em>. Tests for positive selection were used to decrease the number of candidate LRR genes, which can be used as cloning and breeding targets. In addition, the genomic intervals of known major and quantitative trait loci for resistance against <em>L. maculans</em>, <em>Sclerotinia sclerotiorum</em> and the clubroot pathogen <em>Plasmodiophora brassicae</em> were used to determine the specific contribution of genes encoding nucleotide-binding, secreted or transmembrane LRR receptors. Furthermore, work is proceeding to better understand molecular components of compatibility of <em>B. napus</em> to <em>L. maculans</em> and its sister species <em>Leptosphaeria biglobosa</em>. This research is of benefit to our academic and industry colleagues working on plant breeding.</div>