Novel gene loci associated with susceptibility or cryptic quantitative resistance to Pyrenopeziza brassicae in Brassica napus

A - Papers appearing in refereed journals

2023. Novel gene loci associated with susceptibility or cryptic quantitative resistance to Pyrenopeziza brassicae in Brassica napus. Theoretical and Applied Genetics. 136, p. 71.


Key message
Quantitative disease resistance (QDR) controls the association of the light leaf spot pathogen with Brassica napus; four QDR loci that were in linkage disequilibrium and eight gene expression markers were identified.

Quantitative disease resistance (QDR) can provide durable control of pathogens in crops in contrast to resistance (R) gene-mediated resistance which can break down due to pathogen evolution. QDR is therefore a desirable trait in crop improvement, but little is known about the causative genes, and so it is difficult to incorporate into breeding programmes. Light leaf spot, caused by Pyrenopeziza brassicae, is an important disease of oilseed rape (canola, Brassica napus). To identify new QDR gene loci, we used a high-throughput screening pathosystem with P. brassicae on 195 lines of B. napus combined with an association transcriptomics platform. We show that all resistance against P. brassicae was associated with QDR and not R gene-mediated. We used genome-wide association analysis with an improved B. napus population structure to reveal four gene loci significantly (P = 0.0001) associated with QDR in regions showing linkage disequilibrium. On chromosome A09, enhanced resistance was associated with heterozygosity for a cytochrome P450 gene co-localising with a previously described locus for seed glucosinolate content. In addition, eight significant gene expression markers with a false discovery rate of 0.001 were associated with QDR against P. brassicae. For seven of these, expression was positively correlated with resistance, whereas for one, a HXXXD-type acyl-transferase, negative correlation indicated a potential susceptibility gene. The study identifies novel QDR loci for susceptibility and resistance, including novel cryptic QDR genes associated with heterozygosity, that will inform future crop improvement

Year of Publication2023
JournalTheoretical and Applied Genetics
Journal citation136, p. 71
Digital Object Identifier (DOI)
Open accessPublished as ‘gold’ (paid) open access
FunderBiotechnology and Biological Sciences Research Council
Department of Environment, Food and Rural Affairs
Funder project or code14 ERA-CAPS Mechanistic Analysis of Quantitative Disease Resistance in Brassica by Associative Transcriptomics
Brassica Rapeseed And Vegetable Optimisation (BRAVO)
Publisher's version
Output statusPublished
Publication dates
Online23 Mar 2023
Publication process dates
Accepted19 Dec 2022

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