Identification of a Differentially Expressed TIR-NBS-LRR Gene in a Major QTL Associated to Leaf Rust Resistance in Salix.

Martin T, Rönnberg-Wästljung AC, Stenlid J, Samils B

PLoS ONE 11 (12) e0168776 [2016-12-21; online 2016-12-21]

An earlier identified major quantitative trait locus for resistance towards the willow leaf rust fungus Melampsora larici-epitea in a Salix viminalis x (S. viminalis × S. schwerinii) population was used to identify potential resistance genes to the rust pathogen. Screening a genomic bacterial artificial chromosome library with markers from the peak position of the QTL region revealed one gene with TIR-NBS-LRR (Toll Interleukin1 Receptor-Nucleotide Binding Site-Leucine-Rich Repeat) domain structure indicative of a resistance gene. The resistance gene analog was denoted RGA1 and further analysis revealed a number of non-synonymous single nucleotide polymorphisms in the LRR domain between the resistant and susceptible Salix genotypes. Gene expression levels under controlled conditions showed a significantly lower constitutive expression of RGA1 in the susceptible genotype. In addition, the susceptible genotype showed a significantly reduced expression level of the RGA1 gene at 24 hours post inoculation with M. larici-epitea. This indicates that the pathogen may actively suppress RGA1 gene expression allowing a compatible plant-pathogen interaction and causing infection.

NGI Uppsala (SNP&SEQ Technology Platform) [Service]

National Genomics Infrastructure [Service]

PubMed 28002449

DOI 10.1371/journal.pone.0168776

Crossref 10.1371/journal.pone.0168776

pii: PONE-D-16-15837
pmc: PMC5176316