Genomic basis of resistance to disease-causing fungus in lodgepole pine

A combination of GWAS and RNA-seq approaches were used to study the genomic basis of host resistance to Dothistroma needle blight (DNB) caused by the fungus Dothistroma septosporum in lodgepole pine. This pathogen is increasing in impact in western Canada as climates warm. As Dothistroma septosporum is a native pathogen that has likely co-evolved with its conifer hosts in North America, naturally occurring resistance is expected. Heritable resistance to Dothistroma has been observed in progeny tests of lodgepole pine. We studied the genomic basis of resistance by: 1) evaluating transcriptional reprogramming in response to infection contrasting tolerant with susceptible genotypes using RNA-seq; 2) identifying candidate genes using a case-control GWAS design for quantitative resistance phenotypes assayed in controlled environmental conditions. The ultimate aim of this study is to develop a shortlist of causal loci underlying disease resistance, which will be used to develop the genome-assisted breeding tools for new climates.