Exploring Root Architecture as a Defense against Soil-Borne Pathogens
CSANR Project 131
Soil-borne pathogens, particularly root-lesion nematodes (Pratylenchus spp.), Fusarium spp., and Rhizoctonia spp. are a major constraint to grain production in the Pacific Northwest. Yield losses associated with these pathogens rages from 20-60% in infested fields. Symptoms often mimic drought or nutrient deficiencies because of plant root damage. The options available to growers to control pathogen populations that are environmentally and economically sustainable are limited. Soil-borne pathogens are associated with reduced tillage and need to be controlled in order to expand this soil conserving farming practice. Resistance to Pratylenchus has been identified in a wheat landrace accession, AUS28451, and correlated with root lignin content. Root lignin has been shown to act as a physical barrier against fungal penetration. It is therefore likely accession AUS28451 also has some resistance to Fusarium and Rhizoctonia. A single source of resistance to multiple pathogens will be a useful tool for wheat breeders since resistance to all three pathogens is lacking in our adapted varieties and introgression from multiple sources would be a challenging task. As many studies have shown soil-borne resistance is often quantitative, identifying molecular markers associated with the suspected mechanism of resistance will assist in breeder efforts. Once resistance to these soil-borne pathogens becomes available, growers will be able to reduce chemical and cost inputs for wheat production and promote sustainability.