Cronartium quercuum f.sp. fusiforme (Cqf) is the causal agent of fusiform rust disease of loblolly pine (Pinus taeda) and slash pine (Pinus elliottii var. elliottii). Fusiform rust is the most important disease limiting pine productivity in the southeastern U.S. Genetic resistance is the only economically feasible control method. However, gene-for-gene interactions between Cqf and its pine host can preclude effective deployment of resistance genes. To more effectively manage this pathosystem Cqf avirulence genes and alleles need to be identified and studied in natural populations. Interest in Cqf extends beyond the potential to control disease on its pine host. The life history characteristics of Cqf make it an ideal model organism for studying a number of fundamental genetic pathways such as: the gene-for-gene interaction and basal defense pathways; aecial host versus telial host resistance and pathogenicity pathways; pathways that are involved in haustorial formation and a biotrophic lifestyle; and pathways influencing major life cycle traits such as heteroecism versus autoecism. Forests are the major carbon sink in terrestrial ecosystems. They also have significant potential as a renewable plant feedstock for the production of cellulosic ethanol. One of the most attractive advantages of forest trees is the vast quantity of feedstock available. Loblolly and slash pines are the most important intensively-cultured softwood species in the southeastern U.S. where approximately 1.7 billion loblolly pine and 200 million slash pine seedlings are planted each year. Cqf genome sequence and the identification of avirulence genes would allow proper matching of planted seedling genotypes to the dominant avirulent pathogen genotypes on a site, thereby reducing plantation losses. This is especially important given the increased movement towards clonal plantings.
Genome Reference(s)
Pendleton AL, Smith KE, Feau N, Martin FM, Grigoriev IV, Hamelin R, Nelson CD, Burleigh JG, Davis JM
Duplications and losses in gene families of rust pathogens highlight putative effectors.
Front Plant Sci. 2014;5():299. doi: 10.3389/fpls.2014.00299