Novel Fusarium wilt resistance genes uncovered in natural and cultivated strawberry populations are found on three non-homoeologous chromosomes

Authors: PINCOT, DOMINIQUE - University Of California; FELDMANN, MITCHELL - University Of California; HARDIGAN, MICHAEL - University Of California; VACHEV, MISHI - University Of California; Henry, Peter; GORDON, THOMAS - University Of California; BJORNSON, MARTA - University Of California; RODRIGUEZ, ALAN - University Of California; COBO, NICOLAS - University Of California; FAMULA, RANDI - University Of California; COLE, GLENN - University Of California; COAKER, GITTA - University Of California; KNAPP, STEVEN - University Of California

Submitted to: Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/11/2022
Publication Date: 5/18/2022
Citation: Pincot, D.D., Feldmann, M.J., Hardigan, M.A., Vachev, M.V., Henry, P.M., Gordon, T.R., Bjornson, M., Rodriguez, A., Cobo, N., Famula, R.A., Cole, G.S., Coaker, G.L., Knapp, S.J. 2022. Novel Fusarium wilt resistance genes uncovered in natural and cultivated strawberry populations are found on three non-homoeologous chromosomes. Theoretical and Applied Genetics. 135:2121-2145. https://doi.org/10.1007/s00122-022-04102-2.
DOI: https://doi.org/10.1007/s00122-022-04102-2

Interpretive Summary: A fungal disease of strawberry, called Fusarium wilt, causes severe yield losses in California and other parts of the world. However, some strawberry cultivars do not become diseased when exposed to this pathogen; these cultivars are considered ‘resistant’ to Fusarium wilt. We demonstrate that many heirloom and wild cultivars are resistant to two strains of the Fusarium wilt pathogen and at least five resistance loci exist on three different chromosomes. At each of these loci, genes that are strong candidates for conferring resistance were identified. Lastly, we developed molecular assays to detect each locus to enable rapid identification of resistant plant genotypes. This expands the options for breeders looking to introduce known resistance genes into new cultivars.

Technical Abstract: Fusarium wilt of strawberry, a devastating soilborne disease caused by Fusarium oxysporum f. sp. fragariae, poses a significant threat to strawberry (Fragaria × ananassa) production in many parts of the world. This pathogen causes wilting, collapse, and death in susceptible strawberry genotypes. We previously identified a dominant gene (FW1) on chromosome 2B that confers resistance to race 1 of the pathogen and hypothesized that gene-for-gene resistance to Fusarium wilt was widespread in strawberry. To explore this, a genetically diverse collection of heirloom and modern cultivars and wild octoploid ecotypes were screened for resistance to Fusarium wilt races 1 and 2. Here we show that resistance to both races is widespread and that resistance to race 1 is mediated by dominant genes (FW1, FW2, FW3, FW4, and FW5) on three non-homoeologous chromosomes (1A, 2B, and 6B). The resistance proteins encoded by these genes are not yet known; however, plausible candidates were identified that encode pattern recognition receptor or other proteins known to mediate gene-for-gene resistance in plants. High-throughput genotyping assays for SNPs in linkage disequilibrium with FW1-FW5 were developed to facilitate marker-assisted selection and accelerate the development of race 1 resistant cultivars. This study laid the foundation for identifying the genes encoded by FW1-FW5, in addition to exploring the genetics of resistance to race 2 and other races of the pathogen, as a precaution to averting a Fusarium wilt pandemic.