title: Fine Mapping and Characterization of Candidate Genes that Control Resistance to Cercospora sojina K. Hara in Two Soybean Germplasm Accessions.
abstract: Frogeye leaf spot (FLS), caused by the fungus Cercospora sojina K. Hara, may cause a significant yield loss to soybean growers in regions with a warm and humid climate. Two soybean accessions, PI 594891 and PI 594774, were identified to carry a high level of resistance similar to that conditioned by the Rcs3 gene in 'Davis'. Previously, we reported that the resistance to FLS in these two plant introductions (PIs) was controlled by a novel gene (s) on chromosome 13 that is different from Rcs3. To fine-map the novel FLS resistance gene(s) in these two PIs, F2: 3 seeds from the crosses between PI 594891 and PI 594774, and the FLS susceptible genotype 'Blackhawk' were genotyped with SNP markers that were designed based on the SoySNP50k iSelect BeadChip data to identify recombinant events and locate candidate genes. Analysis of lines possessing key recombination events helped narrow down the FLS-resistance genomic region in PI 594891 from 3.3 Mb to a 72.6 kb region with five annotated genes. The resistance gene in PI 594774 was fine-mapped into a 540 kb region that encompasses the 72.6 kb region found in PI 594891. Sequencing five candidate genes in PI 594891 identified three genes that have several mutations in the promoter, intron, 5', and 3' UTR regions. qPCR analysis showed a difference in expression levels of these genes in both lines compared to Blackhawk in the presence of C. sojina. Based on phenotype, genotype and haplotype analysis results, these two soybean accessions might carry different resistance alleles of the same gene or two different gene(s). The identified SNPs were used to develop Kompetitive Allele Specific PCR (KASP) assays to detect the resistance alleles on chromosome 13 from the two PIs for marker-assisted selection.
authors.affiliation: Center for Applied Genetic Technologies & Department of Crop and Soil Sciences, University of Georgia, Athens, Georgia, United States of America.
authors.forename: Anh-Tung
authors.initials: AT
authors.lastname: Pham
authors.affiliation: Center for Applied Genetic Technologies & Department of Crop and Soil Sciences, University of Georgia, Athens, Georgia, United States of America.
authors.forename: Donna K
authors.initials: DK
authors.lastname: Harris
authors.affiliation: Department of Plant Pathology, University of Georgia, Griffin, Georgia, United States of America.
authors.forename: James
authors.initials: J
authors.lastname: Buck
authors.affiliation: Center for Applied Genetic Technologies & Department of Crop and Soil Sciences, University of Georgia, Athens, Georgia, United States of America.
authors.forename: Aaron
authors.initials: A
authors.lastname: Hoskins
authors.affiliation: Center for Applied Genetic Technologies & Department of Crop and Soil Sciences, University of Georgia, Athens, Georgia, United States of America.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Serrano
authors.affiliation: Center for Applied Genetic Technologies & Department of Crop and Soil Sciences, University of Georgia, Athens, Georgia, United States of America.
authors.forename: Hussein
authors.initials: H
authors.lastname: Abdel-Haleem
authors.affiliation: Soybean Genomics and Improvement Laboratory, United States Department of Agriculture-Agricultural Research Service, Beltsville, Maryland, United States of America.
authors.forename: Perry
authors.initials: P
authors.lastname: Cregan
authors.affiliation: Soybean Genomics and Improvement Laboratory, United States Department of Agriculture-Agricultural Research Service, Beltsville, Maryland, United States of America.
authors.forename: Qijian
authors.initials: Q
authors.lastname: Song
authors.affiliation: Center for Applied Genetic Technologies & Department of Crop and Soil Sciences, University of Georgia, Athens, Georgia, United States of America.
authors.forename: H Roger
authors.initials: HR
authors.lastname: Boerma
authors.affiliation: Center for Applied Genetic Technologies & Department of Crop and Soil Sciences, University of Georgia, Athens, Georgia, United States of America.
authors.forename: Zenglu
authors.initials: Z
authors.lastname: Li
mesh_terms: D001203:Ascomycota / Q000472:pathogenicity*; D017343:Genes, Plant; D013025:Glycine max / Q000235:genetics / Q000382:microbiology*