title: Using Genotyping by Sequencing to Map Two Novel Anthracnose Resistance Loci in Sorghum bicolor.
abstract: Colletotrichum sublineola is an aggressive fungal pathogen that causes anthracnose in sorghum [Sorghum bicolor (L.) Moench]. The obvious symptoms of anthracnose are leaf blight and stem rot. Sorghum, the fifth most widely grown cereal crop in the world, can be highly susceptible to the disease, most notably in hot and humid environments. In the southeastern United States the acreage of sorghum has been increasing steadily in recent years, spurred by growing interest in producing biofuels, bio-based products, and animal feed. Resistance to anthracnose is, therefore, of paramount importance for successful sorghum production in this region. To identify anthracnose resistance loci present in the highly resistant cultivar 'Bk7', a biparental mapping population of F3:4 and F4:5 sorghum lines was generated by crossing 'Bk7' with the susceptible inbred 'Early Hegari-Sart'. Lines were phenotyped in three environments and in two different years following natural infection. The population was genotyped by sequencing. Following a stringent custom filtering protocol, totals of 5186 and 2759 informative SNP markers were identified in the two populations. Segregation data and association analysis identified resistance loci on chromosomes 7 and 9, with the resistance alleles derived from 'Bk7'. Both loci contain multiple classes of defense-related genes based on sequence similarity and gene ontologies. Genetic analysis following an independent selection experiment of lines derived from a cross between 'Bk7' and sweet sorghum 'Mer81-4' narrowed the resistance locus on chromosome 9 substantially, validating this QTL. As observed in other species, sorghum appears to have regions of clustered resistance genes. Further characterization of these regions will facilitate the development of novel germplasm with resistance to anthracnose and other diseases.
authors.affiliation: UF Genetics Institute, University of Florida, Gainesville, Florida 32611 Department of Microbiology and Cell Science-IFAS, University of Florida, Gainesville, Florida 32611.
authors.forename: Terry
authors.initials: T
authors.lastname: J Felderhoff
authors.affiliation: UF Genetics Institute, University of Florida, Gainesville, Florida 32611 Genetics and Genomics Graduate Program, University of Florida, Gainesville, Florida 32611.
authors.forename: Lauren
authors.identifier: 0000-0002-0077-3359
authors.initials: L
authors.lastname: M McIntyre
authors.affiliation: UF Genetics Institute, University of Florida, Gainesville, Florida 32611.
authors.forename: Ana
authors.initials: A
authors.lastname: Saballos
authors.affiliation: UF Genetics Institute, University of Florida, Gainesville, Florida 32611 Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, Florida 32611 wev@ufl.edu.
authors.forename: Wilfred
authors.identifier: 0000-0002-4582-3436
authors.initials: W
authors.lastname: Vermerris
mesh_terms: D002874:Chromosome Mapping; D032461:Chromosomes, Plant / Q000737:chemistry* / Q000378:metabolism; D020231:Colletotrichum / Q000254:growth & development / Q000472:pathogenicity*; D003433:Crosses, Genetic; D060467:Disease Resistance / Q000235:genetics*; D004198:Disease Susceptibility / Q000276:immunology; D059014:High-Throughput Nucleotide Sequencing; D010935:Plant Diseases / Q000235:genetics* / Q000276:immunology / Q000382:microbiology; D020641:Polymorphism, Single Nucleotide; D040641:Quantitative Trait Loci; D045868:Sorghum / Q000235:genetics* / Q000276:immunology / Q000382:microbiology
keywords: Colletotrichum sublineola; GBS; anthracnose; sorghum