SNP discovery and high-density genetic mapping in faba bean (Vicia faba L.) permits identification of QTLs for ascochyta blight resistance.
Ascochyta blight, caused by the fungus Ascochyta fabae Speg., is a common and destructive disease of faba bean (Vicia faba L.) on a global basis. Yield losses vary from typical values of 35-40% to 90% under specific environmental conditions. Several sources of resistance have been identified and used in breeding programs. However, introgression of the resistance gene determinants into commercial cultivars as a gene pyramiding approach is reliant on selection of closely linked genetic markers. A total of 14,552 base variants were identified from a faba bean expressed sequence tag (EST) database, and were further quality assessed to obtain a set of 822 high-quality single nucleotide polymorphisms (SNPs). Sub-sets of 336 EST-derived simple sequence repeats (SSRs) and 768 SNPs were further used for high-density genetic mapping of a biparental faba bean mapping population (Icarus×Ascot) that segregates for resistance to ascochyta blight. The linkage map spanned a total length of 1216.8 cM with 12 linkage groups (LGs) and an average marker interval distance of 2.3 cM. Comparison of map structure to the genomes of closely related legume species revealed a high degree of conserved macrosynteny, as well as some rearrangements. Based on glasshouse evaluation of ascochyta blight resistance performed over two years, four genomic regions controlling resistance were identified on Chr-II, Chr-VI and two regions on Chr-I.A. Of these, one (QTL-3) may be identical with quantitative trait loci (QTLs) identified in prior studies, while the others (QTL-1, QTL-2 and QTL-4) may be novel. Markers in close linkage to ascochyta blight resistance genes identified in this study can be further validated and effectively implemented in faba bean breeding programs.
Department of Environment and Primary Industries, Biosciences Research Division, AgriBio, Centre for AgriBioscience, 5 Ring Road, La Trobe University Research and Development Park, Bundoora, Victoria 3083, Australia.
Sukhjiwan
S
Kaur
South Australian Research and Development Institute, GPO Box 397, Adelaide, South Australia 5001, Australia.
Rohan B E
RB
Kimber
Department of Environment and Primary Industries, Biosciences Research Division, AgriBio, Centre for AgriBioscience, 5 Ring Road, La Trobe University Research and Development Park, Bundoora, Victoria 3083, Australia.
Noel O I
NO
Cogan
Department of Environment and Primary Industries, Biosciences Research Division, Grains Innovation Park, PMB 260, Horsham, Victoria 3401, Australia.
Michael
M
Materne
Department of Environment and Primary Industries, Biosciences Research Division, AgriBio, Centre for AgriBioscience, 5 Ring Road, La Trobe University Research and Development Park, Bundoora, Victoria 3083, Australia; La Trobe University, Bundoora, Victoria 3086, Australia. Electronic address: john.forster@depi.vic.gov.au.
John W
JW
Forster
School of Agriculture, Food and Wine, The University of Adelaide, Waite Campus, Glen Osmond, South Australia 5064, Australia.
Jeffrey G
JG
Paull
D001203:Ascomycota; D060467:Disease Resistance / Q000235:genetics*; D008040:Genetic Linkage; D018745:Genome, Plant; D010641:Phenotype; D010935:Plant Diseases; D020641:Polymorphism, Single Nucleotide; D040641:Quantitative Trait Loci; D026801:Synteny; D031307:Vicia faba / Q000235:genetics* / Q000276:immunology
Breeding; Comparative genetics; Disease resistance; Fungal disease; Grain legumes; Trait dissection