Fusarium head blight (FHB), is a destructive disease of small grain crops, with worldwide economic and health impacts. FHB is mainly caused by Fusarium graminearum, a fungus which infects the cereal inflorescence during anthesis and grain development, leading to severe losses in grain yields and quality. Resistance to FHB is a complex and quantitative trait largely influenced by genotype-environment interactions. While the genetic basis of FHB resistance has been extensively studied in bread wheat, poor information is available on durum wheat. The aim of this work was to develop a RIL (Recombined Inbred Lines) population suitable for studying FHB resistance in durum wheat, and obtaining a genetic linkage map by using microsatellite and SNP markers. A FHB-resistant bread wheat accession, (02-5B-318) and the FHBsusceptible durum wheat cv. Saragolla were crossed obtaining a total of 421 lines by advancing random individual F2 plants to F7 generation by Single Seed Descent (SSD). The classification in hexaploid and tetraploid lines was determined by validating each line for the presence or the lack of D-genome chromosome with a set of 14 single band, D genome-specific gSSR markers. In this way, two distinct RIL populations were obtained, one of bread, and one of durum wheat, consisting 136 lines; the remaining lines showed D genome chromosomes segregation. A set of 260 microsatellite markers was chosen for covering each chromosome and analysed between the two parents for polymorphism. As expected, the level of polymorphism was higher for genomic SSRs (65.4%) than for EST-derived ones (34.6%). The 188 polymorphic primer pairs originated 280 markers with a number of alleles per locus ranging from one to five. The work is currently going on by genotyping the durum RILs with the polymorphic markers, in order to develop the genetic linkage map. The evaluation of resistance to Fusarium graminearum has been conducted in two replicated field trials in Valenzano (BA) and Bologna (SIS). Pathogenicity assay was conducted by artificially spray-inoculating plants during anthesis with a 106 /mL macroconidia suspension, and recording the severity of the disease after two weeks according to the scale of Perry et al. (1984). The pathogenicity assay on the two parents, 02-5B-318 and Saragolla, was carried out in Bari, while the evaluation of resistance on the durum RIL population was carried out in Bologna where it was observed a segregation for this trait. The future work will proceed with the saturation of the genetic map by using a 90K Illumina Infinium assay for SNP markers, the identification of QTL for FHB resistance and associated markers that will be useful for the positional cloning and the transfer of resistance to susceptible cultivars.
DEVELOPMENT OF A DURUM WHEAT SEGREGANT POPULATION FOR FUSARIUM HEAD BLIGHT RESISTENCE
GIANCASPRO A;
2013-01-01
Abstract
Fusarium head blight (FHB), is a destructive disease of small grain crops, with worldwide economic and health impacts. FHB is mainly caused by Fusarium graminearum, a fungus which infects the cereal inflorescence during anthesis and grain development, leading to severe losses in grain yields and quality. Resistance to FHB is a complex and quantitative trait largely influenced by genotype-environment interactions. While the genetic basis of FHB resistance has been extensively studied in bread wheat, poor information is available on durum wheat. The aim of this work was to develop a RIL (Recombined Inbred Lines) population suitable for studying FHB resistance in durum wheat, and obtaining a genetic linkage map by using microsatellite and SNP markers. A FHB-resistant bread wheat accession, (02-5B-318) and the FHBsusceptible durum wheat cv. Saragolla were crossed obtaining a total of 421 lines by advancing random individual F2 plants to F7 generation by Single Seed Descent (SSD). The classification in hexaploid and tetraploid lines was determined by validating each line for the presence or the lack of D-genome chromosome with a set of 14 single band, D genome-specific gSSR markers. In this way, two distinct RIL populations were obtained, one of bread, and one of durum wheat, consisting 136 lines; the remaining lines showed D genome chromosomes segregation. A set of 260 microsatellite markers was chosen for covering each chromosome and analysed between the two parents for polymorphism. As expected, the level of polymorphism was higher for genomic SSRs (65.4%) than for EST-derived ones (34.6%). The 188 polymorphic primer pairs originated 280 markers with a number of alleles per locus ranging from one to five. The work is currently going on by genotyping the durum RILs with the polymorphic markers, in order to develop the genetic linkage map. The evaluation of resistance to Fusarium graminearum has been conducted in two replicated field trials in Valenzano (BA) and Bologna (SIS). Pathogenicity assay was conducted by artificially spray-inoculating plants during anthesis with a 106 /mL macroconidia suspension, and recording the severity of the disease after two weeks according to the scale of Perry et al. (1984). The pathogenicity assay on the two parents, 02-5B-318 and Saragolla, was carried out in Bari, while the evaluation of resistance on the durum RIL population was carried out in Bologna where it was observed a segregation for this trait. The future work will proceed with the saturation of the genetic map by using a 90K Illumina Infinium assay for SNP markers, the identification of QTL for FHB resistance and associated markers that will be useful for the positional cloning and the transfer of resistance to susceptible cultivars.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
