Storage Protein And SSR Analysis Of Wheat Landrances With High Resistance To Scab

Wheat scab or Fusarium head blight (HFB), mainly caused by Fusarium graminearum Schwabe, is one of the most destructive disease in warm and humid regions of the world. It not only significantly reduces grain set and grain weight but also effects the end-use quality. Severe, mycotoxin contamination of the seeds is harmful to humans and livestock. The use of resistant cultivars is the best way to control the disease. Therefore, It is very important to search for scab resistant sources and characterize resistance genes in various resources. One Chinese wheat cultivar, Sumai 3, is considered to be the most useful genetic source for breeding of scab resistance wheat cultivar. In China, 27 more than 30 highly resistance landraces have been identified, which were equal to or superior than Sumai 3. It is essential to identify the resistance genes for scab from the various sources, integrating the various resistance genes to improve combined resistance in wheat. In this study, the genetic diversity among 20 wheat landrances with high resistance to scab was investigated by using SSR. And the same time, using A-PAGE and SDS-PAGE methods, the gliadin and HMW-glutenin subunits of these varieties were analyzed.1. In order to investigate the variation of gliadin and analyze the genetic difference between genotypes of 23 wheat landrances with high resistance to scab, the acid polyacrylamide gel eletrophoresis (A-PAGE) was used. There were 20 gliadin genotypes in the 23 cultivars. A total of 39 gliadin bands with different relative mobility were observed, while 31 bands (86.8%) were polymorphic. These results suggest that abundant gliadin variations exist among thse cultivars. The genetic relationships wereestimated by a UPGMA cluster analysis of GS matrix. It showed that some landrances of same origin clustered together.2. Using sodium dodeeyl sulphate-polyacrylamid gel electrophoric (SDS-PAGE), the HMW-GS (high-molecular-weight glutenin subunits) of 23 wheat Landrances with high resistance to scab were analyzed. The high level of genetic variations at Glu-1 locus was observed. 9 subunit patterns and 6 subunit combinations were detected, respectively. The quality scores of each cultivar at Glu-1 have been calculated according to the methods described by Payne et al (1987). The quality scores of these cultivars were quite low, ranging from 2 to 9, with the mean of 6.0. There were 3 landrances with higher quality scores.3. Using 40 SSR markers with representing all 21 chromosomes of wheat genomes, the genetic diversity among 20 wheat landraces highly resistant to head scab and 4 wheat lines highly susceptible to head scab were evaluated. And revealed a total of 279 alleles with mean of 6.98 alleles per SSR marker. The total of SSR markers were polymorphic among 24 genotypes. The genetic similarity among highly resistance landraces, and these landraces with highly susceptible wheat cultivars 'Chinese Spring' and 'Fan 6'were very high, but the genetic diversity of these landraces with 1 highly susceptible lines, synthetic wheat 'RSP' was much higher. These results suggested that it is possible to tag the genes resistant to wheat scab in these highly resistant wheat landraces by choosing synthetic wheat 'RSP' as another parent for gene mapping.