Duplication of the Bx7 high-molecular-weight glutenin subunit gene in bread wheat (Triticum aestivum L.) cultivar 'Red River 68'

SDS-PAGE analysis of seed proteins of the cultivar 'Red River 68' showed a considerably higher staining intensity of the band corresponding to HMW-GS Bx7 relative to the equivalent band in the cultivars 'Chinese Spring' and 'Cheyenne'. Southern blots of restriction enzyme fragments from DNA of these three cultivars were analyzed densitometrically to reveal that the band corresponding to the Bx7 gene of 'Red River 68' had a double staining intensity compared to the equivalent bands from the other two cultivars, which indicates that in 'Red River 68' a duplication of the Bx7 gene has occurred. Although the possibility of the gene copy being a pseudogene was not ruled out, the greater amount of protein corresponding to Bx7 in 'Red River 68' most likely is in accord with an increase in active gene number. SDS-PAGE analysis of the proteins showed also that the mobility of Bx7 in 'Cheyenne' was slightly different from the mobilities of the Bx7 subunits of 'Red River 68' and 'Chinese Spring'. The same difference was observed at the gene level by PCR amplification of the genes encoding these subunits.