Molecular Identification of Alleles on Lpx-B1 Locus and Lipoxygenase Activity in Durum Wheat ( Triticum turgidum L.)

Abstract

Lipoxygenase(LOX) has a close relationship to the processing quality of flour products in durum wheat(Triticum turgidum L.). Activity of LOX is greatly influenced by the locus of Lpx-B1. The Lpx-B1 alleles in 167 durum wheat varieties from different countries or regions were identified using gene-specific primers, and the Lpx-B1 genotypes were analyzed based on LOX activity data. The LOX activity varied greatly in the 167 varieties, ranging from 0.20 to 7.98 AU min–1 g–1. On Lpx-B1.1 locus, three alleles(Lpx-B1.1a, Lpx-B1.1b, and Lpx-B1.1c) were identified with frequencies of 55.1%, 7.8%, and 37.1%, respectively. Loci Lpx-B1.2 and Lpx-B1.3 were always reciprocally present in varieties, in which Lpx-B1.2 was presented in 146 varieties and Lpx-B1.3 in the remaining 21 varieties. This result indicates the allelic possibility of Lpx-B1.2 and Lpx-B1.3. In the three Lpx-B1.1 genotypes, the Lpx-B1.1b varieties had significantly higher LOX activity than the Lpx-B1.1a and Lpx-B1.1c varieties, and varieties carrying Lpx-B1.1c allele possessed the lowest LOX activity. The LOX activity in Lpx-B1.3 genotypes was significantly higher than that in Lpx-B1.2 genotypes. A total of six genotypic combinations were found on the three Lpx-B1 loci in 167 varieties. Among them, Lpx-B1.1b/Lpx-B1.3 combination had the highest LOX activity and combinations of Lpx-B1.1c/Lpx-B1.2 and Lpx-B1.1c/Lpx-B1.3 had the lowest LOX activity. These results are informative to quality breeding of durum wheat.