Diversity and geographical distribution of seed lipoxygenase-1 thermostability types in barley

摘要

To understand the diversity in the thermostability of the seed lipoxygenase-1 (LOX-1), 1040 cultivars of worldwide barley (Hordeum vulgare ssp. vulgare) genetic resources were investigated. The relative thermostability of LOX-1 (LOX-RTS) in these lines showed a bimodal frequency distribution and these lines were categorized into the high and low thermostability types (H-type and L-type, respectively). The H-type lines predominated in the wild progenitor, ssp. spontaneum. The geographical distribution of these types in the cultivars was surveyed. The frequencies of the H- and L-types were almost equal to one another in southwestern Asia. The occurrence of the H-type predominated in eastern Asia and Africa, whereas in Europe and Turkey, the L-type did. The predominance of the L-type in Europe and Turkey can be understood through the hypothesis that the Fertile Crescent domestication contributed the majority of diversity in Europe. The uneven geographical distribution of the LOX-1 thermostability types in the cultivars may reflect a polyphyletic origin of barley.