Characterisation of the promoter region of Glu~lBx7 gene from overexpressing lines of an old Hungarian wheat variety.

摘要

One of the old Hungarian wheat populations, Bankuti 1201 has been the focus of research attention in the last several years. Based on these studies, Bankuti 1201 contains lines with different storage protein composition and different rheological properties. High level of unextractable polymeric protein and Bx7 overexpression was detected in certain Bankuti 1201 lines using HPLC. All of these lines possess 7+8 subunits on Glu-IB locus and resulted in stronger dough properties. To develop molecular marker to identify Bx7 overexpression the promoter region of Glu-lBx7 gene from normal and overexpressing Bankuti 1201 lines was cloned and sequenced. Promoter sequence of normal expressing line was identical to the sequence of the Bx7 promoter from cv. Cheyenne, a genotype with normal expression level. In the promoter sequence, derived from lines overexpressing Glu-lBx7, a short insertion compared to the Cheyenne promoter sequence was identified. Similar insertion is present in Glenlea, a known Bx7 overexpressing genotype. PCR assay was developed for the detection of this insertion. Genotypes with normal expression level of subunit 7 (Chinese Spring) yielded the shorter fragment. Genotypes overexpressing subunit 7 (Red River and several Bankuti 1201 lines) apparently carry the longer promoter. The correlation between the high Bx7 content and the presence of the insertion was 100%. It seems, that identification of the Bx7 overexpressing varieties is possible based on this assay.