Isolation And Characterization Of Quality Genes In Aegilops Caudata

1Two novel high-molecular-weight glutenin subunit (HMW-GS) genes designated1Cx1.1and1Cy9.1were identified in Aegilops caudata based on electrophoretic mobilityshifts comparable to those of the HMW-GSs in wheat.2Their open reading frames (ORFs) of the HMW-GS were both isolated using a pair ofdegenerate primers. Multiple sequence analysis showed that the HMW-GSs from Ae. caudatapossessed a similar primary structure to those published for HMW-GSs in wheat and itsrelative species. Additionally, they also possess some novel structural characteristics. Forexample, a tandem tripeptide existed in the central repetitive domain of1Cx1.1, and the31stamino acid in the N-terminal domain of1Cy9.1was determined to be Ala instead of Val. Theheterogeneous proteins, which were induced using in vitro E. coli expression, exhibited thesame electrophoretic mobility as HMW-GSs in Ae. caudata endosperm after removing thecoding sequence of the signal peptide from each of the two cloned ORFs. Interestingly,phylogenetic analysis showed that y-type subunits in the C genome of Ae. caudata wererelated to A genome of T. aestivum, while the x-type subunits in C genome showed differentevolutionary relationships. In addition, we also verified the source of the A, B, and Dgenomes of wheat.3Two coding sequences of LMW-GS were isolated in use of a pair of AS-primers. Thetwo LMW-GSs were named Y46-LMW1and Y46-LMW2. The deduced amino acid sequenceshowed that the two LMW-GSs were i-and m-type subunit, respectively. Highly homologywas showed between Y46and the other wheat relative species.4The coding genes of five α-gliadins, six γ-gliadins and five ω-gliadins were isolatedfrom Y46. Their sequences were similiar with the published gliadin genes. In the potentialallergenic nature, none of the published epitopes were discovered in these gliadins, itdemonstrated that gliadins in Aegilops caudata may safe for the patients of celiac disease.