Submitted to: Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/18/2003
Publication Date: 4/1/2004
Citation: Xu, S.S., Khan, K., Klindworth, D.L., Faris, J.D., Nygard, G. 2004. Chromosomal location of genes for novel glutenins and gliadins in emmer wheat (triticum turgidum l. var. dicoccoides). Theoretical and Applied Genetics. Vol. 108:1221-1228. Interpretive Summary: Endosperm proteins of wheat consist predominately of two classes: glutenins and gliadins. Wheat dough quality is mainly determined by glutenins and gliadins and is strongly influenced by the allelic state of the genes controlling glutenins and gliadins. Wild emmer wheat is the tetraploid progenitor of cultivated durum and bread wheat and has many unique alleles conditioning different variants of glutenins and gliadins, which represent potential sources for improvement of quality characteristics in durum wheat. In an effort to transfer the desirable quality traits from wild emmer to durum wheat, Dr. L.R. Joppa (ARS retired) developed three sets of disomic chromosome substitution lines using wild emmer accessions Israel A, PI 481521, and PI 478742 in the background of durum wheat cultivar 'Langdon'. In each of the substitution lines, a pair of chromosomes from wild emmer wheat was substituted for a pair of native homologous chromosomes in Langdon. In this study, the glutenins and gliadins in all these substitutions and their wild emmer wheat parents were analyzed using electrophoresis. The experimental results revealed three novel glutenin variants and 29 unique gliadin proteins. The genes for these proteins were located on specific chromosomes. The identified glutenin and gliadin proteins in the substitution lines provide the basis for evaluating their effects on end-use quality of durum wheat. In addition, they are also useful biochemical markers for identifying specific chromosomes or chromosome segments during the introgression of quality traits from wild emmer wheat into cultivated wheat.
Technical Abstract: Triticum turgidum L. var. dicoccoides (DIC), known as wild emmer, is the tetraploid progenitor of durum and bread wheat. Wild emmer has many useful traits such as pest resistance, high protein content, and unique protein compositions. The glutenin and gliadin proteins of wild emmer wheat have potential for improvement of durum wheat (T. turgidum L. var. durum) quality. The objective of this study was to determine the chromosomes controlling the high molecular weight (HMW) glutenin subunits and gliadin proteins present in three T. dicoccoides accessions (Israel-A, PI-481521, and PI-478742), which were used as chromosome donors in Langdon durum-Triticum dicoccoides (LDN-DIC) chromosome substitution lines. The three T. dicoccoides accessions, their respective LDN-DIC substitution lines, and a number of controls with known HMW glutenin subunits were analyzed by SDS-PAGE, Urea/SDS-PAGE, and A-PAGE. The results revealed that all three T. dicoccoides accessions possess Glu-1A alleles that are the same as or similar to those reported previously. However, each T. dicoccoides accession had a unique Glu-B1 allele. The new Glu-B1 alleles were temporarily designated as Glu-B1be in Israel-A, Glu-B1bf in PI-481521, and Glu-B1bg in PI-478742. Results from A-PAGE indicated that there were eight, twelve, and nine unique gliadin proteins bands, which were assigned to specific chromosomes, in PI-481521, PI-478742, and Israel-A, respectively. The identified glutenin and gliadin proteins in the LDN-DIC substitution lines provide the basis for evaluating their effects on end-use quality, and they are also useful biochemical markers for identifying specific T. dicoccoides chromosomes or chromosome segments.