Wheat chromosomal structure

Wheat, barley, and rye are classified in the same subfamily (Festucoideae) and tribe (Triticeae) of the grass family (Gramineae), and this close relationship is reflected in the structures of their prolamin storage proteins. Only in wheat, however, do these proteins form a cohesive mass (gluten). Barley and rye are diploids, each with seven pairs of chromosomes, while wheat species are diploid, tetraploid, or hexaploid (Figure 3.14). 

O. D. Anderson, B. Cassidy, J. Steffen, J. Dvorak, and F.C. Greene, 1991. Structure of the high-and low- molecular-weight gene families of the homoeologous group 1 chromosomes of the hexaploid bread wheat cultivar Cheyenne, pp. 512-519 in Gluten Proteins 1990. W. Bushuk and R. Tkachuk, eds. Am. Assoc. Cereal Chem. St. Paul, MN. 

In the works of A. Konarev (Konarev et al. 1999 Konarev et al., 2004) shows in detail the variability of inhibitors of trypsin-like proteinases in cereals due to resistance to various grain pests. So in wheat trypsin inhibitors are represented by several genetically independent systems of proteins controlled by the genome and B chromosomes ID (endosperm), 3Dp (aleurone layer), IDS and 3Ap (leaf). Trypsin inhibitors of rye are controlled chromosome 3R and barley 3H. The most complex structure of inhibitors was wheat leaves, with the genomic formula AABBDD. In general, it is the sum of the spectra of trypsin inhibitors from several tetraploid (T. turgidum) (AABB) and (Aegilops tauschii Coss.) (DD) (Konarev, 1986 Konarev et al., 2004). 

In addition to the trypsin inhibitors are very interesting inhibitors of chymotrypsin and subtilisin, which are the most heterogeneous structure and variability of all species of wheat and corn and barley, which are controlled by fifth chromosome, while the wheat and rye - I homoeologous group of chromosomes of different genomes. In diploid wheat, a number of species (T, timopheevii) identified the protein components capable of inhibiting both subtilisin and chymotrypsin, which are characterized by low variability (Konarev et al., 2004). 

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