Biochemical evidence of chromosome homoeology among related plant genera

Two-dimensional electrophoresis as a tool for structural and genetic studies of seed proteins from Poaceae and Fagaceae

The application of two-dimensional electrophoretic procedures to structural and genetic studies of seed proteins from Poaceae (including the cultivated cereals) and Fagaceae is described. The following related problems have been considered: covalent and non-covalent association of protein subunits in multiple oligomeric structures; chromosomal locations of genes encoding seed proteins; quantitation of gene products in relation to gene expression and regulation; purification of protein components to study their homology relationships and in vitro activities; evolutionary and phylogenetic relationships; identification of genetic stocks. Isoelectric focusing, pore-gradient electrophoresis, electrophoresis at different pH's, are among the separation procedures used in the first dimension, whereas sodium dodecyl sulfate-polyacrylamide gel electrophoresis and starch-gel electrophoresis at acid pH have been the preferred second-dimensional methods. Dissociating conditions (sodium dodecyl sulfate, Nonidet P-40, or urea) and reducing conditions (2-mercaptoethanol) have been used when required.

Eyespot resistance gene Pch-1 from Aegilops ventricosa is associated with a different chromosome in wheat line H-93-70 than the resistance factor in "Roazon" wheat

The hexaploid wheat line H-93-70 carries a gene (Pch-1) that has been transferred from the wild grass Aegilops ventricosa and confers a high degree of resistance to eyespot diesease, caused by the fungus Pseudocercosporella herpotrichoides. Crosses of the resistant line H-93-70 with the susceptible wheat Pané 247 and with a 7D/7Ag wheat/Agropyron substitution line were carried out and F2 kernels were obtained. The kernels were cut transversally and the halves carrying the embryos were used for the resistance test, while the distal halves were used for genetic typing. Biochemical markers were used to discriminate whether the transferred Pch-1 gene was located in chromosome 7D, as is the case for a resistance factor present in "Roazon" wheat. In the crosses involving Pané 247, resistance was not associated with the 7D locus Pln, which determines sterol ester pattern (dominant allele in H-93-70). In the crosses with the 7D/7Ag substitution line, resistance was neither associated with protein NGE-11 (7D marker), nor alternatively inherited with respect to protein C-7 (7Ag marker). It is concluded that gene Pch-1 represents a different locus and is not an allele of the resistance factor in "Roazon" wheat.

Homoeologous chromosomal location of the genes encoding thionins in wheat and rye

Thionins are high sulphur basic polypeptides present in the endosperm of Gramineae. In wheat there are three thionins encoded by genes located in the long arms of chromosomes 1A, 1B and 1D. Rye has one thionin encoded by a gene which has been assigned to chromosome 1R after analysis of the Imperial-Chinese Spring rye-wheat disomic addition lines. Commercial varieties and experimental stocks with a 1B/1R substitution carry the thionin from rye (β R) instead of the α B thionin from wheat. The β R thionin gene is not located in the large chromosomal segment representing most of the short arm of chromosome 1R.