Gene expression in wheat containing the short arm of chromosome one of rye.

摘要

The short arm of chromosome one (1RS) from rye (Secale cereale L.) is widely distributed in wheat (Triticum aestivum L. em Thell.) breeding programs around the world. The focus of this work was to examine the behavior of the alien chromosome arm and its influence on gene expression when inserted into a wheat background in order to improve its usefulness in breeding programs.; Two-dimensional electrophoresis of a 1R(1D) wheat substitution line indicated that chromosome 1D of wheat contained sequences involved in post-transcriptional modification of proteins. 1D was also involved in suppression and induction of SSP gene expression.; Meiotic analysis indicated chromosome arm 1RS often failed to pair with its homologous arm when present in a wheat background. It appears that the rye genes act as large nonrecombining complexes when present in wheat. The low level of pairing by 1RS suggested lines containing four doses of this arm will be more stable than previously expected.; Wheat lines were selected with 0, 2 or 4 copies of 1RS. The data indicated a high correlation between dosage of the 1RS chromosome and the amount of rye SSP produced. The rRNA genes of rye had an increase in the level of dispersed rDNA, indicating increased potential for transcription. However, a combination of interactions appeared to limit the levels of expression such that only one line produced a sufficient quantity of rye rRNA to be detectable by direct assay.; In an adjunct project, techniques were developed to allow visualization of plant chromosomes with the scanning electron microscope. In addition, the techniques were adapted to allow visualization of molecular probes following in situ hybridization using nonradioactive labeling. This allowed for the detection of very small sequences.