Ismail had found just a few months prior that this line was also unique in that it contained a large quantity of a specific dehydrin, while the protein could not be detected in seeds of the other lines. Once the chilling tolerance trait had been observed in the field, the trio then hypothesized that there may be a cause and effect relationship between the dehydrin protein and the chilling tolerance trait, and they set out to test the hypothesis through conventional genetics and physiological studies. They reported their initial observations and hypothesis in 1997 in the journal Crop Science. Earlier this year, they followed up with another publication in the journal Plant Physiology, where they reported results from studies involving purification of the dehydrin protein. But, a missing link in the story was that the UCR scientists did not know what gene actually controlled the production of the protein.
Genes are the hereditary units contained in the DNA of every living cell.
Not all genes are present or are expressed in each plant, however, which accounts for plant varieties that differ from one another in their ability to withstand such environmental stresses as drought, high temperatures, or cool soil conditions. The publication in Proceedings of the National Academy of Sciences provides strong evidence that the gene which directly encodes the dehydrin protein determines the expression of the protein in the seed. Solutions to problems in plant improvement are out there waiting to be discovered, and they can continue to be us ed in plant breeding, a genetic improvement method that has served humanity for centuries. The study also confirmed another hypothesis made by the UCR scientists, that the chilling tolerance conferred by the presence of the dehydrin protein in the seed seems not to act through effects on plasma membrane leakage. The plasma membrane is the semi-permeable barrier at the outer edge of cells that helps them retain minerals and other ingredients.