Trevor Stokes, a graduate student at Washington University in St. Louis, and his mentor, Eric Richards, Ph.D., Washington University associate professor of biology in Arts & Sciences, aimed to understand what was wrong with the dwarf plant. They found that a dwarfed plant, called bal because of its shape, constantly perceives a pathogen attack even though it has the exact same DNA sequence of a non-paranoid plant. The researchers found that the differences between the two plants are not due to genes; rather, the differences are due to factors outside of genes. Moreover, such factors, like genes, can be inherited.
Stokes and Richards published their findings in the January 15, 2002 issue of Genes and Development, with co-author Barbara Kunkel, assistant professor of biology in Arts & Sciences, who studies plant-pathogen interactions.
The Richards lab specializes in epigenetics, a biological field that deals with information stored "above and beyond the gene," referring to the Greek meaning of the term. They found that the bal dwarf is caused by increasing activation of a single gene, which is otherwise identical in its basic chemical sequence compared to the gene in normal looking plants.
"So you've got something that looks like a mutation and behaves like a mutation, but it's actually caused by the packaging of the DNA and not by the DNA sequence itself," Richards said.
The gene affected in the bal variant is involved in disease resistance and is called an R-gene. The research shows that there is a cost of resistance in plants. In the bal plant, the
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Contact: Tony Fitzpatrick
tony_fitzpatrick@aismail.wustl.edu
314-935-5272
Washington University in St. Louis
11-Feb-2002