Scientists Identify Grasses' Guardian Gene

Scientists from the US Agricultural Research Service and Purdue University have identified a gene in maize that provides resistance against Cochliobolus carbonum race 1 (CCR1), the pathogen that causes the destructive maize leaf blight, root and stalk rot and ear mold. The resistance gene, Hm1, was discovered by studying maize mutants. Interestingly, the group discovered that Hm1 is also present in other grass species like sorghum, rice, barley, wheat and millet.

The particular position of Hm1 in the genome, coupled with the maintenance of its function through numerous generations, suggests that the gene may have played a critical role in the evolution of grass species. It is very likely that CCR1 or its ancestral form, given its devastating potential, would have threatened the existence of grass species or at least limit their distribution, had Hm1 not evolved to counteract the toxins produced by the pathogen.

Further studies are being conducted to understand the mechanisms underlying Hm1 mediated resistance. The discovery of a gene capable of providing pathogen protection to a taxonomic group may prove to be important for scientists seeking to develop similar resistance in other crop groups.

Read the press release at http://www.ars.usda.gov/News/docs.htm?docid=1261 The abstract of the paper published by PNAS is available at http://www.ars.usda.gov/is/pr/2008/080129.htm