Bridging Classical and Molecular Genetics of Cotton Disease Resistance

Understanding the series of events that causes a symptomatic disease response brings to light the relationship between a pathogen and its host. More than 50 bacteria, fungi, virus, and nematodes have been implicated in cotton diseases that annually account for an estimated $897 million in lost revenue to the U.S. crop. Advances in cotton genetics have led to the development of several technologies that enable the detailed examination of the cotton genome for genes that function in response to pathogen infection. There is an opportunity to make direct and meaningful comparisons from data generated by forward and reverse genetics. Comparing QTL information with reverse genetics (functional genomics) offers a powerful approach to identify and characterize the key pathways and the genetics involved in disease. Cotton is an interesting taxon in which to study disease because its evolution includes the divergence of resistance (R-genes) through the radiation of species, as well as multiple genetic bottlenecks including polyploid formation and the domestication of a small subset of Gossypium species.