DEB-9509123 CLAY The proposed research will investigate the advantages gained by a parasite when it manipulates the reproductive system of its host. The fungus, Atkinsonella hypoxylon, infects the grass Danthonia spicata (poverty grass) throughout eastern North America. The parasite prevents its host from mating with other plants and forces it to reproduce only by self-fertilization. The fungus spreads contagiously by spores or by the infection of self-fertilized seeds. The objectives of this research are to test the relative importance of these different mechanisms of fungal reproduction on fungal reproductive success and to determine the genetic changes that result from the parasite's manipulation of host reproduction. The results of this research will reveal how the genetic identity of the host affects its susceptibility to parasitism. This offers great promise in advancing our efforts in agronomy for the development of pest-resistant crops. The mode of parasite transmission is also of great interest because it appears to play a central role in the development of less damaging host/parasite relationships. Many significant human diseases have the same pattern of transmission. By altering the primary mode of transmission of the parasite from contagious spread to transmission to host offspring, it may be possible to reduce the severity of parasite infections in human populations.
