goal of my research is to understand the genetic bases of plant
host-pathogen interactions, at both the molecular and population levels.
This information will be used to increase the level of resistance in
cereal crops to foliar diseases caused by fungi.
Septoria disease of wheat, caused by the two fungi Mycosphaerella graminicola (anamorph Septoria tritici) and Phaeosphaeria (Septoria) nodorum,
is an economically important disease that occurs throughout the world.
Analyses of the population genetics of these pathogens in Indiana are
being conducted to reveal the primary sources of inoculum, the extent of
gene flow among populations and the modes of reproduction during
epidemics. Methods for genetic analyses of P. nodorum have been
developed recently and are being applied to elucidate the genetic basis
of pathogenicity. The number of genes involved in pathogenicity and
their mode of action are still not known. Molecular markers (including
RFLP, RAPD, AFLP and microsatellite technologies) are being used to
develop genetic maps and identify the chromosomal locations for
pathogenicity genes and other traits of biological interest. Another
aspect of my research is to use phylogenetic analyses to determine the
evolutionary relationships among both septoria pathogens and their
nearest relatives. Understanding the mechanisms of speciation in
pathogenic fungi could indicate new approaches for developing improved
disease management strategies.
Work with the host
is focused on identifying genes for resistance in wheat, and on finding
molecular markers that are closely linked to resistance genes. Molecular
markers that tag known resistance genes will be used to facilitate the
incorporation of resistance into wheat through plant breeding programs.
Genetic analyses of resistance and of molecular markers will aid the
eventual cloning and molecular characterization of plant genes for
resistance to foliar fungal pathogens.