Bacterial diseases cause significant losses in many crops, and control
measures are often limited or unavailable. The majority arise from
invasion of the vascular system or colonization of the leaf parenchyma.
The major classes of molecular tools that enable bacteria to thrive
inside plants are beginning to be understood, but little is known
about the functions within the plant of most of these tools. Less
still is known about the plant signals and targets that render plants
susceptible. Virtually nothing is known of the basis for tissue specificity.
An understanding of the pathogen and host traits that create opportunities
for microbes to exploit different plant tissues is an important goal.
It will advance our fundamental understanding of plant biology and
support innovative efforts to develop strategies to alter plant susceptibility
or block pathogen virulence.
This five-year functional genomics project will identify plant genes
that affect susceptibility or tissue specificity to two closely related
pathogens of the same host that cause different types of disease,
one vascular and the other parenchymal. The project will characterize
genetic differences between these pathogens, and identify plant genes
differentially expressed in response to them. Rice (Oryza sativa),
an important crop and a model species, will be used for these studies.
Bacterial leaf blight (vascular) and bacterial leaf streak (parenchymal)
will be examined. These diseases are caused by the two subspecies
of Xanthomonas oryzae, pathovar oryzae and pathovar oryzicola,
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designed by L. Darnielle and is maintained by K.
September 7, 2005