Streptomyces scabies is a gram positive soil bacterium that is the causative organism for scab disease on a variety of underground vegetables. The scab lesion that forms at the site of infection is composed of a proliferation of suberinized material by the plant. The mechanism by which the organism elicits the formation of the typical scab lesion on the tuber is not well understood, but may involve the production of compounds such as thaxtomin by the pathogen. The goal of this proposal is to begin to study the regulation of expression of plant genes, in response to the infection process. In order to identify these plant regulated genes, a cDNA library will be prepared from tissue with developing scab lesions. Differential hybridization of the library with cDNAs prepared from non-scab plant tissue versus cDNAs prepared from scab tissue will be used to identify genes expressed specifically during lesion formation. Future work will be focused on studying the regulation of the genes and on the identification of the gene products that are made in response to infection.
