1a.Objectives (from AD-416):
Objective 1: Identify genes involved in pathogenicity/virulence of Phytophthora infestans and Streptomyces scabies.
Objective 2: Identify variations in genome sequences that distinguish isolates of Phytophthora infestans and Streptomyces scabies.
Objective 3: Develop transgenic potato and tomato plants for functional genomics and disease resistance application.
1b.Approach (from AD-416):
Characterization of pathogen isolates will be followed by defined, reproducible studies on interactions with a specific host using these isolates. Genes potentially involved in pathogenicity for each pathogen will be sought using a bioinformatics approach to select and screen candidate genes from the respective genome databases for each pathogen. Testing these genes will be carried out using methods of over-expression and suppression. Multiple databases of genetic information available for Solanaceous crop plants (potato, tomato, eggplant, pepper) will be used to help select genes that may be involved in limiting disease caused by Phytophthora and Streptomyces. Once candidate genes are identified, their role in limiting disease will be determined. Simultaneous studies of pathogen and host will provide new information and tools to be used in breeding and engineered control strategies to limit these major diseases of potato and tomato.
A newly identified gene cluster from potato was determined to harbor three unique copies of a xyloglucan-specific endoglucanase inhibitor protein gene. They are unique in that they do not contain the standard signal sequence for protein export from the cell, suggesting either an alternate secretion pathway, or a yet unidentified role for these proteins within the plant cell.