Project Number: 5302-22000-008-20
Project Type: Specific Cooperative Agreement

Start Date: Aug 30, 2004
End Date: Jul 31, 2009

Objective:
Identify (1) PD resistant gene(s) and gene products in grapes, and identify metabolic pathways involving mechanisms of pathogenesis and resistance; (2) Identify pathogen genotypes; (3) Determine the pathotype-host interactions; and (4) Genetic analyses Xf diversity and population structures of Xf in California almond orchards/vineyards, insects and potential reservoir hosts.

Approach:
Highly susceptible and resistant genotypes selected from the segregated population of V. rupestris x V. arizonica hybrid population will be used for parallel PD expression study. Differentially expressed genes in response to the Xylella fastidiosa infection will be cloned by constructing Subtractive Suppression Hypridization cDNA libraries and sequenced. Bioinformatic data analyses will be performed to annotate sequence data of expressed genes and to identify biological functions of these genes associated with resistant/susceptible to the Xylella fastidiosa. Putative genes will be further analyzed using microarray gene expression techniques. Genes and gene products underlying metabolic pathways leading to disease development or disease resistance will be determined. Proteomic profiles related to grape responses to Xf infection will be determined. Xylella pathotypes will be identified using DNA markers and pathotype-associated host expression patterns will be determined. Develop multiplex SSR and SNP DNA markers for genotyping Xf. Perform hierarchical genetic structure analyses among populations. Construct allele frequency database in Xf populations; analyze spartial temporal population dynamics associated with occurrence and severity of PD and ALSD. Information will be used to develop novel molecular strategies to improve grape resistance to PD. Transcriptional profiles developed will be incorporated into a comprehensive database and will be available to the public.Formerly 5302-22000-007-07S (5/07).