Vasanthaiah, Hemanth KN , Katam, Ramesh , Basha, Sheikh M .
Application of Functional Genomics Approach to Analyze Pierce’s Disease in Grapes.
Pierce’s Disease (PD) is a devastating disease of bunch grape (Vitis vinifera) which has proven to be major factor responsible for degeneration of grapevines in Southeastern United States. For the first time identification of specific transcripts expressed differentially in xylem tissue of bunch and Florida bunch hybrid genotypes upon challenging with xylem limited Xylella fastidiosa (which causes PD) was carried out to understand the basis of PD-tolerance. Differential display RT-PCR and PCR based subtractive hybridization were employed to identify uniquely and differentially expressed transcripts induced upon infestation. Both techniques complimented each other in isolating both abundant and weakly expressed transcripts. The plants were inoculated with virulent strains of Xylella, and xylem tissue was collected at regular intervals. DDRT-PCR results revealed significant up-regulation of several cDNA transcripts in tolerant genotype compared to susceptible/less susceptible genotype studied. Certain transcripts were consistently expressed in uninfected and infected xylem tissue of PD-tolerant genotype but were absent in susceptible cultivar studied. Subtractive hybridization also yielded several partial cDNAs uniquely expressed in moderately tolerant V. Vinifera cv. Zinfandel and in tolerant Florida bunch hybrid (Blanc du Bois) genotype. Expression of transcriptional factor, enolase, adenosine kinase, elongation factor alpha gene, quinone reductase, ribosomal RNA genes, translationally controlled tumor protein etc., in tolerant genotypes showed their adaptation mechanism for pathogen infestation. Several other genes were uniquely expressed in tolerant genotypes and have been deposited in NCBI database. The expressions of these genes were confirmed through real time PCR. The data suggests that Xylella infection affects cDNA transcript/s expression more significantly in PD-susceptible genotypes compared to the PD-tolerant cultivars. Further, full-length gene/s responsible for PD tolerance will be derived for its possible incorporation into commercially important grape cultivars.
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1 - Florida A & M University, Division of Plant Biotechnology, Center for Viticulture and Small Fruit Research, 6505 Mahan Drive, Tallahassee, Florida, 32317, USA
2 - Florida A & M University, Division of Plant Biotechnology
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM