Poster: Plant-pathogen interactions

Abs # 558: Characterizing the grape transcriptome: identification of transcripts correlated with berry development and host responses to Pierce’s Disease of Grapes

Presenter:	Goes da Silva, Francisco D, fdgoesdasilva@ucdavis.edu
Authors	Goes da Silva, Francisco D (A) (D)  Iandolino, Alberto  (B) (D)  Lim, Hyunju  (A) (D)  Choi, Hongkyu  (A) (D)  Baek, Jongmin  (C) (D)  Leslie, Anna  (C) (D)  Xu, Jane  (A) (D)  Cook, Doug  (A) (D)
Affiliations:	(A): Department of Plant Pathology (B): Department of Viticulture and Enology (C): CA&ES Genomics Facility (D): University of California, Davis
Web Site:	http://medicago.ucdavis.edu/

The unique properties of grapes (Vitis spp.) are controlled in part by differential gene expression in response to intrinsic and external cues (e.g., development and biotic/abiotic stresses). We analyzed 145,000 grape nucleotide sequences [i.e., Expressed Sequence Tags (ESTs), genomic sequences and expressed transcripts] derived from 64 cDNA libraries to identify molecular phenotypes correlated with berry development or resistance and susceptibility to the Pierce’s Disease (PD) bacterial pathogen Xylella fastidiosa. After contig assembly and sequence annotation (database available at http://cgf.ucdavis.edu) EST frequencies per contig were used to estimate tissue, developmental stage or treatment specific expression levels. Shared trends in expression profiles among libraries and contigs were first identified by correlation analysis. Two dimensional relationships among contigs and libraries were determined by cluster and principal component analysis. This digital analysis of gene expression is a powerful tool that allows the identification of gene sets specific to different organs and networks as well as reponses to X. fastidiosa for further analyses. The X. fastidiosa responsive feature of several genes identified by this method were further confirmed using real-time reverse transcriptase PCR. The data also facilitates putative functional assigments for anonymous genes based on their common expression with that of annotated genes. We expect that the information generated in this study should complement future transcriptional profilling studies in grapes using DNA microarrays.