Comparative Sequence and Functional Analysis of Stilbene Synthase Genes among Vitis Species

• Author(s): Huang, Wensheng; Hunter, Wayne; Lu, Jiang;
• Abstract: Pierce disease (PD), anthracnose and downy mildew are the limiting factors in the production of European grapes (V. vinifera) in the southeastern United States, especially in Florida where annual precipitation is high. Native American grape species such as V. shuttleworthii, V. aestivalis and V. rotundifolia have evolved strong resistance to these diseases. In order to understand the genetic variation and expression of stilbene synthase, StSy, a phytoalexin, in grape species/varieties and their correlation to disease resistance, 32 sequences of the StSy among grape Vitis species were compared and analyzed. The StSy transcripts from V. shuttleworthii were also analyzed by BLAST comparison against 260 known StSy genes from plants retrieved from NCBI; this list included StSy identified as either full-length or partial sequences. Two V. shuttleworthii, StSy transcripts were represented in low abundance in both V. vinifera and V. shuttleworthii cDNA libraries. Interestingly, one of the StSy contigs was found to have significantly higher transcriptional, expressed sequence tag (EST) abundance in the V. shuttleworthii library while being less represented in the V. vinifera libraries. While differences may be in part to variation in library construction or plant biology when samples were taken examine the differential StSy expression of these three transcripts during challenge by disease pathogens there appeared to be a correlation. Homologous relationships among the StSy multigene family were analyzed by multiple alignments of protein sequences (BLASTP and PAUP). Single nucleotide polymorphism (SNP) sites in the coding region were discovered within the multigene family. Amino acid analyses showed that some of the single nucleotide substitution resulted in amino acid changes. Correlations between single nucleotide substitutions /amino acid changes and disease resistant phenotypes were identified. Analysis of the cSNPs among the StSy appears to be a useful approach for identification of disease resistance in grape phenotypes and is being further evaluated for application to screen current and newly selected grape cultivars for increased disease resistance.
• Publication Date: Jan 2006
• Journal: Acta Horticulturae