Submitted to: Plant and Animal Genome VX Conference Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 1/12/2005
Publication Date: 1/5/2006
Citation: Borrone, J.W., Meerow, A.W., Kuhn, D.N., Schnell Ii, R.J. 2006. Potential phylogenetic utility of WRKY gene family members. Plant and Animal Genome VX Conference Abstracts. Interpretive Summary: Single or low-copy nuclear genes are ideal data to determine the evoltionary relationships of species because they evolve faster than chloroplast or mitochondrial genes. WRKY genes are transcriptional factors that regulate ancient plant pathways. They contain highly conserved regions, and more variable regions, would make them useful for determining evolutionary relationships. Members of the WRKY family of transcriptional factors were assayed for their potential to determine the evolutionary relationships of Theobroma and Herrania. Five WRKY genes performed well with resolving the evolutionary relationships. The ease of isolation and informativeness should make them useful for determining the evolutionary relationships of plant species.
Technical Abstract: Single and low copy nuclear genes represent a source of multiple, unlinked and independently-evolving loci, the ideal data set for molecular phylogenetic inference due to their high rate of synonymous substitution compared to chloroplast or mitochondrial genes. The WRKY gene family of transcription factors regulates several diverse, ancient, and highly conserved plant-specific networks including plant defense responses to biotic and abiotic stress; seed, embryo, and trichome development; and regulation of sesquiterpene, starch, and anthocyanin anabolsm. WRKY proteins contain highly conserved domains. The coding region of the highly conserved functional DNA binding domain is commonly interrupted by an intron. Partial sequences of several WRKY loci, originally isolated from Theobroma cacao with a single pair of degenerate primers, were assessed for their phylogenetic utility. Primers designed specifically to amplify individual T. cacao WRKY loci were tested across the sister genera Herrania and Theobroma with Guazuma ulmifolia as the outgroup. The combined WRKY matrices performed as well or better than other genes in resolving the intrageneric phylogeny of Herrania and Theobroma. The ease of isolating numerous, independent WRKY loci with degenerate primers, combined with amplification using primers specific for each locus, renders the WRKY gene family as extremely useful for generating multiple, single- or low-copy nuclear loci for molecular phylogenetic studies at lower taxonomic levels.