Submitted to: Plant Molecular Biology Reporter
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/20/2012
Publication Date: 2/16/2012
Publication URL: http://handle.nal.usda.gov/10113/61499
Citation: Jones, R.W. 2012. Multiple copies of genes encoding XEGIPs and EDGPs are harbored in an 85kB region of potato genome(Solanum tuberosum). Plant Molecular Biology Reporter. 30:1040-1046. Interpretive Summary: Plants have many different ways to defend themselves from becoming diseased. The organism causing the disease continually comes up with new ways to attack the plant, while the plant adds new ways to protect itself, resulting in a continual expansion of defense and attack measures. A new set of plant defensive measures has been identified that counters a set of previously reported measures found in the attacking microbe Phytophthora infestans. This information will be useful to plant breeders and other scientists that are developing disease resistant plants that don’t require chemical control applications for disease control.
Technical Abstract: The XEGIPs (xyloglucan-specific endoglucanase inhibitor protein) and their closest homologues, the EDGPs (extracellular dermal glycoproteins) have been reported in a limited number of plants, principally Solanaceous ones. One function of XEGIP is limiting pathogen attack by interfering with family 12 endoglucanases. The XEGIP gene from tomato and potato was believed to be a single copy, however a cluster of nine similar genes has been found on a single region of potato chromosome, independent of the single XEGIP previously reported. Tomato has a similar number, while pepper, eggplant, nightshade and tamarillo are lacking most of these nine genes. Each plant species was found to have a copy of the originally reported XEGIP. Expression patterns show differences in tissue type, with three of the XEGIP-like genes highly expressed in leaf tissue, and one of the EDGP-like genes highly expressed in potato cell culture. Differential expression was also seen in potato tubers, and tomato fruits. The large number of XEGIP/EDGP encoding genes in potato suggests a selection pressure for defense against the multiple copy family 12 endoglucanase-encoding genes found in the potato pathogen, Phytophthora infestans.