Conserved Microsynteny of NPR1 with Genes Encoding a Signal Calmodulin-Binding Protein and a CK1-Class Protein Kinase in Beta vulgaris and Two Other Eudicots

NPR1 is a gene of central importance in enabling plants to resist microbial attack. Therefore, knowledge of nearby genes is important for genome analysis and possibly for improving disease resistance. In this study, systematic DNA sequence analysis, gene annotation, and protein BLASTs were performed to determine genes near the NPR1 gene in Beta vulgaris L., Medicago truncatula Gaertn, and Populus trichocarpa Torr. & Gray, and to access predicted function. Microsynteny was discovered for NPR1 with genes CaMP, encoding a chloroplast-targeted signal calmodulin-binding protein, and CK1PK, a CK1-class protein kinase. Conserved microsynteny of NPR1, CaMP, and CK1PK in three diverse species of eudicots suggests maintenance during evolution by positive selection for close proximity. Perhaps close physical linkage contributes to coordinated expression of these particular genes that may control critically important processes including nuclear events and signal transduction.