Submitted on April 8, 2008
Revised on July 31, 2008
Accepted on August 27, 2008
Quantitative proteomic analysis of bean plants infected by a virulent and avirulent obligate rust fungus
Joohyun Lee, Jian Feng, Kimberly B. Campbell, Brian E. Scheffler, Wesley M. Garrett, Sandra Thibivilliers, Gary Stacey, Daniel Q. Naiman, Mark L. Tucker, M. A. Pastor-Corrales, and Bret Cooper
Soybean Genomics and Improvement Laboratory, USDA-ARS, Beltsville, MD 20705
Corresponding Author: bret.cooper{at}ars.usda.gov
Plants appear to have two types of active defenses, a broad-spectrum basal system and a system controlled by R-genes providing stronger resistance to some pathogens that break the basal defense. However, it is unknown if the systems are separate entities. Therefore, we analyzed proteins from leaves of the dry bean crop plant Phaseolus vulgaris using a high-throughput liquid chromatography tandem mass spectrometry method. By statistically comparing the amounts of proteins detected in a single plant variety that is susceptible or resistant to infection, depending on the strains of a rust fungus introduced, we defined basal and R-gene mediated plant defenses at the proteomic level. The data reveal that some basal defense proteins are potential regulators of a strong defense weakened by the fungus and that the R-gene modulates proteins similar to those in the basal system. The results satisfy a new model whereby R-genes are part of the basal system and repair disabled defenses to reinstate strong resistance.