title: Proteome Biomarkers in Xylem Reveal Pierce's Disease Tolerance in Grape.
abstract: Pierce's disease (PD) is a significant threat to grape cultivation and industry. The disease caused by bacteriumXylella fastidiosaclogs xylem vessels resulting in wilting of the plant. PD-tolerant grape genotypes are believed to produce certain novel components in xylem tissue that help them to combat invading pathogens. Research has been aimed at characterizing the uniquely expressed xylem proteins by PD-tolerant genotypes. The objectives were to i) compare and characterizeVitisxylem proteins differentially expressed in PD-tolerant and PD-susceptible cultivars and, ii) identify xylem proteins uniquely expressed in PD-tolerant genotypes. A high throughput two-dimensional gel electrophoresis of xylem proteins from threeVitisspecies identified more than 200 proteins with pls 3.0 to 9.0 and molecular weights of 20 to 75 kDa. The differentially expressed proteins were then excised and analyzed with MALDI/TOF mass spectrometer. The mass spectra were collected and protein identification was performed against theViridiplantaedatabase using Matrix Science algorithm. Proteins were mapped to the universal protein resource to study gene ontology. Comparative analysis of the xylem proteome of three species indicated the highest number of proteins in muscadine grape, followed by Florida hybrid bunch and bunch grape. These proteins were all associated with disease resistance, energy metabolism, protein processing and degradation, biosynthesis, stress related functions, cell wall biogenesis, signal transduction, and ROS detoxification. Furthermore, β-1, 3-glucanase, 10-deacetyl baccatin III-10-O-acetyl transferase-like, COP9, and aspartyl protease nepenthesin precursor proteins were found to be uniquely expressed in PD-tolerant muscadine grape, while they are absent in PD-susceptible bunch grape. Data suggests that muscadine and Florida hybrid bunch grapes express novel proteins in xylem to overcome pathogen attack while bunch grape lacks this capability, making them susceptible to PD.
authors.forename: Ramesh
authors.initials: R
authors.lastname: Katam
authors.forename: Kundai
authors.initials: K
authors.lastname: Chibanguza
authors.forename: Lekan M
authors.initials: LM
authors.lastname: Latinwo
authors.forename: Danyel
authors.initials: D
authors.lastname: Smith
keywords: Pathogenesis-related proteins; Pierce’s disease; Proteome; Vitis spp; Xylem