Comparative Proteomics Reveals Set of Oxidative Stress and Thaumatin-Like Proteins Associated with Resistance to Late Blight of Tomato

Abstract

Proteomics techniques were used to study the molecular mechanisms involved in the defense of tomato against late blight (Phytophthora infestans). Proteins were extracted from resistant access BGH-2127 and susceptible cultivar “Santa Clara”. Leaves of the inoculated and non-inoculated (control) genotypes were collected at 0, 2, and 48 h after inoculation and analyzed by two-dimensional electrophoresis (2-DE), followed by identification with mass spectrometry (MALDI TOF-TOF). A total of 56 differentially abundant proteins were identified, of which 39 were resistant genotypes and 17 were susceptible. These proteins were categorized into functional groups of energy and metabolism, photosynthesis, stress and defense, transcription, other proteins, and as un-characterized ones. For access BGH-2127, oxidative stress proteins (2-cis peroxiedoxin BAS1 and 2-cis peroxiredoxin) and thaumatin-like protein showed increase in the relative abundance at 0 and 48 h of inoculation, respectively, and were therefore considered important for the defense mechanism of this genotype. The expression standards evaluated by real-time PCR differed from the results of the proteomic analysis. The protein-protein interaction networks provided important information on the cellular activities involved in the resistance of BGH-2127 late blight.