RESUMEN
Late blight is one of the most destructive diseases of the tomato, resulting in substantial economic losses. There is difficulty in controlling this disease, so the molecular characterization of tomato genotypes may help in the selection of higher resistance tomato plants against Phytophthora infestans, late blight's pathogen. The objective was to analyze the differences with regard to the constitutive proteome between the access Vegetable Germplasm Bank (BGH)-2127, resistant genotype, and Santa Clara-susceptible genotype to late blight. Proteomic analysis of leaf samples by two-dimensional electrophoresis (2-DE) followed by identification by mass spectrometry (MALDI TOF/TOF) was performed. Nineteen proteins were identified, which were then related to metabolism and energy, photosynthesis, transcription, stress, and defenses. Approximately 90% of these proteins were more abundant in Santa Clara, a susceptible cultivar. Acidic 26 kDa endochitinase and ribonuclease T2 proteins were more abundant in BGH-2127 access. The enzymatic activity confirmed a greater abundance of chitinase in the BGH-2127 access as compared to the cultivar Santa Clara. Gene expression analyses by real-time PCR demonstrated that the mRNA levels were not correlated with the respective protein levels. Abundance of the acidic 26 kDa endochitinase and ribonuclease T2 proteins in the constitutive proteomes of BGH-2127 may be associated with the answer to the resistance of this access.