EVALUATION OF SOME DEFENSIN GENES AGAINST ToMV IN DIFFERENT TOMATO CULTIVARS USING PATHOGENESIS RELATED PROTEIN GENES

Abstract

The tomato (Solanum lycopersicum) is considered as one of the most important commercially grown vegetables which cultivated through the whole year. From several issues that may face the tomato breeders worldwide are susceptible to many viruses which cause yield losses and reduction in product quality. The goal of this work is to detect and determine some of the defense genes against viral infection diseases in different tomato cultivars infected with tomato mosaic virus (ToMV) by using two molecular techniques: differential display polymerase chain reaction (DD-PCR) and quantitative real time polymerase chain reaction (qRT-PCR) using pathogen related proteins (PRs) to identify and measure expression of pathogen related genes of ToMV. The obtained results have shown differentially expressed banding patterns due to viral infection and variable gene intensities were observed. There were 4 different bands selected randomly, purified and sequenced, the sequence analysis those bands revealed three up-regulated genes (putative permease gene; pathogenesis-related genes transcriptional activator PTI6 gene and linoleate 13S-lipoxygenase 3-1, chloroplast gene), and one down-regulated gene is endochitinase gene. We concluded that the role of the pathogenesis related genes either induced or suppressed during interaction between tomato plant and ToMV but also, the endogluconase (PR1) and chitin binding protein (PR4) expression increased during pathogen infection by ToMV, while the expression of chitinase (PR3) decreased/inhibited during infection by ToMV.