ORIGINAL ARTICLE

Differential of PAL and PR2 Expressions in Barley Plants Challenged with Seed (Pyrenophora graminea) and Soil-Borne (Cochliobolus sativus) Fungal Pathogens

The seedborne Pyrenophora graminea and the soilborne Cochliobolus sativus are economical fungal pathogens of barley worldwide. To better understand barley mechanisms to resist these two pathogens, expression of two well known defense-related genes PAL and PR2 were monitored in resistant and susceptible barley cultivars at early points of infection using quantitative real-time PCR (qPCR). Data showed significant variance in the expression patterns of both genes between barley P. graminea or C. sativus interactions as compared to the non-inoculated controls. It is also notable that PAL and PR2 genes have a higher expression and faster induction in the resistant cultivar as compared with the susceptible one after infection with each pathogen. However, qPCR analysis revealed higher gene expression in resistant barley plants inoculated with seedborne P. graminea as compared with soilborne C. sativus, with a maximum expression for PAL (15 and 6.8-fold) at 72 hours post inoculation and PR2 (13.2 and 5.3-fold) at 96hpi, respectively. Our data suggest that PAL and PR2 genes, positively regulate P. graminea and C. sativus—resistance in barley plants during disease progress, which can provide useful information for a deeper molecular research on barley defense responses against pathogens with different infection styles.