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BackgroundBarley leaf stripe disease, caused by the fungus Pyrenophora graminea (Pg), is a worldwide crop disease that results in significant loss of barley yield. The purpose of the present work was to use transcriptomic profiling to highlight barley genes and metabolic pathways affected or altered in response to Pg infection and consequently elucidate their involvement and contribution in resistance to leaf stripe.ResultsOur study examined and compared the transcriptomes of two barley genotypes using an established differential display reverse-transcription polymerase chain reaction (DDRT-PCR) strategy at 14 and 20 days post-inoculation (dpi). A total of 54 significantly modulated expressed sequence tags (ESTs) were identified. The analysis of gene expression changes during the course of infection with Pg suggested the involvement of 15 upregulated genes during the immunity response. By using network-based analyses, we could establish a significant correlation between genes expressed in response to Pg invasion. Microscopic analysis and quantitative PCR (qPCR) profiling of callose synthase and cellulose synthases revealed a direct involvement of cell wall reinforcement and callose deposition in the Pg-resistant phenotype.ConclusionsWe have identified a number of candidate genes possibly involved in the host-pathogen interactions between barley and Pg fungus, 15 of which are specifically expressed in Pg-resistant plants. Collectively, our results suggest that the resistance to leaf stripe in barley proceeds through callose deposition and different oxidation processes.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-016-2573-x) contains supplementary material, which is available to authorized users.

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The European corn borer moth, (ECB), Ostrinia nubilalis (Lepidoptera: Crambidae, Pyraustinae) is one of the most destructive pests of maize worldwide. ECB has two pheromone-strains, separated by specific ratios of isomers of E-and Z11-tetradecenyl acetates (E11-and Z11-14Ac), but appearing morphologically identical. Accordingly, E-and Z-ECB pheromone traps are available for the respective populations for practical monitoring of the flight, however, traps for Z-strain are unreliable for practical usage in some parts of Central-Europe. E-and Z-ECB populations occur in sympatry in some areas, while in allelopatry in other areas. Determining the strains before the flight of adults, when difference in the composition of their respective pheromones is manifested, would be of practical interest for early warning. In addition to the known fatty-acyl-reductase (FAR) marker, further markers would allow more comprehensive studies. We screened the following common markers for mitochondrial and nuclear DNA regions: partial cytochrome c oxidase I (COI), cytochrome B (CytB), the second spacer of the internal transcribed spacer (ITS2), Elongation factor 1a (EF1a) and actin gene (Act). In addition, a marker of the Δ11-desaturase gene (11desat), linked to biosynthesis of female-produced sex pheromone, was also included, because we reported earlier a differential expression for this site. Three Z-ECB populations locating at distant sites within Hungary, an area where only Z-strain occurs, and an E-ECB population in Slovenia, known as the closest-occurring E-strain, were included into the study. Separate laboratory colonies were established from each population, and F 1 generations were sampled to verify the identity of pheromone strains, by analysing the composition of sex pheromone by gas chromatography linked to an electroantennographic detector (GC-EAD). Molecular studies were conducted using specimens taken from the F 2 generations. Results of genetic studies showed that there were no differences between the Z and E populations for the common markers. In contrast to this, several nucleic acid changes (11 nt in 4 positions) were found between the three Z-populations (Hungary) and the E-population (Slovenia) in the desaturase marker. Further study is required to reveal whether the differences found in this study are consistent across E-populations, thus making these markers suitable for diagnostic purposes.

The seed-borne (Pyrenophora graminea; Pg) and foliar (Blumeria graminis; Bg) are two economically important fungal pathogens of barley worldwide. Barley plant resistance genes, as the pathogenesis related proteins play an important role in defense mechanisms. This study aimed to monitor the expression of PR2 and PAL pathogenesis related genes during compatible/incompatible barley interaction with Pg and Bg at different time points of disease development using the Quantitative Real-time PCR technique (qRT-PCR). Comparison of data showed that PR2 and PAL were significantly over expressed in infected resistant and susceptible plants as against their lower expression in controls,. Upregulation of these defense-related genes during Pg and Bg infections was companied with a slow development of disease symptoms at the time course in the resistant genotype. qRT-PCR analysis revealed higher gene expression in resistant barley plants inoculated with Pg as compared with Bg, with a maximum expression for PR2 (13.8 and 5.06-fold) and PAL (14.8 and 4.51-fold) respectively, at the latest stage of each disease development. It was also noteworthy that PR2 and PAL genes, had higher constitutive expression and faster induction for the both pathogens in the resistant genotype as compared with the susceptible one. Obtained results suggest that both genes, PR2 and PAL, positively regulate Pg- and Bg-resistance in barley plants during disease progress. These expression patterns can provide useful insights to better understanding of the barley–fungus interactions with different fungal lifestyles.