Net blotch and leaf stripe caused by Pyrenophora teres and Pyrenophora graminea, respectively, are economical diseases of barley worldwide. Relatively little is known about the defense responses of barley challenged with these two closely related species. In the current work, 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 the both genes between barley P. teres or P. graminea interactions as compared to the non-inoculated controls. It is also noteworthy that PAL and PR2 genes have a higher constitutive expression and faster induction in the resistant cultivar as compared with the susceptible one after infection with each pathogen. However, PCR (qPCR) analysis revealed higher gene expression in resistant barley plants inoculated with P. graminea as compared with P. teres, with a maximum expression for PR2 (13.8 and 6.41-fold) and PAL (14.8 and 7.89-fold) respectively, at 6 days post inoculation. The obtained results suggest that PAL and PR2 genes, positively regulate P. teres and P. graminea—resistance in barley plants during disease progress, which can provide testable hypotheses that will need direct future tests to determine how these changes may be specified in the genome of these closely related Pyrenophora species.

中文翻译：

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PAL和PR2发病相关基因在受近缘核核菌攻击的大麦植株中的表达

Pyrenophora teres 和 Pyrenophora graminea 分别引起的网斑病和叶斑病是世界范围内大麦的经济病害。关于受到这两种密切相关物种挑战的大麦的防御反应知之甚少。在目前的工作中，使用定量实时 PCR (qPCR) 在感染早期监测抗性和易感大麦品种中两个众所周知的防御相关基因 PAL 和 PR2 的表达。数据显示，与未接种的对照相比，大麦圆球藻或禾谷假单胞菌相互作用之间的两种基因的表达模式存在显着差异。还值得注意的是，与每种病原体感染后的易感品种相比，PAL 和 PR2 基因在抗性品种中具有更高的组成型表达和更快的诱导。然而，PCR (qPCR) 分析显示，与 P. teres 相比，接种了 P. graminea 的抗性大麦植物中的基因表达更高，PR2（13.8 和 6.41 倍）和 PAL（14.8 和 7.89 倍）的最大表达分别为接种后6天。获得的结果表明，PAL 和 PR2 基因在疾病进展过程中对大麦植物的抗性进行正向调节，这可以提供可检验的假设，未来需要直接测试来确定这些变化如何在基因组中指定这些密切相关的 Pyrenophora 物种。