Differentially expressed gene transcripts in wheat and barley leaves upon leaf spot infection

A cDNA library was created on the basis of transcripts that were generated during the process of infection of wheat and barley with Pyrenophora tritici-repentis or P. teres. Due to the time course of infection assays, the leaves were collected at various intervals after inoculation until 100 h after inoculation. We compared the temporal development of the two pathogens, as well as the effect of varieties of the same crop species, and differences among isolates of a single pathogen. The appressoria and vesicular structures developed more rapidly in barley varieties inoculated by P. teres than in wheat varieties inoculated by P. tritici-repentis. The lower level of susceptibility of the wheat variety Globus and the barley variety Heris to P. tritici-repentis and P. teres, respectively, was apparent from 12 h after infection. Information on changes in expression profiles during pathogenesis and on the clones that could be functionally assigned to the known gene sequences is presented. Out of the 360 transcript derived fragments (TDFs) produced in the barley-P. teres pathosystem in our trials, 62% were specific to the plant-pathogen interaction. In the wheat-P. tritici-repentis pathosystem 291 TDFs occurred, 63% were specific to the plant-pathogen interaction.