Gene expression in European Ash in response to inoculation with Hymenoscyphus pseudoalbidus

Abstract: European Ash is one of the economically important tree in Europe which is threatened by an invasive pathogen namely Hymenoscyphus pseudoalbidus, causing Ash dieback disease. Our objective was to investigate genes that are expressed after inoculation with this fungus and with freezing injury. In this experiment, high-throughput cDNA sequencing (RNA-seq) data was obtained from Ash bark subjected to different experimental conditions namely control, freezing and inoculation with fungus. RNA-seq data were generated by Illumina sequencing and analyzed by TopHat and Cufflinks. 70083 transcripts were represented in the libraries which all of them belonged to Ash. 97 transcripts were significantly differentially expressed in the control and freezing comparisons, 204 transcripts in the control and inoculation comparison and 151 transcripts in the comparison between freezing and inoculation. It was found that genes responded to abscisic acid (ABA) were up regulated by inoculation. But the expression of ABA 8-hydroxylase genes, which play roles in ABA degradation, was decreased.