Transcriptome sequencing at early stage infection of the wheat pathogen Zymoseptoria tritici reveals chromosomal differences in transcription patterns and host specific gene expression.. Zymoseptoria tritici

We have applied whole transcriptome profiling to infer genetic determinants of pathogenicity and host specialization in Z. tritici. Our data includes RNAseq data from early infection stages of a compatible (wheat) and a non-compatible host (Brachypodium distachyon). Overall transcription of AC genes is remarkably lower than genes on core chromosomes (CC) and only 40% of the genes are transcribed. We identify 31 AC and 1069 CC genes showing plant specific expression. In addition 21 CC genes are only upregulated in wheat supporting functional relevance in host specificity. We further explore the genomic composition and distribution of unique and paralogous genes in Z. tritici focusing on the evolutionary origin of AC genes. In contrast to previous studies we show that ACs mainly encode unique genes. Phylogenetic analyses suggest that rare duplication events in the Z. tritici genome precede diversification of Zymoseptoria species and demonstrate that ACs have been maintained in the genome of Zymoseptoria over long evolutionary times. Overall design: Examination of gene expression at 3 different growth condition of the wheat pathogen Z. tritici.