International Symposium on Cereal Leaf Blights 2019 | University College Dublin, Ireland | 22-24 May 2019

Divergence of aggressiveness of Zymoseptoria tritici isolates on a susceptible wheat cultivar revealed by comparative genomics

Heshasm Gibriel*

Poster Presentation
Evolution and Population Biology

Atrium, UCD O'Brien centre for Science
Poster 3

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Zymoseptoria tritici is a fungal wheat pathogen that causes Septoria tritici leaf blotch (STB), which is considered the most damaging disease of wheat in Europe. Phenotyping of multiple Z. tritici isolates on the wheat cultivar Longbow revealed divergence in aggressiveness on this particular wheat cultivar. This divergence in aggressiveness may be explained by large scale structural variations (presence or absence of chromosomes) or modifications at the nucleotide level within genes that encode for secreted proteins, so called effectors. Here, we aimed to determine the differential aggressiveness of these Z. tritici isolates on the wheat cultivar Longbow using comparative genomics and transcriptomics, while focusing on effector genes. Of all the phenotyped isolates, we observed that Z. tritici isolates, namely 553.11, S-Oak, and S-Cork were the most aggressive on wheat cultivar Longbow, whereas the remaining seven isolates showed moderate or reduced aggressiveness on this wheat cultivar. Comparative transcriptomics analysis revealed one effector gene that is significantly differentially expressed in the highly aggressive Z. tritici isolate 553.11 in comparison to the moderately aggressive Z. tritici isolates IPO323 and 560.11. Future functional analysis will be performed to confirm the contribution of this candidate effector gene to Z. tritici aggressiveness. Here, we determined genome-wide differences in a collection of Z. tritici isolates that have the differential capacity to infect the susceptible wheat cultivar Longbow, which will provide insights into Z. tritici aggressiveness.