Abstract
The fungi Zymoseptoria tritici (former Mycosphaerella graminicola) is a hemibiotrophic wheat pathogen and contains accessory chromosomes (AC). These ACs remain in the population despite no positive effect for the organism. The role of the origins of replication (ORI) in this context is unknown. To compare ORIs of ACs and core chromosomes, we meant to create two mutant strains of Z. tritici, which had tagged sequences of two ORI associated proteins via Agrobacterium mediated transformation (ATM). Although we transformed A. tumefaciens successfully, it was not able to find a positive transformed Z. tritici. This probably has to do with a dysfunctional mitosis caused by the tagged sequences of two essential proteins.
Effector proteins play an important role for Z. tritici during the infection of wheat. These effector proteins are classified in biotrophic and necrotrophic effectors. Many effector proteins are unknown today. In this second part of the project, we analysed the biotrophic effector candidate encoding gene Zt09_chr_3_00467 by in planta and in an in vitro stress assay. We were able to show indications that Zt09_chr_3_00467 is not encoding for a biotrophic effector. Only one deletion mutant out of three showed a significantly lower virulence compared to the reference strain IPO323. But our results also indicated that these deletion mutants were not as highly genetically similar as expected. This work provides a first important step in characterising Zt09_chr_3_00467. Nevertheless, further experiments are necessary in order to prove our indications.
