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Investigation of the role of Nep1-like protein from Leptosphaeria maculans in planta

Georgia Mitrousia: University of Hertfordshire

<div>Proteins of the superfamily of necrosis and ethylene-inducing peptide 1 (Nep1)-like proteins (NLPs) were examined for their role using the <em>Leptosphaeria</em> <em>maculans</em>-<em>Brassica</em> sp. system. These secreted proteins have been studied in various phytopathogenic microorganisms. They are involved in cell death but also in activation of host innate immune responses. At least one NLP has been identified in <em>L. maculans</em> (Lm_NLP1), the causal agent of phoma stem canker on <em>Brassica</em> plants. A previous study showed that Lm_NLP1 is required for the complete virulence of <em>L. maculans</em> and induces HR-like cell death following transient expression in tobacco leaves. Here, a construct for recombinant expression of Lm_NLP1 was generated and the protein was expressed and purified. The purified protein was infiltrated into host plant leaves (<em>Brassica</em> <em>napus</em>) and its cytotoxic activity was examined. Additionally, it is observed that a 24-residue peptide, which includes Conserved Regions I and II from Lm_NLP1, is recognised in a variety of <em>Arabidopsis</em> and <em>Brassica</em> lines as a PAMP, and induces a transient ROS-burst in a dose-dependent manner. This will enable us to determine the role of Lm_NLP1 protein as a whole, as well as the conserved peptide region, in triggering host responses.</div>