Characterization of the molecular mechanisms for induction of fungal defense in response to challenge with antagonists
The regulation of the biosynthesis of fungal defense effector molecules (toxins) in fungi is poorly understood. Preliminary evidence by our and other laboratories suggests that fungal defense effector molecules can be produced either constitutively under axenic conditions in a tissue-specific manner, or be induced in response to challenge with antagonists. Interestingly, induction of fungal defense effector genes appears to be antagonist-specific indicating that fungi are, similar to plants and animals, capable of recognizing the antagonist and mount a respective defense response.
In case of the specific defense response of C. cinerea to B. subtilis and E. coli, we recently found that supernatants of axenic cultures of these bacteria are sufficient for induction (Stöckli et al 2019 DOI: 10.1111/mmi.14277). Current experiments aim at the isolation and identification of the bacterial inducer of this defense response from bacterial culture supernatants.
In case of the specific defense response of C. cinerea to A. avenae, we found that this response is propagated within the mycelium along specific hyphae suggesting a systemic response similar to plants (Schmieder et al 2019 DOI: 10.1016/j.cub.2018.11.058). Current experiments aim at the dissection of the molecular basis of the induction (nematode signals and fungal receptors) and propagation of this defense response within the mycelium.