Plant infections caused by fungal plant pathogens such as Fusarium graminearum, Botrytis cinerea, and Rhizoctonia solani lead to significant agricultural losses each year, posing a threat to global food security. A common method to combat these pathogens involves the use of chemical fungicides and pesticides, which often have harmful effects on the environment. A more sustainable alternative is the use of biocontrol agents, such as the fungus Clonostachys rosea. This master’s thesis work investigated two cellobiose dehydrogenases (CDHs) from C. rosea and their potential roles in its biocontrol function posed by the fungus. The results show that overexpression of both enzymes led to stronger growth inhibition of the tested plant pathogens compared to the wild-type C. rosea strain. Importantly, overexpression did not cause any clear differences in the phenotype of Arabidopsis thaliana seedlings treated with these strains. One of the enzymes, CrCDHB, showed activity on A. thaliana roots and appeared to trigger the expression of PR4, a key plant defence protein usually activated in response to pathogen attack. These findings suggest potential future applications: either by using the purified CrCDHB protein to "prime" crops before infection, or by enhancing the biocontrol ability by C. rosea through strain selection or genetic modification to overexpress these enzymes.
Mara Alicke (Wed,) studied this question.