Carbon and Nitrogen Sources Influence Parasitic Responsiveness in NI-1.

Parasitic species of use hydrolytic enzymes to destroy the host cell wall. Preferent carbon and nitrogen sources suppress the expression of genes related to parasitism. Here, different nutrients were evaluated in the parasitic isolated NI-1, which was identified as . The genes and (cellobiohydrolases), (endoglucanase), and and (proteinases) were poorly expressed during the interaction between NI-1 and on PDA. However, gene expression improved on minimal medium with preferent and alternative carbon sources. Dextrin and glucose stimulated higher transcript levels than cellulose, sucrose, and glycerol. Also, ammonium stimulated a stronger parasitic responsiveness than the alternative nitrogen sources. During interaction against different phytopathogens, NI-1 detects their host differentially from a distance due to the and genes being only induced by . The and genes were induced before contact with and , while when confronted with they were stimulated until contact and overgrowth. The and genes were induced before contact against the three-host assayed. Overall, prefers to parasitize and has the capacity to distinguish between an oomycete and a fungus, but nutrient quality regulates its parasitic responsiveness.