Arbuscular Mycorrhiza and Nitrification: Disentangling Processes and Players by Using Synthetic Nitrification Inhibitors
Martin Dudáš, Petra Pjevac, Michala Kotianová, Kateřina Gančarčíková, Martin Rozmoš, Hana Hršelová, Petra Bukovská, Jan Jansa
Abstract
Nitrogen is one of the most important elements for all life on Earth. In soil, N is present in various chemical forms and is fiercely competed for by various microorganisms as well as plants. Here, we address competition for reduced N (ammonia) between ammonia-oxidizing prokaryotes and arbuscular mycorrhizal fungi. These two functionally important groups of soil microorganisms, participating in nitrification and plant mineral nutrient acquisition, respectively, have often been studied in separation in the past. Here, we showed, using various biochemical and molecular approaches, that the fungi systematically suppress ammonia-oxidizing bacteria to an extent similar to that of some widely used synthetic nitrification inhibitors, whereas they have only a limited impact on abundance of ammonia-oxidizing archaea. Competition for free ammonium is a plausible explanation here, but it is also possible that the fungi produce some compounds acting as so-called biological nitrification inhibitors.