Plant Nitrogen Use Efficiency May Be Improved Through Symbiosis with Piriformospora indica

Abstract

Faced with increasing demand for crop production and the detrimental environmental impacts of the excessive use of fertilizers, it is important to use all available tools to increase crop nutrient use efficiency. Nutrient acquisition by plant roots is much influenced by the microbial composition and activity of the rhizosphere. Most crop plants (80%) form symbiotic associations with arbuscular mycorrhizal fungi. However, these fungi are obligatory biotrophs and therefore cannot be cultivated without the plants. Piriformospora indica is a recently discovered endophyte that mimics many of the effects of arbuscular mycorrhizal fungi but can be cultivated in axenic cultures. The aim of our work was to compare the mechanisms of nitrogen uptake and transference to the plant in Piriformospora indica and Glomus intraradices in symbiosis with tomato (Solanum lycopersicum cv Roma) root organ cultures and to evaluate the respective nitrogen use efficiencies. We found that Piriformospora indica was more efficient than Glomus intraradices in taking up nitrogen, the effect being observed even at high P concentrations.