Soil P reduces mycorrhizal colonization while favors fungal pathogens: observational and experimental evidence in Bipinnula (Orchidaceae). Issue 11 (26th August 2020)

• Record Type: Journal Article
• Authors: Mujica, María Isabel; Pérez, María Fernanda; Jakalski, Marcin; Martos, Florent; Selosse, Marc André
• Is Part Of: FEMS microbiology ecology. Volume 96:Issue 11(2020)
• Publication Date: 2020-08-26
• Subjects: orchid mycorrhiza -- fungal root community -- fungal guilds -- orchid fertilization -- soil nutrients -- Bipinnula; Microbial ecology -- Periodicals; Microbiology -- Periodicals; 579.17
• DOI: 10.1093/femsec/fiaa178
• Languages: English
• ISSNs: 0168-6496

Abstract

ABSTRACT: Little is known about the soil factors influencing root-associated fungal communities in Orchidaceae. Limited evidence suggests that soil nutrients may modulate the association with orchid mycorrhizal fungi (OMF), but their influence on non-mycorrhizal fungi remains unexplored. To study how nutrient availability affects mycorrhizal and non-mycorrhizal fungi associated with the orchid Bipinnula fimbriata, we conducted a metagenomic investigation within a large population with variable soil conditions. Additionally, we tested the effect of phosphorus (P) addition on fungal communities and mycorrhizal colonization. Soil P negatively correlated with the abundance of OMF, but not with the abundance of non-mycorrhizal fungi. After fertilization, increments in soil P negatively affected mycorrhizal colonization; however, they had no effect on OMF richness or composition. The abundance and richness of pathotrophs were negatively related to mycorrhizal colonization and then, after fertilization, the decrease in mycorrhizal colonization correlated with an increase in pathogen richness. Our results suggest that OMF are affected by soil conditions differently from non-mycorrhizal fungi. Bipinnula fimbriata responds to fertilization by altering mycorrhizal colonization rather than by switching OMF partners in the short term, and the influence of nutrients on OMF is coupled with indirect effects on the whole fungal community and potentially on plant's health. Abstract : In situ P addition reduces mycorrhizal colonization in Bipinnula fimbriata in the short term, and this is coupled with an increase in pathogen richness.