title: Order of arrival structures arbuscular mycorrhizal colonization of plants.
abstract: Priority effects - the impact of a species' arrival on subsequent community development - have been shown to influence species composition in many organisms. Whether priority effects among arbuscular mycorrhizal fungi (AMF) structure fungal root communities is not well understood. Here, we investigated whether priority effects influence the success of two closely related AMF species (Rhizophagus irregularis and Glomus aggregatum), hypothesizing that a resident AMF suppresses invader success, this effect is time-dependent and a resident will experience reduced growth when invaded. We performed two glasshouse experiments using modified pots, which permitted direct inoculation of resident and invading AMF on the roots. We quantified intraradical AMF abundances using quantitative PCR and visual colonization percentages. We found that both fungi suppressed the invading species and that this effect was strongly dependent on the time lag between inoculations. In contrast to our expectations, neither resident AMF was negatively affected by invasion. We show that order of arrival can influence the abundance of AMF species colonizing a host. These priority effects can have important implications for AMF ecology and the use of fungal inocula in sustainable agriculture.
authors.affiliation: Department of Ecological Science, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV, Amsterdam, the Netherlands.
authors.forename: Gijsbert D A
authors.identifier: http://orcid.org/0000-0002-5426-2562
authors.initials: GDA
authors.lastname: Werner
authors.affiliation: Department of Ecological Science, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV, Amsterdam, the Netherlands.
authors.forename: E Toby
authors.initials: ET
authors.lastname: Kiers
mesh_terms: D015169:Colony Count, Microbial; D003890:Desiccation; D055137:Glomeromycota / Q000254:growth & development*; D058865:Introduced Species; D046913:Medicago truncatula / Q000382:microbiology*; D038821:Mycorrhizae / Q000254:growth & development*; D063245:Plant Development; D013045:Species Specificity; D013997:Time Factors
keywords: arbuscular mycorrhizal fungi (AMF); arrival order; colonization; community composition; mutualism; priority effects; soil ecology; symbiosis