Leaf endophytes affect mycorrhizal status and growth of co-infected and neighbouring plants

OMACINI, M., T. EGGERS, M. BONKOWSKY, A. GANGE, TH JONES

FUNCTIONAL ECOLOGY

Blackwell publishing

Año: 2006 vol. 20 p. 226 - 232

0269-8463

1.      Fungal leaf-endophytes and arbuscular mycorrhizal (AM) fungi are common constituents of natural grasslands. The probability of simultaneous presence of these two grass plant symbionts is high. 2.      We describe the results of a greenhouse experiment investigating the outcome of dual infection of a cool-season grass species, Lolium multiflorum, by the fungal endophyte Neotyphodium occultans and three species of Glomus AM fungi. 3.      Mycorrhizal colonization was investigated on monocultures of plants with or without leaf-endophytes, and on mixtures of endophyte-infected and uninfected plants. In both scenarios, endophyte-infected plants had lower levels of mycorrhizal colonisation, but in the endophyte mixtures, the presence of endophyte infected plants caused an increase in AM colonisation in non endophyte-infected conspecific neighbours. 4.      Host plant biomass, nutrient (nitrogen and phosphorus) accumulation and competitive ability were increased by endophyte presence. AM presence did not improve host performance or nutrient content (concentration or accumulation) in the presence or absence of the endophyte. 5.      Interactions between host plants and AM fungi are mediated by fungal endophyte infection. The implications of such modified interactions to ecosystem dynamics and functioning are considered.