Interaction between grass endophytes and mycorrhizas in Bromus setifolius from Patagonia, Argentina

Abstract

The interaction between grass endophytes and mycorrhizas of Bromus setifolius from Patagonia, Argentina was examined. To determine effects of the endophyte (Neotyphodium sp.) on the colonisation of B. setifolius by arbuscular mycorrhizal fungi (AM), we analysed roots collected from the field and we also experimentally evaluated the association. Two populations of B. setifolius differing in endophyte colonisation were grown in either presence or absence of AM fungi using two different sources of soil. We also analysed the combined influence of these fungi on host growth. Roots of endophyte-colonised populations (E+) obtained from the field showed a higher frequency of colonisation by AM fungi than noncolonised populations (E-). The assay showed that there was a significant difference in the extent of colonisation of roots between the two populations used. E+ population roots were colonised more extensively than those of E- populations. The E+ population also showed increased growth characteristics in comparison to the E- population. The source of soil did not affect any of the host parameters analysed. For the first time, a positive interaction between Neotyphodium endophytes and arbuscular mycorrhiza is reported.