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A study was conducted with the vine rootstock Richter 110 ( Vitis berlandieri Planch. x Vitis rupestris L.) in order to assess whether the colonisation by the arbuscular mycorrhizal fungus (AMF) Glomus intraradices (BEG 72) can delay the disease development in plants inoculated with the root-rot fungus Armillaria mellea (Vahl:Fr) Kummer, and to elucidate if the levels of polyamines (PAs) are modified in response to G. intraradices, A. mellea or by the dual infection. Four treatments were considered: control and G. intraradices-inoculated plants infected or not with A. mellea. Plant growth, mycorrhizal colonisation and disease development were monitored throughout the experiment. High performance liquid chromatography (HPLC) in combination with fluorescence spectrophotometry was used to separate and quantify free root and leaf polyamines. The slower development of pathogenic symptoms and the higher plant biomass of mycorrhizal plants inoculated with A. mellea indicate an increase of tolerance due to the AMF inoculation. The variations in free PA levels detected at the beginning of the pathogenic infection suggest that PAs may have a potential role in the signalling mechanisms of the tolerance of mycorrhizal plants against A. mellea. [ABSTRACT FROM AUTHOR]

Eighteen Prunus rootstock cultivars were inoculated with three arbuscular mycorrhizal fungi under greenhouse conditions in order to evaluate their affinity for mycorrhizal colonization. The rootstocks were peach–almond hybrids, peaches, plums and cherries of Spanish, French and Italian origin. Mycorrhizal colonization was low in plants inoculated with Glomus mosseae (Nicol. and Gerd.) Gerdemann and Trappe, and Glomus etunicatum Becker and Gerdemann. In contrast, Glomus intraradices Schenck and Smith, proved to be the most infective endophyte, achieving the highest mycorrhizal colonization rate in most of the rootstocks evaluated. Species of Prunus insititia L. were the only botanical group to show a consistently high affinity for mycorrhizal colonization with G. intraradices. [Copyright &y& Elsevier]