Effectiveness of arbuscular mycorrhizal fungi in the protection of date palm (Phoenix dactylifera L.) against bayoud disease

In the present study, arbuscular mycorrhizal fungi (AMF) (Glomus monosporus, Glomus deserticola, Glomus clarum and a complex of native AMF coming from the Aoufous date palm grove in the south of Morocco) have been shown to protect date palm seedlings against bayoud disease. Treatment with AMF reduced disease severity by 8-77% depending on the AMF isolate used. In addition, all mycorrhizal fungi stimulate significantly shoot height and biomass and increase the number of leaves per plant. The plants associated with Aoufous complex present the best improvement of plant growth and great effectiveness in reducing bayoud disease incidence. Moreover, the AMF induce change in activities of two defence-related enzymes (peroxidases and polyphenoloxidases). The potential involvement of this induced biochemical defence reaction in protecting date palm against bayoud is discussed. (C) 2008 Elsevier Ltd. All rights reserved.