Root endophytic fungi from date palm ( Phoenix dactylifera L.) grove of Algerian Sahara and screening of their growth promotion activities

摘要

Date palm (Phoenix dactylifera L.) is a fruit tree with economic importance cultivated in several oasis spread over the Algerian Sahara regions where the climate is hot and dry. This harsh environment has already shown to contain spontaneously plant-colonizing microorganisms with biocontrol and plant growth stimulating properties. The present study analyses for the first time, the community of roots endophytic fungi of date palm originating from three groves localized in Adrar province (Southeast of Algeria). Eighteen samples were taken from six randomly selected palms for each palm groves. Samples were aseptically collected from the youngest secondary roots.A total of 460 fungal isolates were obtained from 1800 fragments of roots, were affiliated to ten taxa according to a morphological identification. Most of the isolates were obtained from Tamentit groves growing in salt stress conditions. The other isolates were recorded from date palm trees affected by bayoud disease and from healthy trees. The dominant fungal endophytes were Fusarium sp. (30.9%) followed by Aspergillus terreus (15.4%). Four dominant isolates were tested for growth promotion of wheat via in vitro solubilization of phosphorus and production of indole acetic acid (IAA) and hydrocyanic acid HCN. Seeds sprouts were confronted directly with mycelium growing endophtes tested to ensure good root colonization. Chaetomium sp. and the species showing morphological characteristics of Botryosphaeriaceae increased significantly length, fresh and dry weight of the aerial and root parts of wheat. However, Fusarium sp. And Aspergillus terreus significantly decrease these parameters, despite, they produce more secondary metabolites. The importance and biological activity of the selected fungus was discussed. This study highlights the fungal diversity and the plant promotion potential of endophytes recovered from date palm of Algerian Sahara, and suggests extending investigation in such harsh environment, as a potential source of interesting microorganisms in the context of sustainable agriculture development.