Isolation and identification of indigenous Arbuscular mycorrhizal fungi (AMF) symbiosis with crops in some Iran regions with drought conditions

Plants infected by arbuscular mycorrhizal fungi can tolerate and recover more rapidly from different biotic and abiotic stresses such as soil water deficits than uninfected plants. Thereby study of the dominant mycorrhiza species in the fields under drought stresses is very useful for increasing crop productivity in these conditions and promising for biological fertilizer production in the future. The objective of this research was to study the variations in morphological and molecular diversity of arbuscular mycorrhizal fungi (AMF) and identification of dominant AMF in wheat and barley fields of some arid and semi arid regions of Iran. For this purpose, about 66 samples containing root and rhizospher soils of wheat and barley plants were collected from some arid and semi arid regions of Iran (Isfahan, Tehran, Ghazvin, Arak, Tabriz). After trap culture of observed mycorrhiza in the samples, they were identified using morphological and molecular techniques. The ITS-rDNA of AMF in root DNA extracts of wheat and barley amplified with the primer pair LSU-Glom1/SSU-Glom1 as specific primer for AMF and ITS4/ITS5 as general primers in the first and second reactions of PCR (nested PCR), respectively. Aliquots of the positive second PCR products were cloned. Positive colonies were digested with Taq1. The restriction fragment length polymorphism (RFLP) patterns of digested samples were compared and 1-3 representatives of each pattern at each cloning reaction were sequenced. Morphological and molecular diversity of AMF showed that more than 90% AMF observed in the regions belong to genus Glomus which coordinates with morphological studies and followed by G. intraradices. Also these studies confirmed presence of following species in some regions: G. fasciculatum, G. geosporum, G. sinosum, G. constrictum, G. macrocarpum and Glomus sp. and Acaulospora (Acaulospora sp.). It is important to note that the species G. etunicatu and G. dimorphicum were not detected in the morphological studies and Glomus mosseae was the most dominant AMF species in the all studied regions.