The composition characteristics of arbuscular mycorrhizal fungal communities associated with barley in saline-alkaline soils in Central Anatolia

ABSTRACT

Central Anatolia, which suffers from salinity, alkalinity, and drought stresses, is one of the most important cultivation regions of barley (Hordeum vulgare) in Turkey. Arbuscular mycorrhizal fungi (AMF) could promote barley production under several stresses; however, only a little information is available for AMF community composition in Turkish arable soils. In this study, barley root samples were collected from eight sites in the Central Anatolian region during the growing season (GS: April) and the harvest season (HS: July) in 2012, and the composition of AMF communities were elucidated based on the partial sequence of the AMF 18S rRNA gene using high-throughput sequencing technology. As a result, barley-AMF symbioses in this region were highly dominated by Glomeraceae (71.8% in GS and 59.2% in HS), followed by Claroideoglomeraceae (10.3% in GS and 15.9% in HS), Gigasporaceae (9.1% in GS and 13.1% in HS), and Acaulosporaceae (5.8% in GS and 7.7% in HS). Compared to Glomeraceae and Claroideoglomeraceae families, communities of Acaulosporaceae, Diversisporaceae, Paraglomeraceae, and Gigasporaceae consisted of fewer AMF species. The AMF evenness significantly increased from GS to HS. The most dominant AMF sequence, VTX00248 in the MaarjAM database, was closely related to Rhizophagus, which occupied 25.8% and 14.7% of the total AMF sequences in GS and HS, respectively. The relative abundance of AMF related to Rhizophagus tended to be reduced in HS, suggesting that the species could form mycorrhiza in the early stages of barley growth in this region. On the other hand, the relative abundance of Claroideoglomeraceae and Scutellosporaceae tended to increase in HS. Soil CaCO₃ content significantly influenced AMF community compositions in GS, while soil pH and EC showed no significant impact on AMF community compositions. Based on discriminant analysis, 11 VTXs (related Acaulospora, Claroideoglomus, Funneliformis, Gigaspora, and Glomus) showed higher abundance in the barley roots grown in the soil with relatively high CaCO₃ content, suggesting that these sequences might be adapted to such an environment.