Molecular genetic characterization of arbuscular mycorrhizal fungi associated with upland rice in Bangladesh

Understanding the community composition and diversity of arbuscular mycorrhizal fungi (AMF) in agricultural ecosystems is important for exploring their potential for use in sustainable crop production. In this study, we collected rice root samples from upland rice fields under different agricultural practices in four districts of Bangladesh (Khagrachori, Rangamati, Chattogram, and Bandarban) to estimate the AMF colonization rate and to investigate the taxonomic diversity and community composition of indigenous AMF by high-throughput Illumina amplicon sequencing. The AMF colonization rates of the rice root samples ranged between 14 and 47%, and were positively correlated with the soil pH (4.58-5.93), suggesting that more AMF colonization is likely to form under slightly acidic conditions. This result suggests that AMF colonization rate in upland rice roots might be affected by soil pH; however, no significant correlation with soil available phosphorus contents was observed. In total, eight different AMF genera were detected by amplicon sequencing. Glomus and Paraglomus were found to be the dominant genera in all the regions, followed by Scutellospora, Acaulospora, Claroideoglomus, Diversispora, Gigaspora, and Archaeospora. Shannon's diversity index and Pielou's evenness were significantly higher in the Bandarban district than the other districts, whereas Faith's phylogenetic diversity and richness showed no significant difference between the four districts. The beta diversities of AMF community composition based on the BrayCurtis dissimilarities were significantly differentiated among the districts. The soil available phosphorus contents were significantly correlated with the AMF beta diversities between the four districts. This is the first study to report on the AMF community composition and diversity in upland rice roots and on how AMF communities are affected by the soil chemical properties in different locations in Bangladesh.