The synergy effect of arbuscular mycorrhizal fungi symbiosis and exogenous calcium on bacterial community composition and growth performance of peanut (Arachis hypogaea L.) in saline alkali soil.

Peanut (Arachis hypogaea. L) is an important oil seed crop. Both arbuscular mycorrhizal fungi (AMF) symbiosis and calcium (Ca2+) application can ameliorate the impact of saline soil on peanut production, and the rhizosphere bacterial communities are also closely correlated with peanut salt tolerance; however, whether AMF and Ca2+ can withstand high-salinity through or partially through modulating rhizosphere bacterial communities is unclear. Here, we used the rhizosphere bacterial DNA from saline alkali soil treated with AMF and Ca2+ alone or together to perform high-throughput sequencing of 16S rRNA genes. Taxonomic analysis revealed that AMF and Ca2+ treatment increased the abundance of Proteobacteria and Firmicutes at the phylum level. The nitrogen-fixing bacterium Sphingomonas was the dominant genus in these soils at the genus level, and the soil invertase and urease activities were also increased after AMF and Ca2+ treatment, implying that AMF and Ca2+ effectively improved the living environment of plants under salt stress. Moreover, AMF combined with Ca2+ was better than AMF or Ca2+ alone at altering the bacterial structure and improving peanut growth in saline alkali soil. Together, AMF and Ca2+ applications are conducive to peanut salt adaption by regulating the bacterial community in saline alkali soil.