Arbuscular mycorrhizal fungi enhance Leymus chinensis resistance to salinity predominantly through regulating root endosphere bacteria

Leymus chinensis is a promising grass species for restoring saline alkali grasslands, and its salt tolerance can be improved after inoculation with AMF. However, it is still unknown whether AMF can help plant adapt to saline stress by regulating plant associated microbiome of L. chinensis.

Pot experiments were conducted to investigate the effects of Rhizophagus intraradices on the growth of L. chinensis in natural saline soil through determining physicochemical indicators included biomass, ion concentration, physiological characteristics, rhizosphere soil properties and bacterial communities in the rhizosphere, root and shoot endosphere.

The results demonstrated that R. intraradices significantly increased the biomass of L. chinensis and had a positive impact on ion absorption balance and physiological regulation. More importantly, the beneficial bacteria within rhizosphere, root and shoot endosphere were enriched. The microbial interaction networks in the rhizosphere, root and shoot endosphere became more complex and modular, with the changes of keystone taxa. Moreover, the correlation between microbial and plant biomass indicators has been strengthened. Microbial interaction networks had more effect than microbial diversity in promoting plant growth. Compared with the rhizosphere and shoot endosphere bacteria, the root endosphere bacteria regulated by AMF plays a greater role in improving biomass of L. chinensis.

Bacterial interaction patterns in the rhizosphere, root and shoot endosphere contribute to the growth of L. chinensis with AMF inoculation. Root bacterial community regulated by AMF play an important role in L. chinensis resistance to salinity.