# Claroideoglomus etunicatum affects the diversity and composition of the rhizosphere microbial community to help tall fescue resist saline–alkali stress

## TL;DR

This study shows how a specific fungus helps tall fescue grow better in salty soils by changing the types of microbes around its roots.

## Contribution

The study reveals how Claroideoglomus etunicatum interacts with rhizosphere microbes to enhance plant growth under saline–alkali stress.

## Key findings

- AMF increased plant biomass in saline–alkali soil.
- AMF altered the diversity and composition of bacterial and fungal communities.
- AMF promoted plant growth by regulating bacterial community diversity.

## Abstract

Arbuscular mycorrhizal fungi (AMF) and plant rhizosphere microbes reportedly enhance plant tolerance to abiotic stresses and promote plant growth in contaminated soils. Soil salinization represents a severe environmental problem. Although the influence of AMF in the phytoremediation of saline–alkali soils has been fully demonstrated, the underlying interactive mechanisms between AMF and rhizosphere microbes are still unclear.

A greenhouse pot experiment was conducted to explore the effects of AMF (Claroideoglomus etunicatum) on tall fescue growth promotion and the rhizosphere microbial community in saline–alkali soils. We aimed to investigate the mechanism of AMF affecting plant growth under saline–alkali stress conditions via interactions with rhizosphere microbes.

We found that AMF significantly increased plant shoot, root, and total biomass in saline–alkali stress soil. AMF significantly increased the diversity of bacterial and fungal communities and altered their composition. For bacteria, the AMF inoculation treatment (M+) showed higher relative abundance of Proteobacteria, Actinobacteriota, and Firmicutes and lower relative abundance of Acidobacteriota and Chloroflexi compared to the no-AMF application treatment (M−). For fungi, the M+ treatment showed lower relative abundance of Ascomycota and higher relative abundance of Mortierellomycota compared to the M− treatment. Furthermore, structural equation modeling (SEM) revealed that AMF promoted plant growth under saline–alkali stress conditions mainly by regulating the diversity of bacterial communities in the rhizosphere soil.

This study provides a theoretical basis for improving plant adaptation to saline–alkali stress through soil microbial management practices.