Cross-inoculation of Andropogon virginicus rhizobiome enhances fungal diversity and network complexity in maize (Zea mays) rhizosphere under drought

Rhizosphere soil microbes are increasingly recognized for their significant roles in enhancing plant resilience to abiotic stress and stimulating plant growth. Rhizobiome adapted to dry conditions can enhance drought tolerance in crops by cross-inoculation. However, changes in the rhizobiome that help in conferring drought tolerance remain poorly understood. Here, by conducting a drought-manipulating greenhouse experiment, we characterized changes in the rhizobiome of maize (Zea mays) after cross-inoculation of rhizosphere soil collected from drought-adapted Andropogon virginicus (Andropogon rhizobiome). Results showed that maize inoculated with Andropogon rhizobiome reduced oxidative damage of leaves under drought. Drought stress increased the species richness and Shannon diversity of the fungal community. Additionally, the inoculation of Andropogon rhizobiome induced a more significant increase in fungal diversity than the inoculation of organic rhizobiome. The increase of fungal diversity was positively correlated with the increased drought resistance of maize. Bacterial richness and diversity under the inoculation of Andropogon rhizobiome were negatively affected by drought stress. In addition, increased positive links in the fungal network in the Andropogon inoculation under drought conditions as compared with the ambient controls suggests more cooperation between fungal taxa to cope with drought stress. Collectively, our findings indicate that the fungal but not bacterial community diversity and network complexity stimulates drought tolerance in maize by cross-inoculation of the rhizobiome from A. virginicus. This study provides important insights that will enhance theoretical understanding and applications of plant–rhizobiome associations to promote drought resilience in agricultural crops.