LAUSR

ABSTRACT The effect of a soil thermophilic bacteria (STB), Ureibacillus sp. 18UE/10 on the status of wheat plants was evaluated. A greenhouse assay was performed, mimicking scenarios of soil impoverishment and aridity, which included Rhizophagus irregularis, a crop enhancer AMF, for effect comparison. Treatments with strain 18, R. irregularis or both had no significant effect on biomass production, however affected plant physiology. A different partition in biomass, nitrogen and carbon content were observed, resulting in a decreased C/N ratio. Elemental analysis showed an increase in N and P content in shoots, and for treatments containing STB a decrease in the content of several toxic metals. Strain 18 had a distinct δ13C isotopic signature translating an increased stomatal conductance. ATR-IR spectroscopy revealed that root exudate influenced STB cell wall structure and increased the bacterial survival rate at 25°C. These findings show that STB can interact with a plant partner under rhizospheric conditions. GRAPHICAL ABSTRACT