Pantoea alhagi, a novel endophytic bacterium with ability to improve growth and drought tolerance in wheat

A novel strain LTYR-11Z(T) that exhibited multiple plant growth promoting (PGP) traits was isolated from the surface-sterilized leaves of Alhagi sparsifolia Shap. (Leguminosae), which reprsents one of the top drought tolerant plants in north-west China. Phylogenetic analysis of 16S rRNA gene sequences and multilocus sequence analysis based on partial sequences of atpD, gyrB, infB and rpoB genes revealed that strain LTYR-11Z(T) was a member of the genus Pantoea, with Pantoea theicola NBRC 110557(T) and Pantoea intestinalis DSM 28113(T) as the closest phylogenetic relatives. The results of DNA–DNA hybridization, phenotypic tests and fatty acid analysis confirmed that strain LTYR-11Z(T) represents a novel species of the genus Pantoea, for which we propose the name Pantoea alhagi sp. nov. Confocal microscopy observation revealed that strain LTYR-11Z(T) effectively colonizes the rhizoplane of both Arabidopsis and wheat. Strain LTYR-11Z(T) was able to promote the growth of wheat enhancing its resistance to drought stress. Strain LTYR-11Z(T) led to increased accumulation of soluble sugars, decreased accumulation of proline and malondialdehyde (MDA), and decreased degradation of chlorophyll in leaves of drought-stressed wheat. Our findings will contribute to the development of a novel biotechnological agent to improve the adaptation of crop plants to drought in arid ecosystems.