Alleviating salt stress on seedings using plant growth promoting rhizobacteria isolated from the rhizosphere soil of Achnatherum inebrians infected with Epichloë gansuensis endophyte

Background Soil salinity is a severe environmental stress, limiting plant growth and sustainable agriculture. Plant growth promoting rhizobacteria (PGPR) and Epichloë gansuensis endophyte can be used to alleviate the adverse effects of soil salinization, promote plant growth and improve resistance to biotic and abiotic stresses. Aims The present study was conducted to investigate the diversity of culturable rhizosphere soil bacteria associated with Achnatherum inebrians , as well as the effect of E. gansuensis and PGPR on the germination of A. inebrians seeds under high concentrations of NaCl. Materials and methods The PGPR strains were obtained by traditional isolation and culture techniques, and then endophyte-infected and endophyte-free A. inebrians seeds exposed to different concentrations of NaCl were inoculated with PGPR. Results A total of 990 bacterial colonies were isolated, and these were assigned to 65 species within 18 genera and 4 phyla. Principal component analysis (PCA) indicated that the rhizosphere soil of A. inebrians plants with Epichloë had differing bacterial diversity from that without Epichloë. When A. inebrians seeds were exposed to NaCl concentrations of 0, 50, 100, 200 mmol/L, seed germination was enhanced at the low salt concentration (50 mmol/L) and inhibited at the highest salt concentration (200 mmol/L). E. gansuensis significantly ( P