The purpose of this study was to investigate the composition, diversity, distribution, and growth promotion activity of endophytic bacteria isolated from L. ruthenicum Murr. Consequently, a total of 109 endophytic bacteria affiliated to 3 phyla, 12 orders and 36 genera were isolated using nine different selective media, from which, Actinobacteria was the dominant taxon containing seven orders at the phylum level; Micrococcales showed the highest diversity containing 12 genera at the family level. Based on PAST and SPSS analysis, species diversity and abundance were mostly isolated from nutritious soil condition (22 genera) and root tissue (27 genera). Furthermore, growth phase showed significant effect on the endophytic bacteria community (28 genera at dormancy and 17 genera at fluorescence stage). With regard to ex situ plant growth-promoting activities, Streptomyces dominated and exhibited broad ability in terms of their potential to grow on nitrogen-free media, synthesize cellulase and lipase enzymes. Characterization of potential plant-beneficial traits indicate that endophytic bacteria exhibited a number of positive activities, including potential diazotrophy (n = 66), phosphate-solubilizing (n = 6), production of lipase (n = 21) and cellulose (n = 35). Two strains, representing Bacillus sp. EGI 63071 and EGI 63106, were found to be effective in promoting the growth of Triticum aestivum (wheat: Xindong No.18) seedling under salt stress conditions.
Keywords: Diversity; Endophytes; Environmental microbiology; Growth promotion; Halophyte; Lycium ruthenicum.