Diversity and Potential Plant Growth-Promoting Traits of Cultivable Bacteria Associated with Three Halophytes

Salt-tolerant bacteria associated with halophytes enhance plant resistance to environmental stress and promote plant growth through their metabolic activities. The current study explored the diversity and potential of bacteria associated with three halophytes from the salt-affected land of Wujiaqu, Xinjiang, China. The cultivable bactria were isolated from Salicornia europaea L., Kalidium foliatum (Pall.) Moq., and Suaeda aralocaspica , by using the culture-dependent method. The isolated bacteria were classified based on the differences between their 16S rRNA gene sequences and screened for plant growth-promoting traits. Our findings showed that the bacteria isolated from selected plants’ parts (roots and shoots) and soil (rhizosphere and bulk) belonged to 567 strains, four phyla, six classes, 25 orders, 36 families, and 66 genera. This study revealed that the tested strains could possess one or more plant beneficial traits. Among them, 20 strains representing Bacillu s, Streptomyces , Isoptericola , and Nocardiopsis species exhibited several plant growth-promoting activities in vitro , including phosphate-solubilization, nitrogen fixation, siderophore production, cell wall degrading enzymes such as protease, and cellulase. Our findings demonstrated that halophytes are a source of plant-beneficial bacteria, which may adapt to various conditions and enhance plant development and fitness in challenging environmental situations.