Abstract: The genus Kineococcus is primarily found in extreme environments and plant-associated habitats, suggesting its potential for stress tolerance and plant growth promotion. However, the diversity and functional potential of this genus remain largely unexplored, mainly due to the limited availability of strains and genomic resources. In this study, 33 Kineococcus strains were isolated from the Gurbantunggut Desert and Shanshan Kumtag Desert in Xinjiang, China. Based on the overall genome relatedness indices (OGRI) and sampling origins, 12 representative Kineococcus strains were selected for polyphasic taxonomy and assessment of plant growth promoting traits. By integrating phylogenetic, morphological, physiological, chemotaxonomic, and genomic analyses, these strains were classified into nine novel species (one with two subspecies). The representative isolates exhibited various key plant growth-promoting traits, including siderophore production, cellulose degradation, organophosphate solubilization, and indole-3-acetic acid (IAA) production. This study significantly expands the strains, species, and genome resources of the genus Kineococcus, providing valuable insights into its ecological adaptation, particularly in saline-alkali tolerance, and growth-promoting potential for sustainable agriculture.

Key words: desert, Kineococcus, novel species, plant growth-promoting, polyphasic taxonomy, saline-alkali-tolerant