Rhizobacterial diversity, community composition, and the influence of keystone taxa on O’Neal blueberry (Vaccinium corymbosum)

Rhizosphere microbiotas play vital roles in resisting environmental stress, transforming soil nutrients, and promoting plant health, growth, and productivity. The effects of rhizosphere microbial community shaping and the characteristics and functions of keystone taxa on blueberries were comprehensively studied by examining the rhizobacteria of healthy old trees (O), young seedlings (OG), and poorly growing seedlings (OB) of O'Neal blueberries. Our results showed that rhizobacterial diversity followed the order OB > > OG > O, and the microbial community of OG was similar to that of O, while that of OB was distinctly different. The predominant rhizobacteria identified included <i>Actinobacteria</i>, <i>Proteobacteria</i>, <i>Firmicutes</i>, <i>Chloroflexi</i>, and <i>Acidobacteria</i>. <i>Firmicutes</i> were highly enriched in healthy blueberries, with <i>Bacillus</i> identified as a key genus that significantly enhanced blueberry growth when inoculated. <i>Bradyrhizobium</i> and <i>Gaiellales</i> were common core bacteria in the blueberry rhizosphere. In contrast, <i>Acidobacteria</i> were the predominant phylum in poorly growing OB, with the specific <i>Vicinamibacterales</i>-related and <i>Latescibacterota</i>-related genera acting as keystone taxa that shaped the microbial community. In addition, bacterial species in <i>Vicinamibacterales</i> might act as a potential pathogen predicted by BugBase. Taken together, these findings provide fundamental insights into the development of the blueberry rhizosphere microbial community and highlight the role of beneficial rhizobacteria, such as <i>Bacillus</i>, in enhancing blueberry growth. This knowledge could contribute to the exploitation of beneficial rhizobacteria and the prevention of pathogens in modern agriculture.