Bacillus cereus905, one of the plant growth-promoting rhizobacteria (PGPRs), is capable of colonizing wheat roots in a large population size. From previous studies, we learned that thesodA2-encoding manganese-containing superoxide dismutase (MnSOD2) is important forB. cereus905 to survive in wheat rhizosphere. In this investigation, we demonstrated that deletion of therecAgene, which codes for the recombinase A, significantly reduced MnSOD2 expression at both the mRNA and the protein levels. Through comparison with the wild-type, the increment recAshowed a dramatic decrease in cell survival after exposure to 50 mu M paraquat or 15 mM H2O2. Evidence indicated that therecAgene ofB. cereus905 also notably regulated nutrition utilization efficiency, biofilm formation, and swarming motility. The root colonization examination showed that the increment recAhad a 1000- to 2500-fold reduction in colonization on wheat roots, suggesting that RecA plays an indispensable role in effective colonization on wheat roots byB. cereus905. Taken together, therecAgene positively regulates MnSOD2 production and nutrition utilization and protectsB. cereus905 cells against paraquat and H2O2. Besides, biofilm formation and swarming motility ofB. cereus905 are promoted by RecA. Finally, RecA significantly contributes to wheat root colonization ofB. cereus905. Our results showed the important role of RecA during physiological processes inB. cereus905, especially for colonization on wheat roots. Our findings will point out a research direction to study the colonization mechanisms ofB. cereus905 in the future and provide potential effective strategy to enhance the biocontrol efficacy of PGPR strains.