B. kururiensis is a diazotrophic bacterium originally isolated from polluted aquifer environment. This work assessed the ability of B. kururiensis to endophytically colonise rice plantlets, under gnotobiotic conditions, by monitoring of infected plant tissues with bacterial counting, scanning electron microscopy (SEM) and 16S rDNA analysis. Observation of infected roots with SEM revealed B. kururiensis colonisation predominantly on hairy zones. Infection route was monitored by SEM, demonstrating endophytic colonisation primarily through the endodermis, followed by spreading into xylem vessels, a possible pathway leading to aerial parts. B. kururiensis was isolated in high numbers from rice plantlets, grown with no nitrogen addition. However, addition of nitrogen compounds was a limiting factor for endophytic colonisation, as evidenced by selective invasion patterns in a dose-response experiment. Interestingly, endophytic colonisation was directly associated to an enhanced plant development. Production of bacterial auxin-like factors by B. kururiensis was tested with transgenic rice plantlets containing an auxin-responsive reporter (DR5-GUS). Our findings suggest the ability of auxin production by plant-associated B. kururiensis, which may have a stimulatory effect on plant development, as evidenced by activation of DR5-GUS. We hereby demonstrate, for the first time, the ability of B. kururiensis to endophytically colonise rice, promoting enhanced plant growth and rice production yields.