Evaluation of colonization and mutualistic endophytic symbiosis of with tomato and Bermuda grass seedlings.

is generally considered a bacterium associated with animal microbiomes. However, we present evidence that may also mutualistically colonize roots of plant species, even to the extent that it may become endophytic in plants. In this study we used GFP tagged to observe its colonization and effects on tomato () and Bermuda grass () seedling development and growth. Inoculation with the bacterium significantly improved root development of both seedlings tested. Treatment also increased the photosynthetic pigments in Bermuda grass seedlings. However, effects on shoot length in both seedlings were not significant. This bacterium was found to produce indole acetic acid (IAA) up to 8.68 ± 0.43 µg ml in the broth medium amended with tryptophan. Effects on seedling root growth could, in part, be explained by IAA production. Bacteria successfully colonized the root surfaces and interiors of both seedlings. Tagged bacteria expressing the GFP were observed in the vascular tissues of Bermuda grass seedling roots. Seedlings with bacteria showed greater survival and were healthier than seedlings without bacteria, indicating that set up a successful mutualistic symbiosis with seedlings. is not commonly considered to be a plant endophyte but is more generally considered to be a crop contaminant. In this study we show that may also be an endophyte in plant tissues.