Endophytic infection by a transformed strain of wild bacteria

We were able to inoculate a model grass species Brachypodium distachyon, a distant relative of the source plant of the endophyte, and demonstrate that the bacteria can grow to occur both root cortex tissue and the root surface. While the bacteria we inoculated under sterile conditions, a similar method is likely capable of inoculating plant in-field, simply by soaking the seeds in bacterial culture prior to planting.

Our experimentation demonstrated that our bacteria can infect a grass plant under near-real-world conditions (but for biosafety, the system was contained). B. distachyon diverged from the original host, switchgrass (Panicum virgatum) 51.6 ± 7.9 (SD) million years ago (Vicentini et al. 2008). B. distachyon is more closely related to the major cereal crops (rice, wheat, corn, barley, rye and oats) than it is to switchgrass. Because of the cereal crops’ relationship to the plant we reinfected, we hypothesize that this endophytic bacteria can help promote growth and health in these important food crops.

Figure 1. 3 weeks post inoculation on plant roots. A) FCP2-01 forming large colonies about 2 mm long in B. distachyon roots B) Detail of panel A. C) FCP2-01 growing between plant cells on the root surface. D) Detail of colonies on root epidermis.
4 weeks colonization
Figure 2. 4 weeks post inoculation on plant roots. A) FCP2-01 on B. distachyon roots. B) FCP2-0 colonizing root hairs. C) FCP2-01 growing on epidermis of the root. D) Enlarged image of panel C.
4 weeks colonization


Vicentini A, Barber JC, Aliscioni SS, Giussani LM, Kellogg EA. The age of the grasses and clusters of origins of C4 photosynthesis. Global Change Biology. 2008 Dec;14(12):2963-77.