Figure 1.

Concept of plant-borne carbon tracing to root-associating rhizobacteria. Atmospheric carbon is traced from plant fixation of radioactive ¹¹CO₂ through root translocation as complex ¹¹C-photosynthates. There, that carbon source is assimilated by root-associating microorganisms. The center insert shows an overlay of images from ¹¹C-radiography (dark black regions reflect high levels of ¹¹C activity) and a green fluorescence image arising from RAM10, a green fluorescent protein (GFP) reporting strain of H. seropedicae bacteria. Regions of high root colonization seem to draw more ¹¹C.