You'll love the TED video that accompanies this story.
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The human body has about a trillion cells in it. And those trillion
cells host--either in you or on you--about 10 trillion bacteria. You
have about 30,000 genes in you; the bacteria you host have about 100
times the amount of genetic material or information. "So," says
Bassler, "when I look at you, I think of you as 1 or 10 percent human
and either 90 or 99 percent bacterial."
In the same way we humans have domesticated and now farm plants and
animals for our benefit, so (say leading soils researchers) plants
have established interdependent, symbiotic relationships with most of
the protozoa, earthworms, arthropods, algae, bacteria, and fungi that
surround their roots. The plants send food (about half of all the
carbohydrates and other nutrients they produce) down to their roots
. . . and then, through their roots, they /exude/ these nutrients (in
a liquid called /exudate/), into the soil. This exudate, in turn,
feeds the bacteria and other organisms that live in the rhizosphere
<http://en.wikipedia.org/wiki/Rhizosphere> (the area of the roots).
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