Fig. 5.

Long-distance inhibition of B. subtilis by volatile ammonia produced by S. griseus in soil. Experiments were done with a wild type S. griseus, and b S. griseus ΔgcvT that lacks the glycine cleavage system. In each panel, the bottom left image shows the growth of Streptomyces in 96 well plates filled with soil with the ammonia detection plate placed on top, and top left stereo micrographs of Streptomyces colonies growing on top of the soil. The top right side shows the color change of phenol red if ammonia is produced and the corresponding B. subtilis inhibition or growth. The graphs on the bottom right side shows the quantitative measurement of the OD₆₀₀ of each well where B. subtilis was spotted. *indicates statistical significance. Note that growth of B. subtilis was inhibited significantly by wild-type S. griseus but not by its gcvT null mutant