Commonly abbreviated to PPFMs, these bacteria are members of the genus Methylobacterium and are commonly found in soil, dust, various fresh water supplies and on plant surfaces. Research has suggested that PPFMs can benefit host plants in a variety of ways such as promoting germination, growth and yield of sugarcane, and accumulation of vitamin B in lettuce. Their pigmentation, which is frequently pink but may also be yellow or orange, is thought to provide protection from solar UV radiation which damages the DNA of bacteria at low doses because of their small cell size.
The metabolism of PPFMs is unusual because, as their name suggests, they are able to utilize C1 compounds such as formaldehyde, methanol and methylamine. In dense and diverse communities like those found in the phyllosphere and rhizosphere, this enables them to utilize nutrients other bacteria cannot, enhancing their competitive ability.
Although gram negative, Methylobacteria often stain gram variable and do not grow on MacConkey agar. ...