Alphaproteobacteria - Characteristics

Characteristics

The Alphaproteobacteria comprise most phototrophic genera, but also several genera metabolising C1-compounds (e.g., Methylobacterium spp.), symbionts of plants (e.g., Rhizobium spp.) and animals, and a group of pathogens, the Rickettsiaceae. Moreover the precursors of the mitochondria of eukaryotic cells are thought to have originated from Rickettsia spp. (See endosymbiotic theory.). Because of their symbiotic properties, scientists often use Alphaproteobacteria of the genus Agrobacterium to transfer foreign DNA into plant genomes, and they also have many other biotechnological properties. Aerobic anoxygenic phototrophic bacteria are alphaproteobacteria that are a widely distributed marine plankton that may constitute over 10% of the open ocean microbial community.