Gram-Negative Nitrogen-Fixing Bacteria Found in Association with Plant Roots Are

Question

Gram-negative nitrogen-fixing bacteria found in association with plant roots are
A) alphaproteobacteria.
B) betaproteobacteria.
C) cyanobacteria.
D) gammaproteobacteria.
E) deeply branching bacteria.

Accepted Answer

Alphaproteobacteria include many species that are capable of nitrogen fixation and are often found in association with plant roots, such as the Rhizobium and Bradyrhizobium genera.