Rhizobium

Definition

Rhizobium is a genus of gram-negative soil bacteria that fix nitrogen after becoming established inside the root nodules of legumes. They play a crucial role in the nitrogen cycle by converting atmospheric nitrogen into ammonia, which plants can use.

5 Must Know Facts For Your Next Test

1. Rhizobium forms a symbiotic relationship with leguminous plants, aiding in their growth by providing essential nutrients.
2. These bacteria are capable of fixing atmospheric nitrogen, making it available to plants in a usable form.
3. Rhizobium species are part of the alpha-proteobacteria class.
4. The process of nodule formation involves complex signaling between the plant and Rhizobium bacteria.
5. Effective nitrogen fixation by Rhizobium can significantly reduce the need for chemical fertilizers in agriculture.

Review Questions

• What type of relationship does Rhizobium form with leguminous plants?
• How does Rhizobium contribute to the nitrogen cycle?
• In which class of proteobacteria is Rhizobium categorized?

Related terms

Nitrogen Fixation:

A process where certain bacteria convert atmospheric nitrogen into ammonia.

Symbiosis:

A close and often long-term interaction between two different biological species.

Legume: A type of plant that has seeds in pods and often forms symbiotic relationships with nitrogen-fixing bacteria like Rhizobium.