Medicago truncatula

Medicago truncatula A17 branch

Medicago truncatula, commonly known as the barrel medic, is a small legume used as a model organism in the study of plant biology, particularly in the area of symbiotic nitrogen fixation. This species belongs to the genus Medicago, which includes over 80 species of leguminous plants, and is closely related to the agriculturally important crop, alfalfa (Medicago sativa).

Description

Medicago truncatula is a perennial herb that typically grows to a height of 10-60 cm. It has a deep taproot system which allows it to access water from deep within the soil, making it resilient to drought conditions. The leaves are trifoliate, with each leaflet being obovate to oblong and ending in a sharp point. The plant produces small, yellow flowers which are followed by coiled, spiny seed pods, characteristic of many members of the Medicago genus.

Habitat and Distribution

Originally native to the Mediterranean region, Medicago truncatula has been introduced to many parts of the world, including North America and Australia, where it grows in grasslands, roadsides, and disturbed areas. It prefers well-drained soils and can thrive in a variety of soil types.

Importance in Research

Medicago truncatula has been adopted as a model organism for legume research due to its relatively small genome size, self-fertility, and ease of genetic transformation. It is particularly valuable for studying the process of symbiosis between legumes and nitrogen-fixing bacteria known as rhizobia. This symbiotic relationship results in the formation of root nodules, where nitrogen fixation takes place, converting atmospheric nitrogen into a form that can be used by the plant. This process is critical for understanding sustainable agricultural practices and improving crop yields.

Research on Medicago truncatula has led to significant advances in our understanding of plant-microbe interactions, plant development, and the genetic basis of stress responses. The Medicago truncatula genome has been fully sequenced, providing a valuable resource for comparative genomics studies and for identifying genes involved in important biological processes.

Cultivation and Uses

While Medicago truncatula is not widely cultivated for agricultural purposes, it serves as an important cover crop and green manure, improving soil health and fertility through its nitrogen-fixing capabilities. It is also used in research settings for genetic studies and for understanding the mechanisms of disease resistance and stress tolerance in legumes.

See Also

• Legume
• Nitrogen fixation
• Symbiosis
• Genome sequencing