Pararhizobium

Pararhizobium is a genus of Gram-negative, rod-shaped bacteria belonging to the family Rhizobiaceae. These bacteria are typically found in soil and are known for their ability to form symbiotic relationships with plants, particularly legumes. The genus was first described in 2007, distinguishing it from the closely related genus Rhizobium.

Members of the genus Pararhizobium are motile, possessing polar flagella. They are facultative anaerobes, meaning they can grow in the presence or absence of oxygen. Their metabolic capabilities are diverse, allowing them to utilize a range of carbon sources. A key characteristic of Pararhizobium is its capacity to fix atmospheric nitrogen in symbiosis with host plants. This nitrogen fixation occurs within specialized structures called nodules, which form on the roots of the host legume.

The symbiotic association benefits the plant by providing a readily available source of nitrogen, essential for growth. In return, the bacteria receive carbohydrates and a protected environment. While Pararhizobium shares many traits with Rhizobium, genetic and phylogenetic analyses have shown them to be distinct lineages. Research continues to explore the ecological roles and biotechnological potential of Pararhizobium species, particularly in agriculture for sustainable crop production.