EVERYDAY SCIENCE

Detailed explanation-1: -Nitrogen-fixing actinobacteria Frankia. Frankia is a genus of soil actinomycetes in the family Frankiaceae that fix nitrogen, both under symbiotic and free-living aerobic conditions, while most rhizobia do not (Benson and Silvester, 1993).

Detailed explanation-2: -Frankia spp. are representatives of N2-fixing actinobacteria and have several unique properties. Frankia fixes N2 not only under free-living conditions, but also in symbiosis with non-legume plant species (>200) belonging to 8 families called actinorhizal plants (12, 15).

Detailed explanation-3: -This group of non-leguminous nitrogen-fixing plants includes alder trees and shrubs (Alnus sp.), bayberry and sweet gale (Myrica sp.), and sweet-fern (Comptonia peregrina).

Detailed explanation-4: -Frankia is a genus of nitrogen-fixing bacteria that live in symbiosis with actinorhizal plants, similar to the Rhizobium bacteria found in the root nodules of legumes in the family Fabaceae. Frankia also initiate the forming of root nodules.

Detailed explanation-5: -Frankia bacteria, which can induce the formation of nitrogen-fixing nodules on nonleguminous plants called actinorhizal plants, are also often devoid of nod genes.