Molecular Biology of Infection and Nodule Development in Discaria trinervis?Frankia Actinorhizal Symbiosis

LEANDRO IMANISHI; LUCIANO ANDRÉS GABBARINI; CLAUDIO VALVERDE; EUGENIA CHAIA; LUIS GABRIEL WALL; SERGIO SVISTOONOFF

Biological Nitrogen Fixation

Wiley-Blackwell

Año: 2015; p. 433 - 440

To cope with nitrogen deficiency, some plants evolved the capacity to form nitrogen-fixing root nodules in association with soil bacteria. This ability is restricted to two groups of plants: legumes and Parasponia (Cannabaceae) that interact with Gram-negative Proteobacteria collectively called rhizobia, and actinorhizal plants, a group of 220 species of Fagales, Cucurbitales, or Rosales, that interact with Gram-positive actinomycetes of the genus Frankia (Vessey et al., 2005). All these plants are phylogenetically related and clustered together in the Fabid clade, which also contains numerous nonnodulating taxons. However, nodulation is not an ancestral trait, it probably appeared independently 12?16 times during the evolution of Fabids (Doyle, 2011). Fabids appear to have evolved a predisposition to develop nitrogen-fixing nodules, which is not found in any other group of plants. The genetic basis of this predisposition is not well understood.