Title: Rhizobium and Legume Nodulation: A Molecular Dialogue
Abstract: Soil bacteria belonging to the genera Rhizobium, Bradyrhirobium and Azorhizobium, collectively referred to as rhizobia, elicit the formation on legume roots (and stems of some species) of specific organs, the nodules, in which they fix nitrogen. The symbiosis between rhizobia and legumes produce about the same amount of ammonia worldwide as the chemical industry of nitrogen fertilizers and this fixation occurs in nodules. It is therefore important to understand by which mechanisms rhizobia induce nodule formation. These symbiotic associations are specific: every rhizobial strain has a definable host-range (Young, Johnston 1989). The mechanisms by which rhizobia infect legumes are varied. In the Rhizobium meliloti/alfalfa symbiosis, the bacteria induce the formation of marked curls at the tip of root hairs, and then the formation of tubular structures, the infection threads, which grow through the root hairs and the root cortex (see the review of Brewin 1991). At some distance from the advancing infection thread, the induction of cell divisions in the root cortex further leads to the formation of a nodule primordium and a nodule meristem. The functioning of the meristem gives rise to a nodule.
Publication Year: 1993
Publication Date: 1993-01-01
Language: en
Type: book-chapter
Indexed In: ['crossref']
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Cited By Count: 21
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