Resumen

FREIXAS, J. A; REYNALDO, Inés M  y  NAPOLES, María C. INFLUENCE OF DROUGHT ON THE SET nitrogen metabolism during symbiosis Bradyrhizobium-soybean. cultrop [online]. 2010, vol.31, n.2, pp.00-00. ISSN 0258-5936.

Soybean (Glycine max L. Merr.) establishes symbiosis with N2-fixing bacteria of the Rhizobia group, such as Bradyrhizobium sp. Specific molecules secreted by Bradyrhizobium, named nodulation factors, play a pivotal role in the development of root nodule. Inside nodules, rhizobia are differentiated into bacteroids, which reduce atmospheric nitrogen into ammonia. The major part of ammonia is assimilated into glutamine, which participates indirectly in nodule ureide synthesis. Among the leguminous family, soybean is one of the most sensitive to drought stress, which leads to a significant decrease in the biological nitrogen fixation (BNF). Drought-sensitive soybean genotypes accumulate ureides during drought stress; however, drought-tolerant genotypes have lower shoot ureide concentrations, which seem to alleviate drought stress on BNF. Researches based on new tools to increase BNF have been a priority during the last decade. Manganese fertilization under moderate drought conditions increases the catabolism of ureides and N2 fixation in soybean. The enzyme 1-aminocyclopropane-1-carboxylate (ACC) deaminase in Rhizobium cleaves ACC, the immediate precursor of ethylene in plants, decreasing the inhibitory effect of ethylene on nodulation. Induction of nodulation genes in Bradyrhizobium has positive effects on soybean growth under moderate drought stress. The aim of this review is focused to enclose new molecular targets that allow improving BFN in soybean under drought stress conditions

Palabras clave : soybeans; Bradyrhizobium; drought stress; nodulation; enzymes; nitrogenase; ureides.

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