Importance of glutathione in the nodulation process of peanut (Arachis hypogaea)

ELIANA BIANUCCI, MARÍA DEL CARMEN TORDABLE, ADRINA FABRA, STELLA CASTRO

PHYSIOLOGIA PLANTARUM

Blackwell

Año: 2008 vol. 134 p. 342 - 347

0031-9317

Glutathione (GSH) appears to be essential for proper development of the root nodules during the symbiotic association legume-rhizobia in which the entry of rhizobia involves the formation of infection threads. In the particular case of peanut-rhizobia symbiosis, the entry of rhizobia occurs by the mechanism of infection called "crack entry", i.e., entry at the point of emergence of lateral roots. We have previously demonstrated the role of GSH content of Bradyrhizobium sp. SEMIA 6144 during the symbiotic association with peanut using a GSH-deficient mutant obtained by disruption of the gshA gene, encoding ã-glutamylcysteine synthetase (ãECS), which was able to induce nodules in peanut roots without alterations in the symbiotic phenotype. In order to investigate the role of the peanut GSH content in the symbiosis, it was used the compound L-buthionine-sulfoximine (BSO), a specific inhibitor of ãECS in plants. There were not differences in the plant growth and the typical anatomic structure of the peanut roots when the plants grew in the Fahraeus medium either in presence or absence of 0.1 mM BSO. However, the GSH content was reduced by 51% after treatment with BSO. The BSO-treated plants inoculated with wild-type or mutant strains of Bradyrhizobium sp. showed a significant reduction in the number and dry weight of nodules suggesting that GSH content could play an important role in the nodulation process of root peanut with Bradyrhizobium sp.