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

BIANUCCI, E.; TORDABLE,M.; FABRA,A.; CASTRO,S.

PHYSIOLOGIA PLANTARUM

Año: 2008 vol. 134 p. 342 - 347

0031-9317

Glutathione (GSH) appears to b 34 e essential for proper development of the root nodules during  the symbiotic association legume-rhizobia in which the entry of rhizobia involves theformation of infection threads. In the particular case of peanut-rhizobia symbiosis, the entryof rhizobia occurs by the mechanism of infection called “crack entry”, i.e., entry at the pointof emergence of lateral roots. We have previously demonstrated the role of GSH content ofBradyrhizobium sp. SEMIA 6144 during the symbiotic association with peanut using a GSH40deficient mutant obtained by disruption of the gshA gene, encoding ã-glutamylcysteinesynthetase (ãECS), which was able to induce nodules in peanut roots without alterations in thesymbiotic phenotype. In order to investigate the role of the peanut GSH content in thesymbiosis, 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 presenceor 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