Importancia del glutatión en la simbiosis rizobio-maní

ELIANA BIANUCCI, MARÍA DEL CARMEN TORDABLE, ADRIANA FABRA, STELLA CASTRO.

Los Cocos, Cordoba, Argentina

Congreso; XXII Reunion Latinoamericana de Rizobiologia; 2007

RELAR

Glutathione (GSH) is essential in the legume nodulation process which the entry of rhizobia involves the formation of infection threads. Actually, there is not information about the GSH role in the mechanism of infection that occurs by “crack entry” characteristic of peanut plant. We studied the importance of GSH in Bradyrhizobium sp. SEMIA6144 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. To investigate the involvement of the peanut GSH content in the symbiosis, a strategy aimed at modifying the GSH pool was developed using L-buthionine-sulfoximine (BSO), a specific inhibitor of ãECS in plants. Peanut seedlings were grown in the Farhaeus medium either in the presence or absence of BSO (0.1 to 1 mM). The concentration of 0.1 mM BSO did not modify the plant growth and the typical anatomic structure of the peanut roots. However, the GSH content was reduced by 51% after treatment with BSO. This concentration was chosen to further analyze the implication of GSH in the nodulation process. The BSO-treated plants and inoculated with wild-type strain showed a reduction in the number and dry weight of nodules suggesting that the peanut GSH content plays an important role in the establishment of the symbiosis.