CONTROLLING THE EXPRESSION OF BACTERIAL GENES DURING ROOT NODULE DEVELOPMENT

摘要

We have been testing a simple strategy for triggering or repressing the expression of bacterial genes conceivably at any point in nodule development. It involves the use of IPTG (isopropyl thiogalactoside) as inducer of genes controlled by lac promoter/operators and the upregulated represser gene lacf. Most of our experiments have involved Rhizobium etli CE3 and its host Phaseolus vulgaris, but we have also demonstrated the efficacy of this induction system in the Sinorhizobium meliloti - alfalfa symbiosis. Apparently, IPTG is taken up by the roots and nodules of these plants in sufficiently undegraded concentrations that induction even in the most interior portions of the nodule is possible.