[Transformation as a method for increasing the activity of lucerne nodule bacteria]

Transformation of lucerne nodule bacteria was tried as a method for increasing their activity. About 100 strains resistant to 1000 units/ml of streptomycin have been obtained by transformation; 34 strains were tested for the activity of nitrogen fixation in conditions of a microvegetative experiment according to the scheme: strain-donor, strain-recipient, transformed strains. The activity varied within a wide range: +/-30--40% cf. the activity of the parent strains. The transformed strains were passaged through plants and those with a still higher activity were selected. This evidence confirms the conception of Natman concerning genetic compatibility of plants and nodule bacteria when those bacterial forms whose genome corresponds to the plant genome are selected by the macrosymbiont.