STREPTOMYCES SPECIES ABLE TO UTILIZE SOME HERBICIDES AS NITROGEN AND CARBON SOURCES

Abstract

The present work was designed to isolate and identify some actinomycetes able to degrade
Basta (glufosinate) and Sencor (metribuzin) herbicides, which are widely used for weed
control in Egypt. Results showed that 100 isolates of actinomycetes were isolated and
purified from the rhizosphere soils of 11 different crops (barley, broad bean, clover,
cotton, corn, grape, cantaloupe, pepper, sesame, tomato and wheat) treated with
pesticides. The tolerance of the actinomycete isolates for Basta and Sencor herbicides
were determined. Results showed that, 70 out of the 100 actinomycete isolates were able
to grow on the recommended dose of Sencor (0.75 g/L) but 24 out of them were showed
a good growth on the ten folds of the recommended dose of Sencor (7.5 g/L). At the
same time, 38 actinomycete isolates grew on the recommended dose of Basta (2 g/L)
and 18 of them appeared a moderate growth on 20 g/L of Basta herbicides. In addition,
the ability of the 70 isolates to utilize the Sencor as carbon and/or nitrogen source was
studied. Results showed that, 9 out of 70 actinomycete isolates gave a good growth on
the starch nitrate agar medium containing the Sencor as a sole nitrogen source, while no
isolates were found to be able to grow on the same medium with the Sencor as a sole
carbon source.In this study, 5 isolates were biologically identified and found to be strains of
Streptomyces rectiviolaceus, S.roseolus, S.albosporeus subsp abilomycaticus, S. herbaricolor and S.
aureomonopodiales.