Transfer Gen inaZ pada Beberapa Galur Bradyrhizobium japonicum Toleran Asam-Al

Abstract

The objective of this research was to study the expression of ice maclearion gene (inaZ) in several Bradyrlxizobizmx japonicum acid-Al tolerant strains in free living and bacteroid stage. The test strains, i.e. 05, 09,15, 32, 38, and 45 were grown in yeast mannitol agar (YMA) supplemented with 100 pg/ml rifampicin (Rif) while Esclteriehia coli in luria agar (LA) with 250 µg/ml kanamycin (Kan). The conjugation frequency was 1.8 x 10-8 to 1.3 x 10-6 per recipient. All exconjugant of strains 05, 09, 15, 38 were able to show ice nucleation activity while strains 32, 45 showed partial activity i.e. 40% and 60% ice nucleation activity each. The root nodules formed were not related with the ice nucleation ability. The bacteroid stage ofall exconjugant suspensions were able to grow an YMA + Congo red (CR) + Rif but only six ofthem could grow on YMA + CR+ Rif+ Kan.