ISOLATION AND IDENTIFICATION OF NATIVE EGYPTIAN CURDLAN PRODUCING AGROBACTERIUM ISOLATE

Abstract

One hundred and eighty bacterial isolates were isolated from different soil samples and different crown galls from some plants (grape, apple, peach) grown in Egyptian soil in different area. Gram stains were applied on all isolates and the results showed that 120 isolates were Gram negative and 60 strains were Gram positive. The Gram negative isolates were selected for pathogenicity tests and were used to infect some hosts (grape, tomato and kalanchoe). The results showed that about 60 isolates cause infections of the above mentioned plants, these isolates were subjected to grow on some selective media as aniline blue medium and Congo red medium to detect curdlan producer isolates. The results obtained indicated that seven isolates give positive reaction toward curdlan production, three isolates were selected for production of curdlan after some chemical analysis and the most potent isolate was selected for optimization and identification. The potent isolate have been identified by morphological, biochemical and phylogenetic analyses.