UV irradiation method was applied to Agrobacterium tumefaciens A 136 to obtain arginine auxotrophic mutant which is applicable as a host of Ti-plasmid.
When the bacterial growth was measured at 600 ㎚, it showed the exponential phase between 7 and 16 hours after 2 % inoculation (v/v) in TY medium and the generation time of 4.8 hours. Survival rate of 1∼0.1% was reserved when irradiated at the intensity of 800 μw/㎠ for 30∼50 sec.
Fifteen mutants were selected among 5,000 colonies after UV irradiation. Two of them were identified as arginine auxotrophs, three of them as asparagine auxotrophs, and the other not as arginine, aparagine, glycine nor cysteine auxotrophs.
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