Mutation and Selection of Agrobacterium tumefaciens Arginine Auxotroph by UV Irradiation

자외선 조사(照射)에 의한 Agrobacterium tumefaciens Arginine 요구주(要求株)의 유도와 선발

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 nm, 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 $1{\sim}0.1%$ was reserved when irradiated at the intensity of $800\;{\mu}w/cm^2$ for $30{\sim}50sec$. 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, ana the other not as arginine, asparagine, glycine nor cysteine auxotrophs.

Agrobacterium tumefaciens A 136에 자외선은 조사(照射)하여 Ti-plasmid 숙주로 이용할 수 있는 arginine 영양요구주를 선발하고자 하였다. A. tumefaciens의 생육을 600nm에서의 흡광도(吸光度)로 측정할 때 TY배지에서 2% 접종시 7시간 부터 16시간 사이에 대수기를 보였고 generation time은 4.8시간이었다. $800{\mu}w/cm^2$의 자외선 강도로 $30{\sim}50$초 조사(照射)에서 $1{\sim}0.1%$의 생존율을 보였다. 자외선 조사(照射)로 mutation을 유도한 다음 5,000개의 colony에서 15개의 mutants를 얻었으며 그 중 2개는 arginine 영양요구주였고 3개는 asparagine 영양요구주였다.