Colony morphology of high temperature tolerant mutants of USDA 110 obtained by ion-beam microbial mutation-breeding technology

イオンビーム微生物突然変異育種技術によって得られたダイズ根粒菌USDA110高温耐性変異株のコロニー形状

武田 喜代子; 手島 光平; 佐藤 勝也; 鳴海 一成; 横山 正*

Takeda, Kiyoko; Tejima, Kohei; Sato, Katsuya; Narumi, Issei; Yokoyama, Tadashi*

In order to prevent deterioration in viability of inoculants in biofertilizers exposed to high temperature, we are trying to improve a phenotypic character concerning high temperature tolerance in USDA 110, which is a worldwide superior inoculant to soybean. In this study, ion-beam microbial mutation-breeding technology is used to generate high temperature tolerant mutants. We obtained 9 high temperature tolerant mutants that can survive at 45C for 5 days. These mutants were classified into 3 groups in terms of differences in colony morphology and colony size. We will carry out further characterization of those isolates in terms of temperature tolerant and symbiotic characters.