Genome analysis of the high temperature tolerant mutant of USDA110 generated by ion-beam irradiation

イオンビーム育種により作出したダイズ根粒菌の高温耐性変異株のゲノム解析

武田 喜代子*; 佐藤 勝也; 鳴海 一成*; 大野 豊; 大津 直子*; 横山 正*

Takeda, Kiyoko*; Sato, Katsuya; Narumi, Issey*; Ono, Yutaka; Otsu, Naoko*; Yokoyama, Tadashi*

Major constraint of biofertilizer utilization in agricultural practice is a viability loss of beneficial microorganisms in biofertilizers by high temperature stress during both storage and transportation. Therefore, we have tried to improve high temperature tolerance of USDA110 using carbon-ion beams accelerated by an AVF cyclotron at TIARA. Consequently, we have obtained a high temperature tolerant mutant that can maintain a high survival rate at 42 C for at least 7 days in yeast-mannitol broth medium, and named it as M14. The genome sequence of M14 was determined by a whole-genome shotgun strategy. The acquirement of high temperature tolerance in M14 could be attributed to 18 base mutations and/or a large-scale inversion (1.27 Mb). In the future, we will conduct further analysis on these mutations in order to decipher the molecular mechanisms of high temperature tolerance of M14.