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

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.