Genome analysis of a high temperature tolerant mutant of USDA110 generated by ion-beam microbial mutation-breeding technology

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

We have tried to generate high temperature tolerant mutants of USDA110 using ion beam breeding technology. Consequently, we obtained a mutant, M14, which can survive at 42C for at least 7 days. The genome sequence data of M14 were accumulated using a GS Junior System. The data were then mapped to the reference sequence of strain USDA110 using a GS Reference Mapper software. About 99.5% of the reference sequence was covered with the M14 sequence. Genome comparison revealed a large-scale structural change in the circular M14 genome. Namely, a DNA region at the coordinates 4,029,225 5,299,697 (1,270,473 bp) was inverted. In addition, about 20 mutations such as base substitutions, insertions and deletions were found in M14. The acquirement of high temperature tolerance in M14 could be attributed to a large-scale inversion and/or small-scale mutations.