Induction of rice mutations by high hydrostatic pressure

High hydrostatic pressure (HHP) is an extreme thermo-physical factor that affects the synthesis of DNA, RNA and proteins and induces mutagenesis in microorganisms. Our previous studies showed that exposure to 25–100 MPa HHP for 12 h retarded the germination and affected the viability of rice (Oryza sativa L.) seeds, increased the tolerance of rice plants to cold stress and altered gene expression patterns in germinating rice seeds. However, the mutagenic effect of HHP on rice remains unknown. In this study, exposure to 25, 50, 75 or 100 MPa for 12 h HHP could efficiently induce variation in rice plants. Furthermore, presoaking time and HHP strength during HHP treatment affected the efficiency of mutation. In addition, the Comet assay revealed that exposure to 25–100 MPa HHP for 12 h induced DNA strand breakage in germinating seeds and may have been the source of mutations. Our results suggest that HHP is a promising physical mutagen in rice breeding.