Mutation breeding is based on the induction of genetic variations; hence knowledge of the frequency and type of induced mutations is of paramount importance for the design and implementation of a mutation breeding pro...Mutation breeding is based on the induction of genetic variations; hence knowledge of the frequency and type of induced mutations is of paramount importance for the design and implementation of a mutation breeding program. Although γ ray irradiation has been widely used since the 1960 s in the breeding of about 200 economically important plant species, molecular elucidation of its genetic effects has so far been achieved largely by analysis of target genes or genomic regions. In the present study, the whole genomes of six γ-irradiated M2 rice plants were sequenced; a total of 144–188 million high-quality（Q〉20） reads were generated for each M2 plant, resulting in genome coverage of 45 times for each plant. Single base substitution（SBS） and short insertion/deletion（Indel） mutations were detected at the average frequency of 7.5×10^-6～9.8×10^-6 in the six M2 rice plants（SBS being about 4 times more frequent than Indels）. Structural and copy number variations, though less frequent than SBS and Indel, were also identified and validated. The mutations were scattered in all genomic regions across 12 rice chromosomes without apparent hotspots. The present study is the first genome-wide single-nucleotide resolution study on the feature and frequency of γ irradiation-induced mutations in a seed propagated crop; the findings are of practical importance for mutation breeding of rice and other crop species.展开更多
基金supported by the National Natural Science Foundation of China(No.11275171)the National Key Technology R&D Program of China(No.2014BAA03B04)the Mutation Breeding Project of the Forum for Nuclear Cooperation in Asia(FNCA)
文摘Mutation breeding is based on the induction of genetic variations; hence knowledge of the frequency and type of induced mutations is of paramount importance for the design and implementation of a mutation breeding program. Although γ ray irradiation has been widely used since the 1960 s in the breeding of about 200 economically important plant species, molecular elucidation of its genetic effects has so far been achieved largely by analysis of target genes or genomic regions. In the present study, the whole genomes of six γ-irradiated M2 rice plants were sequenced; a total of 144–188 million high-quality（Q〉20） reads were generated for each M2 plant, resulting in genome coverage of 45 times for each plant. Single base substitution（SBS） and short insertion/deletion（Indel） mutations were detected at the average frequency of 7.5×10^-6～9.8×10^-6 in the six M2 rice plants（SBS being about 4 times more frequent than Indels）. Structural and copy number variations, though less frequent than SBS and Indel, were also identified and validated. The mutations were scattered in all genomic regions across 12 rice chromosomes without apparent hotspots. The present study is the first genome-wide single-nucleotide resolution study on the feature and frequency of γ irradiation-induced mutations in a seed propagated crop; the findings are of practical importance for mutation breeding of rice and other crop species.
