Abstract:In order to understand the mutagenic mechanism of the rolled-leaf mutant γ-rl induced by 60Co-γ irradiation in rice, PCR technique was used to analyze four candidate genes localized in an anchored region mapped in our prior research. The results showed that one of the candidate gene, OsFMO(t), was unable to produce specific amplification fragment in the mutant γ-rl. Further analysis by PCR and Southern Hybridization revealed that a large region about 16.47 kb containing the gene of OsFMO(t) was deleted in the genome of mutant γ-rl. The results directly provide a new evidence that 60Co\|γ ray irradiation can produce a large DNA fragment deletion in plant genome. FGENESH software was utilized to predict genes probably existed in the deleted region, and the results showed that besides OsFMO(t) gene, the deleted region may also contain a putative ribonuclease H gene similar to that of Arabidopsis, a putative E2 regulation protein gene similar to that of homo sapiens, and other two genes with unknown function. Therefore, the deletion of these genes may be the main cause for the generation of mutation in γ-rl. The results of this study provided a theoretical basis for gene cloning and functional analysis related to the rolled leaf mutant γ-rl in rice.