Sequencing Characteristics Of Genomic Instability In Space Flight-Induced Purple Leaf Mutation Rice

Space environment included a variety of ionizing radiation such as electron, proton and heavy-ion. Ionizing radiation can cause genome instability, In principle, this radiation-induced genome instability will contribute to increase mutation rates in multi-generation. Genome instability encompasses a wide range of alterations, including gene mutation, microsatellite instability. Rice seed was growth on ground after space flight by Shenzhou-6 spacecraft. After three generations of continuous cultivation, we found the offspring of 4 individuals in the second generation appeared purple leave. The offsprings of purple mutation was observed both purple leave and green leave. We discovered that the purple rice trait was the performance of genome instability. To find genome sequence characteristics and molecular mechanism of space radiation induced genome instability, AFLP molecular marker technology was used to search for polymorphisms of sequence characteristics of purple rice induced by the space environment.29 polymorphism loci were detected by AFLP. By sequencing 20 polymorphism loci, we found those 14 polymorphism loci on non-coding sequence and 5 polymorphism loci on coding sequence. This result showed that space-flight induced rice genome instability mainly occurs in the non-coding region. To investigate the genome sequence characteristics of the mutation caused by space-flight,8 polymorphism loci were used to study the purple mutation.34 point mutations,1 microsatellite sequence anomalies and 4 deletion mutants were found in purple mutation. To study the genetic of the mutation, we found 43 polymorphism loci on the next generation, including 10 polymorphism loci exhibited genetic stability and 19 polymorphism locic concurrences with purple mutation. These results show that space flight could induce rice genome instability. The point mutation was mainly occurred on non-coding sequence. The purple mutation was the performance of rice genome instability. The purple mutation also exhibited genetic instability. Our findings may also have general implications in the molecular mechanism of space biology.