Molecular characteristics of rice chimeras containing gene mutations induced by carbon ion beam radiation

Abstract

Chimeras are universal phenomena in the M1-generation plants obtained following radiation-induced mutagenesis; however, the mutational effects and variant inheritance mechanisms of related rice chimeras have yet to be sufficiently clarified. In this study, we used target capture-seq technology to obtain OsNramp5 mutant chimeras via carbon ion beam irradiation, and used a 10 kb liquid chip to determine the SNP/InDel mutational occurrence and genetic isolation characteristics of the chimeric M1 generation and mutational M2 genomes. The results revealed that the mutation detected in the OsNramp5 gene of M1 chimeric rice was not inherited by the M2 generation; that is, the mutation detected in somatic cells of the M1 population was not passed to the subsequent generation via the germ cells. In addition, conversion was established to be twice as common as transversion among the M1 genomic mutation types, although more than half of the variant sites were inherited by the M2 generation. However, these sites were rarely located within the functional coding regions of genes. Our findings in this study revealed the genomic variation characteristics of somatic M1-generation chimeras induced by carbon ion beam irradiation and their genetic characteristics in the M2 generation. These findings will provide a reference for further studies that seek to elucidate the mechanisms underlying chimeric mutation effects and for selecting appropriate procedures for mutagenesis breeding following carbon ion beam irradiation.

Keywords

• carbon ion beam
• irradiation mutagenesis
• gene mutation
• chimera
• heritable variation