Variation in RNA-editing sites of chloroplast protein-coding genes in early-maturity mutant induced by carbon-ion beam in Sweet Sorghum

Using prediction and experimental determination, we compared the RNA-editing sites in chloroplast protein-coding genes in an early-maturity mutant (KFJT-1) induced by carbon-ion beam irradiation in sweet sorghum and its wild type (KFJT-CK). Twenty-two and 20 editing sites were identified in the KFJT-CK and KFJT-1 chloroplast, respectively, and the differential editing sites between KFJT-CK and KFJT-1 were mainly in mat, ndh and rpo genes. Furthermore, mutations in RNA-editing sites in KFJT-1 affected the structure of the encoded protein, which implying that RNA-editing events might influence the function of essential genes. Finally, a comparative analysis of the RNA-editing events between KFJT-1 and other 10 Poaceae species revealed that the RNA-editing sites in matK-1002, rpoC1-1163 and rpoC2-242 were unique to KFJT-1. This suggested that RNA-editing events due to carbon-ion beam irradiation affected the structure of the encode proteins, thereby influenced their biological functions. This study is the first to report on the variation in chloroplast RNA-editing patterns induced by carbon-ion beams irradiation, and its effect on the chloroplast in KFJT-1 at the post-transcriptional level.