Spectrum and Density of Gamma and X-ray Induced Mutations in a Non-Model Rice Cultivar

Area of Science:

• Plant genetics
• Radiation mutagenesis
• Genomics

Background:

• Physical mutagens have been used in genetic research and crop breeding for decades.
• Limited data exists on the mutation spectrum and density induced by different physical mutagens and dosages compared to chemical mutagens.
• Understanding induced mutation landscapes is crucial for advancing functional genomics and crop improvement strategies.

Purpose of the Study:

• To investigate the mutation spectrum and density induced by gamma and X-ray radiation in rice (Oryza sativa L.).
• To evaluate the impact of varying radiation dosages on mutation patterns.
• To provide insights into mutagenesis for functional genomics and breeding applications.

Main Methods:

• Generation and propagation of a rice mutant population over seven generations.
• Application of five distinct dosages (75 Gy to 600 Gy) of both X-ray and gamma radiation.
• Whole-genome sequencing of 11 selected mutant lines exhibiting phenotypic variation.
• Analysis of mutation types, including single base substitutions, small indels, and structural variants.

Main Results:

• Thousands of candidate mutations were identified in each mutant line.
• Single base substitutions were the most prevalent mutation type, followed by small indels and structural variants.
• Higher radiation dosages increased mutation accumulation in gamma-irradiated rice, but this effect was not observed in X-ray-treated plants.

Conclusions:

• Gamma and X-ray radiation effectively induce a high density of mutations, including single nucleotide and structural variants, in rice.
• Radiation dosage impacts mutation accumulation differently between gamma and X-ray treatments.
• Mutagenesis remains a vital approach for functional genomics and the development of improved crop varieties.