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

Abstract

Physical mutagens are a powerful tool used for genetic research and breeding for over eight decades. Yet, when compared to chemical mutagens, data sets on the effect of different mutagens and dosages on the spectrum and density of induced mutations remain lacking. To address this, we investigated the landscape of mutations induced by gamma and X-ray radiation in the most widely cultivated crop species: rice. A mutant population of a tropical upland rice, Oryza sativa L., was generated and propagated via self-fertilization for seven generations. Five dosages ranging from 75 Gy to 600 Gy in both X-ray and gamma-irradiated material were applied. In the process of a forward genetic screens, 11 unique rice mutant lines showing phenotypic variation were selected for mutation analysis via whole-genome sequencing. Thousands of candidate mutations were recovered in each mutant with single base substitutions being the most common, followed by small indels and structural variants. Higher dosages resulted in a higher accumulation of mutations in gamma-irradiated material, but not in X-ray-treated plants. The in vivo role of all annotated rice genes is yet to be directly investigated. The ability to induce a high density of single nucleotide and structural variants through mutagenesis will likely remain an important approach for functional genomics and breeding.

Application of SNP Markers to Identify Genetic Variation on Mutant Lines of Adan-Krayan, Special Local Rice from North Kalimantan

“…3 illustrates examples of alleles displaying mutations in each mutant, focusing on chromosome 1, which exhibits the highest mutation incidence compared to other chromosomes. A similar incident also happened in the research of Jankowicz-Cieslak et al [30], where whole genome sequencing was used to detect the effects of mutations in rice. The results showed that eleven mutants had altered genomic composition.…”

Effect of X-rays on Seedling Pigment, Biochemical Profile, and Molecular Variability in Astrophytum spp.

“…Inducing mutations into genes with ionizing radiation is a well-known method of increasing genetic diversity in crop breeding. X-rays have proven effective in inducing phenotypic changes in many ornamental plant species, including achimenes, alstroemeria, azalea, begonia, bougainvillea, chrysanthemum, dahlia, carnation, hibiscus, lily, calla, rose, and tulip [11,[43][44][45][46][47][48][49][50]. However, the literature lacks studies on the effect of ionizing radiation on cacti.…”

Mutagenesis in the Age of Next-Generation-Sequencing and Genome Editing

“…Physical mutagens, such as gamma and X-rays, have been important mutagens for mutation breeding for over 80 years; however, the spectrum of mutations induced by these mutagens is not well understood. Jankowicz-Cieslak et al revealed the spectrum of mutations induced by gamma-and X-ray in rice using next-generation sequencing [14]. Hudson demonstrated that induced mutation by N-methyl nitrosourea (NMU) is an effective approach to improve protein and oil content in soybean [15].…”