The recent development of genome editing technologies using CRISPR/Cas9 has marked a new era in precise genome editing. This study reports on genome editing using seven single-guide RNAs (sgRNAs) to target different positions in the OsGTL1 promoter in rice (Oryza sativa L.). This research focused on identifying CRISPR-edited plants before evaluating the effects of OsGTL1 modification in rice progeny. We successfully developed gene-edited lines that have different types of mutations. Moreover, our study detected at least 35% of genetic chimerism in the first generations of the edited lines. This chimerism resulted in a mosaic of genotypes within an individual plant, suggesting multiple CRISPR-Cas9 events targeting the target region. We successfully identified transgene-free lines in later generations. Various modifications occurred in the targeted region, including large and small deletions, single-base insertions and deletions, and inversions. This study highlights the complex challenges and opportunities of applying CRISPR/Cas9 to improve rice traits, emphasizing the importance of detailed characterization of edited lines to fully understand a gene's function and its pleiotropic effects.

This research attempted to validate novel molecular markers linked to high antioxidant traits using an F₂ population and a local Thai rice population. We performed total flavonoid content, total phenolic content (TPC), and ferric reducing antioxidant power (FRAP) assays to assess the antioxidant capacities of rice populations. In the F₂ (“Pathum Thani 1”דHawm Mali Daeng”) population, these traits exhibited a quantitative distribution with high heritability (82.7%–98.3%) and high genetic advance (66%–94%). In validation using 10 molecular markers, OsRc and In1-Rc displayed polymorphism in parent cultivars and in bulked segregant analysis. However, only OsRc had strong associations with TPC (R² = 52.2%, p < 0.001) and FRAP (R² = 43.0%, p < 0.001), whereas In1-Rc featured no significant associations (R² ≤ 0.1%). When verified in Thai rice cultivars, OsRc could discriminate red pericarp rice cultivars with high antioxidant properties from white pericarp cultivars with low antioxidant activity, confirming its efficiency in selecting antioxidant traits in rice. These findings indicate that OsRc is a functional marker for selecting rice lines with high antioxidant activity, thereby facilitating early-stage genotyping in rice breeding programs.

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• Genome-wide association study of antioxidant compounds and antioxidant activity in a panel of Thai rice cultivars
  Saranyu Thaworn, Phanomsak Tomjai, Teerapong Buaboocha, Supachitra Chadchawan, Monnat Pongpanich, Chanita Paliyavuth, Waraluk Kasettranan
  Euphytica.2026;[Epub]     CrossRef