Work

High natural UVB radiation regulates grain pigmentation in black rice: insights from a genome-wide association study

Year: 2026

Type: article

Abstract: Black rice gains recognition in functional food and nutraceutical for its secondary metabolite profiles, which exhibit antioxidant, anti-diabetic, anti-hyperlipidaemic, and anti-cancer properties. Its unique purple-black colour trait results from anthocyanin accumulation in the pericarp, a trait that varies across pigmented genotypes. While the genetic basis of grain pigmentation in black rice has been partially elucidated, the influence of environmental factors, particularly ultraviolet (UV) radiation, remains poorly understood. UVB radiation is thought to play a role in regulating anthocyanin regulation in various crops, suggesting a potential advantage for cultivating black rice in high UV regions. This research aimed to identify quantitative trait loci (QTL) linking grain pigmentations in response to UV exposure. A genome-wide association study (GWAS) was performed on a diversity panel of 191 black rice accessions primarily sourced from the Asia-Pacific region. Utilising 31,501 single-nucleotide polymorphisms (SNPs), GWAS revealed distinct associations for anthocyanin content under UV conditions versus under non-UV conditions. Notably, three candidate genes associated with anthocyanin biosynthesis under UV exposure were identified: OsBBX14 , known to activate OsC1 or OsB2 in anthocyanin biosynthesis pathway; OsMYB44 , a transcription factor that promotes UV-B tolerance; and OsbZIP71 , which improves abiotic stress tolerance by reducing reactive oxygen species (ROS) accumulation. These findings provide critical insights into the genotype-by-environment interactions of grain pigmentation traits and pinpoint potential candidate genes for further validation and molecular marker development. Ultimately, this research supports the development of black rice varieties with enhanced nutritional value and improved resilience to high-UV growing conditions.

Source: Frontiers in Plant Science

DOI: 10.3389/fpls.2026.1943027

Authors: Truong Duc Nguyen, Manisha Thapa, Erwin Tandayu, Lei Liu, Szabolcs Lehoczki-Krsjak, Tobias Kretzschmar

Institutions: Southern Cross University, Agriculture Victoria

Language: English

Topic: Genetic Mapping and Diversity in Plants and Animals

Subfield: Genetics

Field: Biochemistry, Genetics and Molecular Biology

Domain: Life Sciences

SDG: Zero hunger

Open Access status: gold

Estimated APC paid: $3,801