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Insights into Rice Evolution from Groundbreaking Study
A recent study published in Nature Genetics, conducted by researchers at King Abdullah University of Science and Technology (KAUST) in Saudi Arabia and Wageningen University & Research in the Netherlands, sheds new light on the evolutionary journey of rice. This research is anticipated to enhance rice yields and facilitate its cultivation in regions where growing this staple crop is currently challenging.
Rice, believed to be one of the earliest domesticated crops, was first cultivated around 10,000 years ago. Throughout history, selective breeding by farmers has emphasized traits that improve nutritional value and profitability, resulting in diminished genetic diversity. This loss of diversity has made the crop more vulnerable to various environmental stressors.
In contrast, the wild relatives of rice, classified under the genus Oryza, have evolved over approximately 15 million years, leading to significant genetic variation. This diversity equips these wild relatives with a greater capacity to adapt to diverse environmental challenges, including heat, drought, and salinity.
Professor Rod Wing from KAUST, who spearheaded the study alongside postdoctoral research associate Alice Fornasiero, commented, “The genus Oryza encompasses a remarkably rich genomic portfolio. Our findings elucidate the implications of evolutionary changes on the collective genomes of rice and its wild counterparts.”
While humans are diploid (inheriting two chromosome sets from each parent), many plants, including rice, can be polyploid, meaning they can inherit multiple sets of chromosomes. This condition often results in larger genomes, enhancing a plant’s adaptability to new or challenging environments and driving the evolution of novel traits.
The research analyzed nine tetraploid and two diploid species within the Oryza genus. The scientists discovered distinct genome subsets enabling species differentiation, primarily driven by transposable elements, colloquially known as “jumping genes.” These elements are DNA sequences capable of moving within the genome, contributing to natural genetic diversity.
The presence of both diploid and tetraploid species resulted in genome sizes differing by more than double. Embedded within this extensive DNA are genes that bolster the rice plant’s resilience against rising temperatures, drought, high salinity, and other environmental challenges that are becoming prevalent in the Middle East and worldwide due to climate change.
The research also mapped the evolutionary tree of wild rice, identifying periods when new species emerged, providing insights into significant stress events that may have prompted genomic adaptations for survival.
Professor Eric Schranz from Wageningen University, a co-author of the study, stated, “This genome analysis offers a thorough understanding of the evolutionary trajectories of rice and its intricate wild relatives. It lays a robust foundational framework for future initiatives aimed at developing resilient rice varieties that can thrive in harsh conditions.”
With over 3.5 billion people depending on rice as their primary food source, its significance as a vital global crop cannot be overstated.
More information: Alice Fornasiero et al, Oryza genome evolution through a tetraploid lens, Nature Genetics (2025). DOI: 10.1038/s41588-025-02183-5
Source
phys.org