Nanoparticles help rice overcome the trade-off between yield and quality

Rice is a staple food for more than half the world, but making it more productive, nutritious and palatable at the same time remains a challenge. A new study in Model Organisms Research suggests that zinc oxide nanoparticles could help direct-seeded rice do all three.

The study compared foliar application of zinc oxide nanoparticles with conventional zinc sulphate in direct-seeded rice, a cultivation method increasingly used to reduce labour and water requirements. While direct seeding offers practical advantages, it can also affect nutrient uptake, grain filling and cooking quality.

“Across two field trials in China, we found that zinc oxide nanoparticles outperformed conventional zinc treatment in key agronomic, nutritional and quality traits,” shares senior and co-corresponding author Shiquan Bian. “Compared with untreated rice, the nanoparticle treatment increased zinc concentration in polished rice by 25.6%, spikelets per panicle by 12.4% and 1000-grain weight by 4.8%. It also reduced amylose content and chalkiness, traits associated with improved cooking and eating quality.”

Further physiological and transcriptomic analyses showed that they altered antioxidant activity, plant hormone balance and starch metabolism during grain development. “The treatment increased levels of zeatin and gibberellin A₃, boosted antioxidant enzymes and reduced oxidative damage. It also activated starch-remodelling genes, including OsAmy1C and OsRAmy1A, while suppressing OsCKX2, a gene involved in cytokinin breakdown,” says Bian.

These changes point to a nano-specific effect that was not observed with zinc sulphate. “Rather than simply fertilising the crop, the nanoparticles appeared to help regulate the biological processes that determine how rice grains fill, store starch and develop quality traits,” adds Bian.

The team's findings suggest that carefully applied zinc oxide nanoparticles could offer a non-GM strategy for improving rice yield, grain zinc biofortification and cooking quality. “Nonetheless, further validation will be needed to assess long-term field performance and environmental safety, but the study provides molecular evidence for a more precise approach to sustainable rice production,” notes Bian.

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Contact author: Shiquan Bian.  Rice Research Institute, Anhui Academy of Agricultural Sciences, Hefei, 230031, P.R. China. Email address: bianshiquan@aaas.org.cn

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