On May 23rd, Hainan University announced that its Tropical Crop Metabolic Biology Research Team from Sanya Nanfan Research Institute has successfully cultivated “Tea Rice”, which is enriched with catechins in the endosperm.  This offers a novel approach to the development of functional grain. The findings were recently published in the Plant Biotechnology Journal.

Catechins, a subclass of flavan-3-ols, constitute the primary polyphenols constituents of tea plant, contributing to human health through their antioxidative, anti-inflammatory and cardioprotective properties. However, some individuals are unable to acquire Catechins through tea consumption, for they are very sensitive to caffeine (theophylline) in tea.

Rice, a major staple crops worldwide, has low expression or non-functionality of flavonoid pathway genes, which results in scarce flavonoid content in the endosperm. Even in pigmented rice, flavonoids mainly exist in the pericarp, and they are rarely found in polished rice (endosperm).

Professor Luo Jie, the team leader, explains that polished rice (endosperm) naturally lacks catechins but exhibits robust bioactivity. Building on its bioactivity, the team has developed a tissue-specific metabolic engineering approach for rice modification. By harnessing enzymes involved in the catechin biosynthetic pathways, they have created a functional “Tea Rice” with a high content of catechins in the endosperm. Specifically, the team has successfully constructed a catechin biosynthesis pathway in rice endosperm through genetic editing engineering and endosperm-specific expression technology, combining the key functional genes of tea plant and other exogenous plant genes with rice endosperm.

The experimental results show that the gene-modified rice endosperm contains various components, including epicatechins and catechins, exhibiting significantly enhanced antioxidant capabilities compared to the control variety.

It’s reported that this study made groundbreaking progress in solving the technological bottleneck of flavonoid accumulation in rice endosperm. Not only does it provide a practical model for the development of “catechin-fortified” functional cereals, but it also offers a universal technical strategy for the targeted synthesis of other high-value natural products such as carotenoids and phytosterols in crops.

English Translator: Li Yang

Proofread by Zhu Yan