Tea is one of the most popular drinks in the world, but the size of the young buds at the top of the tea plant plays an enormous role in how tea tastes and how much of it can be harvested. Larger buds often increase the amount of tea leaves produced, while certain high-quality teas require very specific bud-to-leaf ratios.
Despite the importance of bud size, scientists have long struggled to pinpoint the genes that control how big tea buds grow. Without this knowledge, breeding new tea varieties has been slow and challenging.
A new study from the Tea Research Institute of the Chinese Academy of Agricultural Sciences brings major progress. The research, published in *Horticulture Research*, has identified a single gene—called **CsKNOX6**—that appears to play a powerful role in limiting the size of tea buds. This discovery opens new possibilities for developing tea plants that can produce better flavor, higher yields, and improved consistency.
To uncover this gene, the research team studied 280 different tea plant varieties. Using digital imaging, they measured bud length, width, area, and other traits, discovering that these characteristics differ widely between varieties but are strongly controlled by genetics. They then used genome-wide association analysis to search for genetic differences connected to bud size.
Their data pointed strongly to four possible genes in the Class I KNOX family—genes known to affect shoot growth in plants. Among these, **CsKNOX6** stood out. It was found more often in small-bud varieties and showed higher activity in these plants. Its location on Chromosome 10 and predicted role as a transcription factor suggested that it acts as a growth regulator.
To confirm this, the researchers tested CsKNOX6 in *Arabidopsis thaliana*, a common model plant often used in genetics research. When they overexpressed the gene—meaning they made the plant produce more of it—the plants developed much smaller leaves. In severe cases, leaf size dropped to just 13% of normal levels. This provided strong evidence that CsKNOX6 is a negative regulator of plant organ growth.
The researchers note that controlling bud size is important for both tea farming and tea quality. For example, premium hand-picked teas depend on delicate buds of specific sizes, while commercial mechanical harvesting benefits from larger, uniform buds. Identifying CsKNOX6 gives breeders a specific genetic tool that can be targeted through marker-assisted breeding or even future gene-editing techniques.
While the *Arabidopsis* tests were successful, the next step is to validate the gene directly in tea plants. Because tea is a perennial woody species, translating findings from model plants to real tea crops is complex but essential.
This discovery moves tea science into a new era of precision breeding. By better understanding how bud size is controlled at the genetic level, scientists can help create tea varieties that meet the needs of farmers, processors, and consumers—ultimately improving both the quality and economic value of one of the world’s favorite beverages.
https://knowridge.com/2025/11/scientists-discover-a-key-gene-that-helps-shape-the-taste-and-quality-of-tea/
