The achievement was the result of a joint international study, including the research arm of Suntory and research institutions from Japan and the Czech Republic.
The research found that the EXER gene was critical in determining sex on hops plants, such as Humulus lupulus, which is essential for brewing beer.
Unlike many plant species with both male and female reproductive organ, hops have male and female reproductive organs in separate plants.
It requires both requires both male and female plants to reproduce, but only the female hops flowers are used to brew beer.
The findings are expected to speed up the development of new hop varieties with better flavour, aroma, and growth traits, said Suntory.
The study, which was published in Nature Plants on June 18, found that when the EXER gene is expressed, it promotes the growth of female reproductive parts while hindering the growth of male parts.
When the gene is repressed, it promotes the growth male reproductive parts.
“The contrasting results confirmed that the sex of hops and other dioecious plants in the Cannabaceae family is determined by EXER,” said the researchers.
Methods and findings
This study was based on previous understanding on the X-A balance system in the sex determination of hops.
In 2014, research led by Suntory published a near-complete DNA sequence of female hops.
However, the team could not fully explain how sex was determined, as the technology was not advanced enough yet.
For this research, they utilised an advanced genome sequencing techniques to determine the genome sequences of a female and male hop.
From this, they constructed high-quality genome sequences assembled at the chromosome level.
To identify sex-determining genes in the X-A balance system, the team also conducted a comparison of the X and Y chromosomes of both hops.
This study also revealed the genome of the male Humulus japonicus, a wild relative of hops, which provided helpful comparative data.
According to the study the EXER gene was found in all the X chromosomes of dioecious plants within the Cannabaceae family, which also includes plants like cannabis.
This helped to confirm the EXER as the sex determinant gene across the family.
These findings are also expected to advance the understanding of sex determination across other organisms.
Source: Nature Plants
Evolution and functioning of an X-A balance sex-determining system in hops” on the website of the world-renowned scientific journal
Authors: Akagi, T., Segawa, T., Uchida, R. et al.
https://doi.org/10.1038/s41477-025-02017-6