Hops Sex Gene Discovery: Suntory Breeding Advance
Scientists Identify Gene Controlling Sex in Hops, Paving Way for Better Beer
Table of Contents
Unlocking the Secrets of Hop Reproduction
researchers have pinpointed a gene, dubbed EXER, that determines the sex of hop plants – a crucial breakthrough with important implications for the brewing industry. The discovery, published in Nature Plants on June 18th, promises to accelerate the progress of new hop varieties boasting improved flavour, aroma, and growth characteristics. Hops, essential for beer production, are unique in that only the flowers from female plants are used in brewing.
The Role of EXER in Sex Determination
Hop plants are dioecious, meaning they require both male and female plants for reproduction. However, brewers rely solely on the female plants for their distinctive bittering, flavouring, and aromatic qualities. Understanding the genetic mechanisms controlling sex in hops has long been a challenge. This new research reveals that the EXER gene plays a pivotal role in this process.
When the EXER gene is actively expressed, it encourages the development of female reproductive structures while concurrently suppressing the growth of male parts. Conversely, when the gene is repressed, male reproductive parts are favoured. The researchers definitively confirmed that EXER is the key determinant of sex not only in hops, but also in other dioecious plants within the Cannabaceae family, including cannabis.
Methods Behind the Discovery: Advanced Genome Sequencing
The breakthrough builds upon previous work by Suntory researchers,who in 2014 published a near-complete DNA sequence of female hops. While that research provided a foundation, the technology at the time wasn’t advanced enough to fully unravel the complexities of sex determination.
This latest study leveraged cutting-edge genome sequencing techniques to meticulously map the genomes of both female and male hop plants. This resulted in high-quality genome sequences assembled at the chromosome level, allowing for a detailed comparison of the X and Y chromosomes.
Crucially, the team also analyzed the genome of Humulus japonicus, a wild relative of hops, providing valuable comparative data. This comparative analysis, combined with the X-A balance system understanding, allowed them to pinpoint EXER as the critical gene. The X-A balance system refers to the ratio of X chromosomes to autosomes (non-sex chromosomes) influencing sex determination.
Implications for the Brewing Industry and Beyond
The identification of EXER opens exciting possibilities for hop breeders. by manipulating the expression of this gene, scientists can potentially develop new hop varieties with a higher proportion of female plants, streamlining production and enhancing desirable traits. This could lead to beers with more intense aromas, unique flavour profiles, and improved hop yields.
Furthermore, the findings extend beyond the realm of brewing. The EXER gene’s presence and function within the Cannabaceae family - which includes cannabis - suggests a shared genetic mechanism for sex determination. This discovery could also contribute to a broader understanding of sex determination processes across a wider range of plant and animal species.Source: Nature Plants
Evolution and functioning of an X-A balance sex-determining system in hops”
Authors: akagi,T., Segawa, T., Uchida, R. et al.
https://doi.org/10.1038/s41477-025-02017-6