The Genetic Basis Of Strawberry Aroma

Researchers at CRAG have identified the FvHI gene as a key player in regulating the compounds responsible for the fresh aroma of strawberries, demonstrating that its activity modulates the balance between volatile molecules that determine the fruit’s fragrance.

• CRAG researchers have identified the FvHI gene, which regulates the balance between key volatile compounds that define the fresh and characteristic aroma of strawberries.
• The study shows that FvHI expression controls the balance between two key aromatic molecules, using wild strawberry as a model to overcome the genetic complexity of cultivated strawberries.
• This discovery paves the way for developing strawberry varieties with improved aroma and greater resilience to damage, wounds, and certain pathogens, leveraging natural compounds involved in both fruit sensory quality and plant defences.

Aroma is one of the most appreciated attributes of strawberries, but also one of the most complex: it depends on a combination of sugars, acidity, texture, and especially volatile compounds responsible for its characteristic fragrance. Among these, green leaf volatiles (GLVs) stand out, providing the fresh and slightly herbaceous notes typical of the most aromatic strawberries.

Two molecules play a fundamental role in this feature: (Z)-3-hexenal, associated with “greener” notes, and (E)-2-hexenal, linked to fresher and sweeter sensations. Until now, it was unknown which gene controlled the conversion between these compounds, a chemical change that modulates the fruit’s final aroma. The work, carried out by CRAG researchers Rong Zhang, Dylan Nunnally, and Elli Koskella, and led by Amparo Monfort, IRTA researcher at CRAG, has been published in Horticulture Research. The study focused on deciphering the mechanism that controls the balance between these two crucial aromatic molecules and how this can help develop new varieties.

The FvHI gene: an aroma regulator
Researchers demonstrated that differences in strawberry aroma profiles are due to how the FvHI gene is regulated, not to significant changes in the protein it encodes: when FvHI expression is low, (Z)-3-hexenal increases, intensifying green notes, while its overexpression boosts (E)-2-hexenal, enhancing a sweeter aroma. This discovery confirms that FvHI acts as a key molecular regulator defining the characteristic smell and taste of strawberries.

A “fruitful” approach: the importance of the wild model
To unravel the mechanisms shaping strawberry aroma, researchers worked with nearly isogenic lines (NILs), which are genetically very similar except for a specific genomic region. These NILs were developed from a cross between diploid strawberry species, allowing the gene responsible for aroma to be pinpointed and its function validated.

“This approach is especially useful because cultivated strawberry (Fragaria × ananassa) is an octoploid crop, meaning it has eight sets of chromosomes, which makes its genetics very complex and complicates the study of aroma-related genes. In contrast, its wild relative Fragaria vesca, a diploid species and research model, shares much of its genome with commercial strawberry and has a simpler genetic architecture” said Amparo Monfort, lead author of the study.

Beyond aroma, the compounds involved in this process, green leaf volatiles (GLVs), also participate in the plant’s response to damage and wounds. Understanding how these compounds are regulated not only improves fruit sensory quality but also opens the door to enhancing crop resilience and natural protection.

Implications for the future of strawberries
The results of this research provide new tools to guide the improvement of strawberry varieties with flavours more appreciated by consumers, since aroma is a fundamental component of taste along with the balance of sugars and acids. This lays the foundation for developing new strawberry varieties with fresher and more balanced aromatic profiles.

But its relevance goes beyond sensory quality: GLVs involved in this process play an essential role in the plant’s natural defence mechanisms against damage and wounds. Therefore, this advance not only promotes the development of fruits with better aroma but also opens the door to more resilient crops that are less dependent on chemical treatments, favouring breeding strategies that combine fruit quality and agricultural sustainability.