Better wine through
better yeast hybrids

Courtesy of Flickr/Creative Commons user Alex Brown

If you enjoy a perfectly chilled glass of sauvignon blanc or a rich merlot, you can thank heterosis. Heterosis occurs when an offspring has increased vigor or superior biological qualities compared with its parents. In a recent Molecular & Cellular Proteomics paper, researchers analyzed the molecular basis for heterosis in yeast, microorganisms on which the entire wine industry relies.

Plant and animal breeders have capitalized on heterosis for a long time when crossbreeding to create hybrids with desirable traits. But according to Michel Zivy, corresponding author of the MCP paper and a researcher at the National Center for Scientific Research in France, understanding and using heterosis more efficiently “is one of the bigger challenges in plant genetics and breeding.” He adds that understanding the molecular mechanisms is essential to predict heterosis reliably. Currently, there is no single unifying way to predict it.

Zivy and colleagues used a novel approach to understand better the underlying factors augmenting heterosis. The investigators used yeast because the microorganisms are “less complex than other systems like plants,” says Zivy. Also, hybrids of common brewer’s yeast, such as hybrids between Saccharomyces cerevisiae and S. uvarum, are known to be better at wine-making than their parents. In addition, using high-throughput proteomics allowed the researchers to analyze in a fast and automated way how heterosis affected the abundance of more than 1,300 proteins from the yeast strains used.

The researchers grew all the yeast strains in the same batch of freshly squeezed white grape juice at two different temperatures, because temperature can influence yeast growth and metabolism. Once fermentation was complete, they extracted the proteins from the yeast samples and quantified them.

The investigators showed that offspring born of parents of different species showed stronger heterosis than those born of parents of the same species. They also showed that heterosis depends on the functional category of the protein. For example, the proteins involved in response to environmental changes — such as energy and virulence — showed more heterosis.

Zivy hopes to improve the experimental method that the team used so that it can be applied to more complex systems, such as crops. And wine lovers, rejoice: Zivy and colleagues, one of whom works for the wine research company Laffort, now are using their newly found knowledge of the yeast proteome and heterosis to create better yeast hybrid strains for more aromatic wines.

Soma Chowdhury Soma Chowdhury is an intern at ASBMB Today. She also interns with NIH’s intramural research magazine NIH Catalyst.