Yeast used in beer brewing gives off its signature scent to attract flies, which disperse the cells throughout the environment.
When this yeast lacks even one aroma gene they no longer produce the scent, and also fail to attract the flies, Cell Press reported.
"Two seemingly unrelated species, yeasts and flies, have developed an intricate symbiosis based on smell," said Kevin Verstrepen of KU Leuven and VIB in Belgium. "The flies can feed on the yeasts, and the yeasts benefit from the movement of the flies."
The researchers were studying how yeast contributed to the taste of beer and wine. They found yeast could produce several pleasant aromas similar to ripening fruit. The team traced this phenomenon back to the yeast gene ATF1 for alcohol acetyl transferase.The researchers first noticed this phenomenon by accident.
"When returning to the lab after a weekend, I found that a flask with a smelly yeast culture was infested by fruit flies that had escaped from a neighboring genetics lab, whereas another flask that contained a mutant yeast strain in which the aroma gene was deleted did not contain any flies," Verstrepen said.
The researchers teamed up with fruit fly neurobiologists Emre Yaksi and Bassem Hassan a year after the intial discovery, and used a combination of molecular biology, neurobiology and behavioral tests, to take a closer look.
The team found ATF1 causes flies to be less attracted to mutant yeast cells, leading to a reduced dispersal of these genes.
The findings provide insight into an aroma-based communication process between microbes and insects that could exist in other relationships as well. The researchers have already isolated different yeast species from the body of fruit flies and found many produce unique aromas. They have also pinpointed these aroma-producing yeasts in flowers.
"These preliminary results suggest that aroma production is not restricted to S. cerevisiae and may be a much more general theme in microbe-insect interactions," the researchers wrote.
The findings were published in a recent edition of the journal Cell Reports.
