Mutant petunias singing the blues

Blue petunias are a rarity in nature and a favorite among gardeners. Now, researchers say they have discovered the genetic glitch that produces the colored flowers.

In healthy petunias, a previously undiscovered “cellular pump” delivers high quantities of acid to special compartments in plant cells known as vacuoles. Composed of just two proteins working together, the pump is capable of delivering acid to a vacuole long after other pumps would stop, producing a highly acidic flower with a bright red-violet color.

But some petunias contain a mutation in the genes that carry the code for that pump, leaving it disabled. As a result, the petals don’t become very acidic and turn blue instead of red. The study was published in the journal Cell Reports.

For petunias, blue petals represent an evolutionary disadvantage because they do not attract the insects that provide pollination.

“In the survival of the fittest contest, petunia flowers with blue colors will get lost,” said Francesca Quattrocchio, a biologist at VU University Amsterdam in the Netherlands and an author of the study.

Today, most blue petunias are produced by breeders. The study’s findings could be used to manipulate the taste and color of other plants and fruits, she said.

Females favor a familiar fish face

Female fish are quicker to mate with a male they’ve seen before, thanks in part to a neuron that springs to life in the presence of familiar males, researchers say.

Looking to better understand the neural underpinnings of social decision making, Japanese scientists monitored the nervous systems of female medaka fish as they were introduced to males through a glass partition, then later placed in a tank with those same males to mate.

Females paired with familiar males consented to mating with them much faster than females that were paired with strangers. One reason for this, say the researchers, is that a neuron called TN-GnRH3 became active in the females when they saw the familiar male, releasing peptides into the brain that made the female more receptive to mating. Normally, the neuron is barely active, curbing the female’s interest in unfamiliar males.

Social familiarity is known to influence mating decisions in many species of animals, but there is still much to be learned about the neural activity accompanying such decisions, said Hideaki Takeuchi, a biologist at the University of Tokyo and an author of the study, published in Science.

“To date, the social brain has been studied mainly in humans,” Takeuchi said. “Recent studies of animal behaviors, however, suggest that fish, the most primitive vertebrate, also have a social brain.”

– New York Times