Multitasking genes manage related traits in plants

Think of it as finding the ultimate genetic engineers.

A plant biologist at Michigan State University has harvested clues about genes that coordinate the development of plant parts that must work together.

The work, published in the Nov. 28 issue of the British science journal Nature, points to a single mechanism that regulates the growth of related parts in flowers – kind of a genetic project manager.

“This is why we’re not just a discombobulated collection of parts. We’re coordinated,” said paper author Jeffrey Conner, an associate professor of plant biology. “I found that the same genes can affect pairs of related traits.”

Scientists have understood that creatures evolve to optimize their ability to survive and reproduce, ultimately building a plant or animal better adapted to its environment.

In plants, this can be seen in the size and proportions of a flower. Flowers are serious business in the plant world, the ground zero of reproduction. The parts of a flower – the petal, stamen and pistil – must be precisely constructed to lure a pollinator in to both fertilize the plant and carry away genetic material in the pollen to other flowers.

If a flower’s tube – where the nectar is – was short in relation to its stamens, the male parts of the flower, a bee could dive in, nab nectar and leave without rubbing up against the anthers and picking up their pollen.

“A flower has to evolve to successfully manipulate the behavior of the animal that pollinates it to get what it needs,” Conner said. “The key is to make contact with the anthers and stigma. If that doesn’t happen, it’s worthless, from the plant’s point of view.”

Conner, who does his National Science Foundation–funded research at MSU’s Kellogg Biological Station, spent years randomly crossbreeding generations of wild radish to understand how the plant coordinates its floral parts to best reproduce.

He found that consistently the plant would evolve to make sure the flower’s tube and stamen parts developed in tight correlation, and that this development was traced to a number of genes doing double duty.

This genetic mechanism creates a design stability that carries the organism successfully through evolution.

While Conner works on plants, he said this tight orchestration is seen in all organisms. Genetic coordination, for instance, is the reason human arms don’t grow out of concert with legs and send people’s knuckles dragging to the ground.

“It keeps the parts in the right proportion, so they can do a job,” he said.

Understanding that a single gene affects more than one part can help reveal why plants are successful and how they maintain a structural stability over time.

It also, Conner said, opens new areas of study in all organisms about the role one gene, or group of genes, can play.

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