Distinct molecular pathways control plant growth and flowering

It is well known that plants have a precise ability to detect seasonal changes based on the amount of daylight they are exposed to. Yet scientists observed more than a century ago that plants sometimes grow in one season and flower in another. However, most research in subsequent decades focused on seasonal flowering, leaving this classic observation unstudied.

In a new study, a Yale-led research team revisits this idea that growth and flowering sometimes occur in different seasons, asking whether these two phenomena might therefore be controlled by distinct molecular mechanisms within plants.

The answer is yes, they reported on February 9 in the newspaper. Science.

Previously, researchers had identified a specific genetic mutation that can hinder flowering, a discovery that allowed scientists to track in detail the molecular changes triggered by day length, and thus allow plants to flower.

In the new study, researchers discovered specific genetic mutations that suppress growth, but do not affect the plant’s ability to flower. The study was led by Joshua Gendron, associate professor of molecular, cellular, and developmental biology in the Yale School of Arts and Sciences, and first author Qingqing Wang, a postdoctoral associate in Gendron’s research lab.

They then discovered that the molecular pathways that control flowering and growth are distinct.

Plants produce flowers based on the amount of light they detect through photoreceptors, similar to those found in our eyes. However, according to researchers, seasonal growth is determined by the length of time photosynthesis actively occurs each day.

“We were surprised to find that plants can experience a flowering season and a growing season in a single natural day,” Gendron said. “They are completely separate from each other, which means the plants experience two seasons simultaneously.”

In agricultural production, it is essential to understand when a plant will grow and flower. These new findings provide a potential avenue for using genetics to modify the seasonal growth of important crop species.

“One of the other important benefits comes from the ability to maximize the growth of species grown in greenhouses through controlled lighting,” Gendron said. “Currently, energy consumption (related to these agricultural operations) limits the growth of many greenhouse crops.”