Plants’ Unlikely Defense Against Climate Change: Different Leaf Structures

When it comes to plant leaf diversity, it’s not just for show, according to a new University of Maryland study that identified a genetic mechanism responsible for variations in leaf structure. These differing shapes play a crucial role in how plants adapt to different environments.

For instance, strawberry leaves with more serrations mean the plants will have higher resilience during cold temperatures, while broader, smoother leaves mean they’ll do better in warmer climates. “Morphological differences contribute to plant survival, including how well plants can regulate their temperatures and how efficiently they can transport water from their roots to the rest of their bodies,” said Zhongchi Liu, a professor emerita in the Department of Cell Biology and Molecular Genetics. “Understanding the mechanisms responsible for diverse leaf forms will lead to a better understanding of how plants can survive challenging conditions.”

In a paper published last month in the journal Current Biology, Liu’s lab identified two key regulatory pathways involved in the development of leaves on three types of strawberry plants with different leaf structures.

One is led by genes expressing each plant’s distinct leaf complexity—single piece vs. multiple leaflets—while another regulates so-called margin features, or whether leaves have smooth or serrated edges. The researchers found the two pathways took turns shaping the development of leaves over time, and say this connection between the timing and the resulting leaf structures could be used to help plants adapt to or tolerate a greater range of conditions and environments, including greater resistance to climate change, according to the researchers.

“If we can tune that relationship, we can do things like have the strawberries produce a larger biomass, potentially supporting more fruit production,” said Xi Luo, the paper’s lead author and a postdoctoral associate in cell biology and molecular genetics. “We can also take these strawberries somewhere beyond their native habitat and expand their adaptivity by changing their leaf morphologies.”

Other UMD co-authors of the paper include postdoctoral associate Lei Guo and Ethan Tagliere ’23.

Liu’s team found that the two pathways impacted the strawberry plants at different stages of development. For example, the pathway ruled by the gene that expresses leaf complexity can dictate that a strawberry plant develops single-leaf formations rather than its usual trifoliate (three-piece) growth pattern. As the plant matures, the pathway ruled by the gene that expresses margin feature can inhibit a gene known as CUC2 to limit how deep the leaf serrations are. As a strawberry plant grows, the pathways work together to activate or inhibit the CUC2 gene resulting in diversely shaped plants—which can increase a strawberry plant’s chance for survival.

Experiments with Arabidopsis, a small flowering plant related to cabbage and mustard, showed a similar regulation of the leaf margin features, suggesting that these shaping mechanisms may apply to many other plants as well.

Figuring out how plants control their leaf shapes offers scientists and agriculturalists new tools to help plants withstand heat and other climate conditions and conserve water more efficiently, bringing the world a step closer to meeting the challenges presented by climate change.

“Research like this has many implications for our efforts in conservation and agriculture,” Luo said. “We’re now better equipped to protect our natural resources and food supply from extreme conditions.”