Lessons in Resilience from a Primitive Plant

Biological sciences Ph.D. candidate Priyanka Bharadwaj studies an ancient plant that may hold the key to understanding how plants can adapt to and survive extreme conditions. 

As the world grapples with natural disasters like wildfire and flood, the need for resilient ecosystems and agriculture has never been more critical. Unpredictable weather patterns and increasing frequency of extreme events threaten the world’s food security and wildlife. Today, scientists around the world are working to understand how to protect our water, energy, wildlife and food supply from these ecological disruptions.  

University of Maryland biological sciences Ph.D. student Priyanka Bharadwaj is particularly interested in how environmental stresses and extremes could impact growing plants, and she is turning to one of Earth’s most primitive plants for answers. She believes that Marchantia (also known as the common liverwort) can reveal just how plants adapt to—and even thrive in—challenging conditions.  

“Marchantia is often the first vegetation to grow after a wildfire and was also one of the earliest plants to colonize land, with ancestors dating back over 400 million years,” Bharadwaj explained. “This ancient lineage makes it a valuable blueprint and model for understanding how plants have evolved to cope with environmental stresses, a topic that’s become increasingly relevant as we see more extreme conditions from droughts, fires and floods.”

Working with Cell Biology and Molecular Genetics Professor Caren Chang, Bharadwaj hopes to learn how Marchantia responds to environmental stresses and plant hormones such as ethylene (a colorless gas involved in plant development) and its chemical predecessor, 1-aminocyclopropane-1-carboxylic acid (ACC).  

In 2022, Bharadwaj led a study published in Frontiers in Plant Science that found that ethylene plays a key role in plant survival. Working with Marchantia plants that could sense ethylene and mutant plants that could not, she tested each plant against environmental stresses like heat, salinity, nutrient deficiency and far-red light (a range of light only dimly visible to humans). Bharadwaj and her team discovered that Marchantia plants that couldn’t detect ethylene struggled to survive the tougher conditions.

“We also found that plants make more ethylene when they’re stressed, which indicates that the hormone really helps protect them from challenging environments,” Bharadwaj said. “Our findings suggest that ethylene has probably been helping plants deal with stress for a very long time.”

Chang noted Bharadwaj’s contributions played a key role in the ethylene study, which listed her as first author and was published in her first year at Chang’s lab. 

“Priyanka joined my lab in summer 2021 and immediately took the lead on work involving Marchantia and ethylene,” Chang recalled. “Within her first 12 months in my lab, we wrote and submitted a manuscript on this research, which was accepted just two months later. It was an unusually quick breakthrough and evidence of her research and leadership abilities.”

Growing new roots

For Bharadwaj, her first few years at UMD were challenging and exciting. As a new international student from India, she was stepping into a world vastly different from what she knew. 

“I was living alone for the first time, thousands of miles away from my parents and my twin sister. I had to deal with remote learning and social distancing while I was also navigating cultural differences,” she recalled. “But being in Caren’s lab and working helped me quickly settle in and I was able to collaborate with other researchers, so there was a semblance of normality.”

Despite the initial hurdles, Bharadwaj quickly flourished and found a new home at UMD and beyond. She works with collaborators from KU Leuven in Belgium and the University of North Carolina, Chapel Hill to expand her plant resilience research.

“I get to see so many different ways of applying plant science while at UMD,” Bharadwaj said. “Whether I end up in academia or industry after completing my Ph.D. program here, I know I want to be at the forefront of discovery, pushing beyond what we now know about plants.” 

Bharadwaj also continues to build on her prior ethylene research by digging deeper into how ethylene’s chemical predecessor ACC affects growing plants. Research from the Chang lab previously demonstrated that ACC and ethylene elicit distinctly different responses in Marchantia, providing compelling evidence that ACC functions as an independent signaling molecule. To confirm this theory, Bharadwaj plans to work with ACC-insensitive Marchantia plants to see how it acts as a signal in these plants.

“I hope to use a combination of genetic sequencing and experimental approaches to explore whether ACC plays a specific role in their growth of development,” Bharadwaj said. “If it does, it could mean implications for breeding more resilient crops that are better equipped to adapt to tough conditions.”

Looking ahead, Bharadwaj believes that her work is more than just observing an ancient plant. She hopes that the work will inform strategies to improve crop resilience and give agriculturists a leg up on breeding stronger plants that can withstand future environmental challenges. 

“There’s a lot to learn from a plant like Marchantia because it’s an evolutionary success story,” she said. “Understanding how it reacts to certain stresses like temperature, salinity and nutrient deficiency can help us figure out how to increase the resiliency of our agricultural systems and protect our food supply in the coming years.”