UC San Diego biologists have identified two key pathways that plants use to respond to elevated temperatures, providing critical insights that could help enhance crop resilience in the face of climate change. This groundbreaking study has significant implications for agriculture and water management.
In a vital breakthrough with far-reaching implications for agriculture and food production, researchers at the University of California San Diego have mapped the intricate mechanisms plants employ to cope with rising temperatures. This discovery could pave the way for developing more resilient crop varieties, crucial as global warming intensifies.
Stomatal pores, the microscopic openings on leaf surfaces, play an essential role in plant respiration by regulating water loss and carbon dioxide intake. Historical observations, dating back to the 19th century, have noted that plants widen these stomatal pores to cool down and survive heatwaves. However, the genetic and molecular specifics of this process have remained elusive — until now.
The research, spearheaded by doctoral student Nattiwong Pankasem and Julian Schroeder, a professor of biological sciences at UC San Diego, identifies two distinct genetic pathways that plants activate in response to increasing temperatures.
Their findings, published in the journal New Phytologist, reveal a detailed picture of these pathways.
“With increasing global temperatures, there’s obviously a threat to agriculture with the impact of heat waves,” Schroeder said in a news release. “This research describes the discovery that rising temperatures cause stomatal opening by one genetic pathway (mechanism), but if the heat steps up even further, then there’s another mechanism that kicks in to increase stomatal opening.”
For decades, scientists have struggled to pinpoint these mechanisms due to the complex nature of measuring stomatal responses and the difficulty of isolating temperature and humidity effects.
Pankasem’s innovative approach, which involves a new generation gas exchange analyzer and a method to maintain constant vapor pressure difference (VPD) in leaves, finally made it possible to isolate and study these genetic responses.
The findings have profound implications.
“This work shows the importance of curiosity-driven, fundamental research in helping to address societal challenges, build resiliency in key areas like agriculture and, potentially, advance the bioeconomy,” Richard Cyr, a program director in the U.S. National Science Foundation Directorate for Biological Sciences, said in the news release.
The study identified that in moderately elevated temperatures, carbon dioxide sensors play a crucial role. These sensors detect rapid warming, which triggers increased photosynthesis and reduces carbon dioxide levels, prompting stomatal opening. However, under extreme heat conditions, a secondary pathway bypasses these sensors. This response can lead to a decrease in photosynthesis efficiency, causing plants to use more water per unit of carbon dioxide absorbed.
“The impact of the second mechanism, in which plants open their stomata without gaining benefits from photosynthesis, would result in a reduction in water use efficiency of crop plants,” added Pankasem. “Based on our study, plants are likely to demand more water per unit of CO2 taken in. This may have direct implications on irrigation planning for crop production and large-scale effects of increased transpiration of plants in ecosystems on the hydrological cycle in response to global warming.”
The implications of this discovery are significant. It provides a roadmap for future research aimed at developing crop varieties that can withstand the dual challenges of heat and water scarcity. Pankasem and Schroeder’s ongoing work to further elucidate the molecular and genetic underpinnings of these heat response mechanisms underscores the critical role of fundamental research in solving real-world problems.
The research team includes Po-Kai Hsu, Bryn Lopez and Peter Franks. Their continued investigations promise to advance our understanding of plant biology and bolster agricultural resilience in an uncertain climate future.