September 4, 2020

Environmental stress such as drought, extreme heat or salinity can have a devastating impact on plant growth and productivity and even entire ecosystems. 

A new study co-led by Rajeev Azad, associate professor of bioinformatics in UNT’s College of Science, looks at how plants respond to different types of stress at the same time — something that previously has not been studied in depth. A better understanding could help develop more resilient plants, which is much needed as climate change continues to accelerate.

“Understanding how plants acclimate to different stress combinations will help researchers develop strategies to make crops more tolerant to harsh environmental conditions,” Azad says. “This is a pressing need because of the deteriorating climatic conditions that are expected to get worse in the near future and which could inflict a heavy loss to agriculture resulting in a huge socioeconomic impact worldwide.”

Anyone who has forgotten to water the plants on their patio in 100-degree heat knows that when leaves experience stress, the plant responds. When plants are subjected to specific factors such as too much heat or sunlight — known as abiotic stresses, signaling mechanisms are triggered that enable plants to acclimate to the harsh conditions. But what if one leaf is exposed to too much heat and another to too much sunlight? In nature, plants are routinely subjected to a combination of multiple stresses simultaneously.

“Much is known about how plants respond to individual abiotic stresses,” Azad says. “However, the response of plants to stress combination is not yet well-understood.”

Azad and graduate research assistant Soham Sengupta have been investigating how plants integrate these different signals caused by different types of stress. It turns out that leaves can communicate with each other. How well they respond depends on which parts are being affected, for instance whether multiple leaves are being stressed at the same time or whether individual leaves are being subjected to different stresses.

The research, which received funding from the National Science Foundation, is an ongoing collaboration between Azad’s lab and plant researcher Ron Mittler’s lab at the University of Missouri. Their findings were recently published in the Proceedings of the National Academy of Sciences in a paper titled “Systemic signaling during abiotic stress combination in plants.”

“This study focused on the combination of only two stresses — high light and heat, but we know that in reality there could be many more stresses acting simultaneously on organisms,” Azad says. “This work may spur studies on multifactorial stress combination, which can reveal the roles of biomolecules and their networks in responding to different multifactorial stress combinations, and thus pave the way toward making plants more tolerant.”