Coping: Plant adaptability to stress discovered

Most people who get too hot and thirsty this summer can quickly grab a cool drink. Not so for plants. Their roots keep them lingering in stressful situations – sometimes to death. Now a Texas A&M University researcher has identified a system in a mutant arabidopsis, a type of weed, that signals to its cells to go on hold until stressful situations pass.

The involvement of “ER stress signal pathway” in plant stress adaptation was discovered by Dr. Hisashi Koiwa, assistant professor of horticultural sciences, and colleagues. Koiwa is presenting the finding at the annual meeting of American Society of Plant Biologists this week (July 26-31) in Hawaii. The findings also will appear in an upcoming issue of the journal “The Plant Cell.”

“A plant will attempt to regulate itself when stressed by adjusting its cells to the environment before starting to grow again,” Koiwa said. “It´s as if a plant is saying to itself, – wait, we´re in a drought, let´s adjust before we grow anymore. “A plant must have a better stress handling technique,” he added.

The scientist explained that when a plant is stressed, it has to rest until it adjusts because if plant cells continue to divide under stress, they might “burst.” Something signals a plant to pause, he said, but scientists have never fully studied the systems of plants. His research, funded in part with a National Science Foundation grant through collaboration with Purdue University researchers, describes how the process works in the mutant arabidopsis.

“It´s a natural way for the plant to sense stress and signal to adjust,” Koiwa said. “The concept is not new, but it had not been fully established prior to this research.” He said researchers now can look closer at the process to see what happens in other plants. In the long term, he said, plant breeders might use this knowledge to breed plants that are more able to adjust to various environment stresses such as extreme temperatures or the lack or abundance of water.

“If a species of plants can´t take a drought, perhaps a plant breeder could enhance the ER stress signal pathway to enable that species to be more adaptable so that it can survive and grow well,” Koiwa said. “Otherwise, in many cases, a plant responds to such stress too late to recover.”

But more information is needed. Researchers now know there is a system, but don´t understand why it works as it does. He said it is similar to understanding that the muscle system in humans allow for movement, but knowing why is necessary to find medical answers for failed muscles.

Researchers now may take the study a step further, Koiwa said, to find out the “mechanism a plant uses to hold on for the stress and the mechanism a plant uses to indicate it is ready to start cell division again.”