Natural plant defense could fight cancer, protect crops

A natural defense that helps plants ward off insect predators, discovered at Washington State University, could lead to better crops and new treatments for cancer and Alzheimer’s disease.

Sachin Rustgi, adjunct assistant professor at the WSU Department of Crop and Soil Sciences, detailed the interaction of enzymes called proteases, and their inhibitors, along with the role they play in plant health and development, in the latest Proceedings of the National Academy of Sciences. The discovery could pave the way for advances in medicine and agriculture.

Sachin Rustgi
Sachin Rustgi

“By understanding this relationship, we can regulate it for our health and agricultural needs,” Rustgi said. “We can make enzymes available, or trap them when they’re not beneficial.”

A fine balance

As the building blocks of our bodies, proteins play important roles in plant and animal health. Special enzymes called proteases destroy proteins, and must be carefully controlled to avoid problems like disease and early aging.

Rustgi explored the relationship between a protease called RD21 and its inhibitors, Serpin1 and WSCP, in plants.

Researchers explored protease-inhibitor interaction in mouse-ear cress.
Researchers explored protease-inhibitor interaction in mouse-ear cress.

Predator defense

“When they first start growing, young plants are quite vulnerable,” said Rustgi, who first set out to study seedling defense, working with colleagues at Grenoble Alpes University and Jean Monnet University in France.

They found that when a seedling emerges from soil, inhibitors shut down and protease levels rise. When an insect tries to eat the plant, the protease attacks its digestive enzymes, causing the insect to seek a different meal.

Proteases inhibitors also influence plant resistance to disease and drought.

“Diseases that kill plants can be avoided by over-expressing these inhibitors,” said Rustgi. Proteases can also cause crops such as wheat, barley and corn to mature faster and avoid drought.

Safer drugs for human diseases

Better understanding of protease activity could also affect human health, Rustgi said. The discovery brings insights into cancer progression, and could lead to new therapies for cancer and other diseases.

“These proteins are similar in structure in animals and plants,” he said. “Most medicines for cancer and aging diseases are protease inhibitors. Understanding of how these proteins interact could lead to artificial inhibitors, and ultimately, safer medicines.”

Rustgi, currently at Clemson University, researched this natural defense system while working at WSU with co-author Diter von Wettstein, R.A. Nilan Distinguished Professor.

Their project was supported in part by the National Institute of Food and Agriculture and the Life Sciences Discovery Fund, established by Washington’s Governor and Legislature to foster growth of life sciences.

Source Contact

Sachin Rustgi, Adjunct Assistant Professor, WSU Department of Crop & Soil Sciences; Assistant Professor in Molecular Breeding, Clemson University; 843-519-0475, srustgi@clemson.edu