Source: Iowa State University of Science and Technology

Iowa State University researchers are leading two studies investigating how potato plants respond to their environment with the potential of increasing yields of the world's fourth most important food crop.

Grants from the National Science Foundation (NSF) and the USDA worth $3.15 million are funding the studies of how the potato plant sends signals within the plant. David Hannapel, professor of horticulture, leads the NSF project and is co-leader on the USDA project with Aragula Rao, professor and chair of the biochemistry, biophysics and molecular biology department.

Plants receive environmental signals that activate molecular pathways to control defense, development and metabolism, Hannapel said. The length of daylight is a key environmental signal that regulates flowering, dormancy and tuberization of the potato.

"Tuberization in potatoes is particularly intriguing as it involves the delivery of a light signal from the light-receiving organ, the leaf, to an underground organ, the stolon," he said. "The overall scientific objective of these projects is to uncover the network of signals that are responsible for the light-activated process of tuber formation."

Hannapel said recent discoveries have demonstrated the role of a mobile RNA in a signaling system that activates tuber formation. RNA, ribonucleic acid, is a molecule present in all living things that plays a part in protein production and transmitting genetic information.

"Full-length mobile RNAs that move long distances in plants and act as signals for development and defense are a novel idea in plant biology," Hannapel said. "The value of our work is that it provides a model for understanding how such signal RNAs are moving and what determines their final destination."

Rao will work to identify and characterize the proteins that recognize mobile RNAs," he said. "We will use both targeted and random approaches to do this."

The work also has the possibility of boosting potato production.

"We are fortunate that the RNAs we study in potato activate tuber formation and in this way, regulate tuber yields," he said. "So this system can potentially be used to enhance crop productivity. When considering calories generated for human consumption per acre, potato is the most productive food crop on the planet and is a critical staple in many developing countries."

Working with Hannapel and Rao on the NSF-funded project are Jeff Coller of Case Western Reserve University and William Lucas of the University of California-Davis.