Iowa State University researchers including, from left, distinguished professor of biochemistry, biophysics and molecular biology Reuben Peters, sophomore Tristan Weers and doctoral student Yiling Feng, recently identified two genes connected to how rice plants ward off fungal disease.
Newswise — AMES, Iowa — Researchers at Iowa State University have identified two genes that can help rice defend itself against diseases, including the devastating fungal blast pathogen that regularly causes significant losses of rice production worldwide.
More than half the world’s population depends on rice as an essential daily food staple. The crop, which grows in moist conditions, is especially vulnerable to fungal diseases. Many of rice’s defenses stem from natural plant antibiotic compounds called diterpenoids. Recently, a large class of these compounds were newly identified and found to function as antibiotics against fungal pathogens.
These compounds appeared to be made from a diterpene called miltiradiene. However, that chemical wasn’t produced by any known gene; rice seemed to be making these antibiotics out of nowhere – not the way nature usually works.
Biochemistry detective project
Reuben Peters, Distinguished Professor in Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology (BBMB) at Iowa State, and members of his laboratory, set out on a biochemistry detective project to find the missing link to miltiradiene.
With leadership from two students in his lab group, Yiling Feng, a PhD student in the Interdepartmental Plant Biology Program, and Tristan Weers, a sophomore in biochemistry, they have found at least some of those critical missing links. They identified two genes (OsKSL14 and OSKSL10) linked to miltiradiene production in rice, and, hence, disease resilience.
Feng first found OsKSL14. The gene had not yet been characterized, but her research indicated it might be responsible for making miltiradiene. OsKSL10 is closely related to OsKSL14, which suggested that it also might be involved. Feng worked with Weers to clone the genes, and Weers was then able to confirm that both genes encode enzymes that produce miltiradiene and trigger production of its natural antibiotic compounds.
“This makes the genes extremely important,” Feng said. “I come from China where rice is a basic part of our diet every day, so this could be a real benefit to countries like mine.”
The research group’s discovery has been accepted for publication in the scientific journal aBIOTECH, in a paper Peters co-authored with Feng and Weers.
“This work represents an important contribution to the basic understanding of rice, providing valuable insights into the evolution of rice diterpenoid natural products and their functions,” Peters said.
“This research offers new tools rice breeders can use to enhance resilience and productivity in their cultivars,” he continued. “The traits these disease-resistant genes can provide are likely to become more important as climate change brings new pathogens to areas where the genes were not really needed earlier in the plant’s evolution.”
From gene discovery to international research opportunity
Peters gives a lot of credit for the discovery to his young laboratory advisees. “Yiling’s insights and work have been critical to the success of this project. Tristan has also played an important role for helping firm up the implications of our findings.”
One of the “coolest” aspects of this research for Weers has been the chance to learn about rice, a major crop globally that he had not had any experience with. He grew up on a farm in eastern Iowa and came to college interested in research, inspired by AP science classes and the chance to help design a lab to support them at Anamosa High School. As he began to look for opportunities at Iowa State, Claire Kruesel, a student services specialist in BBMB, helped him find his way to the Peters Lab. He started work there during his second semester on campus.
“I didn’t come to college with a lot of research experience,” Weers said. “I did know a few things, like what a pipette was for. Dr. Peters and the graduate students in the lab have been so gracious to support me, and I try to learn something new every time I come to the lab.”
Last summer, Weers was selected for a Beitz Fellowship to participate in the second cohort of BBMB’s Biochemistry Summer Research Program for undergraduates. He has also been involved in creating awards for the Stupka Research Symposium. Inspired during a tour of the campus’ Student Innovation Center, he worked with a faculty member to use lasers and a 3D printer to fabricate new trophies for this coming year’s poster session winners.
Mentoring emerging researchers is nothing new for Peters, who has had undergraduates working alongside graduate students in his lab since he joined the Iowa State faculty more than 20 years ago. Thanks to Peters’ connections from a sabbatical at the world-renowned Max Planck Institute for Chemical Ecology in Germany, Weers will have the chance to hone his research skills there over the summer.
“I feel really excited and lucky to have this opportunity,” Weers said.
In the meantime, the team in the Peters Lab has work to do. They have found at least five more uncharacterized rice genes and plan more sleuthing to see if their functions can be revealed.
Their work has been supported by grants from both the USDA Agriculture Food and Research Initiative and National Institutes of Health.
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