Khalimonchuk, Wilson named AAAS fellows

Two University of Nebraska–Lincoln faculty have been selected as fellows of the American Association for the Advancement of Science, the world’s largest multidisciplinary scientific society. Fellows are selected by their peers for scientifically or socially distinguished achievements that advance science or its application.

Nebraska’s new AAAS fellows are:

• Oleh Khalimonchuk, Susan J. Rosowski Professor of biochemistry, for distinguished contributions to the field of mitochondrial biology, particularly for advancing the understanding of multiple mitochondrial functions in health, cellular stress and degenerative diseases.

• Richard Wilson, professor of plant pathology, for distinguished contributions to the understanding of the genetic and biochemical underpinnings that govern plant-microbe interactions, particularly the devastating blast disease caused by the fungal pathogen Magnaporthe oryzae.

Khalimonchuk and Wilson are part of the 505-member cohort of 2022 AAAS fellows. They will be recognized in the February edition of the journal Science and honored this summer in Washington, D.C.

More about Nebraska’s new AAAS fellows:

Oleh Khalimonchuk

Khalimonchuk is at the forefront of expanding understanding of the role of mitochondria, the cell components traditionally recognized as the “powerhouses” that convert oxygen and nutrients to heat and energy. Khalimonchuk’s work spotlights mitochondria’s much broader role — particularly as it relates to human health.

“On top of mitochondrial genetic disorders, which affect one in every 5,000 live births, you have this gradual decline of mitochondrial functionality that is happening in virtually every complex disorder, be it heart failure, diabetes, cancer or whatnot,” he said. “This is where our work has been recognized particularly.”

Khalimonchuk, who has received more than $6 million in external funding, has two primary areas of focus. He studies the mitochondria’s quality-control system, a multi-layered network of proteins working in concert for maintenance and repair. System disruptions can lead to degenerative diseases like Lou Gehrig’s, Parkinson’s and Alzheimer’s, and may contribute to certain cancers.

He also studies the biosynthesis and trafficking of mitochondrial heme, a substance present in 90% of the blood’s hemoglobin. Heme synthesis is well understood, but how it is transported around the cell remains unclear. Khalimonchuk discovered that heme mobilization occurs in nearly simultaneous parallel pathways rather than sequentially in different parts of the cell, which challenges a long-held theory.

Khalimonchuk was one of the first researchers to detail the role of the protease Oma1 in mitochondrial physiology and identify its tumor-suppressive role in breast cancer. When he started studying Oma1 11 years ago, there were about nine papers published on the topic. Now, thanks to his work to jump-start the field, there are more than 150.

With University of Miami collaborators, Khalimonchuk also upended a decades-old paradigm related to the assembly of cytochrome c oxidase, a vital enzyme residing in mitochondria. His findings shed light on the enzyme’s role in human disease.

Khalimonchuk, director of the university’s Redox Biology Center since 2020, hopes his work will eventually contribute to treatments.

“It’s always great to make basic discoveries, but one of my long-term goals is to put these discoveries to work and actually develop solutions to mitigate mitochondrial diseases.”

Richard Wilson

Wilson focuses on plant-microbe interactions, specifically the genetic and biochemical processes that enable the fungal pathogen Magnaporthe oryzae to survive and thrive in host plants.

M. oryzae causes rice blast disease, which spoils up to 30% of the world’s potential rice yields each year. It can also affect other grass species, including wheat, which amplifies its threat to food security.

Wilson’s approach to studying the plant-microbe relationship differentiates his work from other research in the field.

“I’m convinced it’s our focus on fungus metabolism and growth that has enabled us to stand out,” Wilson said. “A lot of people in the field are thinking about it from the plant side, asking, ‘How can we stop disease?’ We are exploring the pathogen side of the interaction, asking instead, ‘How does the fungus cause disease?’”

This strategy has led to novel findings. In 2020, Wilson’s team identified an organic compound, spermine, and the gene responsible for its synthesis, SPS1. Both help the fungi produce mucilage, a substance that is a key player in fungal infiltration of a rice plant. The finding could open the door to new approaches for combating the parasitic fungus.

More recently, his team has uncovered a previously unknown route by which M. oryzae secretes substances into a plant to suppress its defenses. The finding connects the rules for protein translation and secretion in a new way and may help pinpoint methods for stymying the fungus’ invasion. Wilson aims to publish these results later this year.

Though M. oryzae is his niche, Wilson’s work may help protect agricultural yields more broadly, as many plant pathogens evade host defenses using similar mechanisms. Looking forward, he hopes to expand his work beyond plants, possibly translating his work to human health, and build collaborations that include a broader range of expertise.

“I’m very pleased, excited and overwhelmed that my peers recognize my scientific achievements up to this point, and they see that the research is likely to have momentum into the future.”