- Author: Kathy Keatley Garvey
Today, during the 62nd annual international conference of the Society of Nematologists, being held July 9-14 in Columbus, Ohio, The Proceedings of the National Academy of Sciences (PNAS) published a UC Davis research team's important--and exciting--research paper on root-knot nematodes.
It's online at “Root-Knot Nematodes Produce Functional Mimics of Tyrosine-Sulfated Plant Peptides."
Basically, the researchers discovered that “both a harmful plant bacterium and a parasitic worm can mimic a plant peptide hormone to enhance their ability to infect plants.”
It's a joint project of nematologist Shahid Siddique, an associate professor in the Davis Department of Entomology and Nematology, and Siddique and UC Davis distinguished professor Pamela Ronald, a plant pathologist and geneticist in the Department of Plant Pathology and the Genome Center. They are the corresponding authors. Joint first-authors are Henok Zemene Yemer, formerly of the Siddique lab and now with Gingko Bioworks, Emeryville, and Dee Dee Lu of the Ronald lab.
It's like hijacking plant development to facilitate parasitism, according to Siddique. “This finding showcases an amazing case of convergent evolution across three different types of organisms, revealing how diverse life forms can develop similar strategies for survival.”
“Root-knot nematodes are a major threat to various crops, including fruit trees and vegetables,” Siddique said. “In California, tomatoes, almonds, and walnuts are among the major hosts susceptible to root-knot nematode infection.”
Siddique and UC Davis distinguished professor Pamela Ronald, a plant pathologist and geneticist in the Department of Plant Pathology and the Genome Center, are the joint corresponding authors. Joint first-authors are Henok Zemene Yemer, formerly of the Siddique lab and now with Gingko Bioworks, Emeryville, and Dee Dee Lu of the Ronald lab.
Plant-parasitic nematodes (PPNs) are among the most destructive plant pathogens, causing an annual economic loss of $8 billion to U.S. growers and more than $100 billion worldwide, the authors said.
The team also included emerita professor Valerie Williamson of the former Department of Nematology; Maria Florencia Ercoli, postdoctoral fellow in the Ronald lab; Alison Coomer Blundell, a doctoral candidate in the Siddique lab; and Paulo Vieira of the USDA's Mycology and Nematology Genetic Diversity and Biology Laboratory, Beltsville, Md.
“Plant peptides containing sulfated tyrosine (PSY)-family peptides are peptide hormones that promote root growth via cell expansion and proliferation,” the authors explained. “A PSY-like peptide produced by a bacterial pathogen has been shown to contribute to bacterial virulence. Here, we discovered that PSY-like peptides are encoded by a group of plant-parasitic nematodes known as root-knot nematodes. These nematode-encoded PSY mimics facilitate the establishment of parasitism in the host plant. Our findings are an example of a functional plant peptide mimic encoded by a phytopathogenic bacterium (prokaryote) and a plant-parasitic nematode (an animal).”
The project drew financial support from a collaborative grant awarded to Siddique and Ronald from the National Science Foundation's Division of Integrative Organismal Systems.
Siddique, a member of the UC Davis faculty since 2019, focuses his research on basic as well as applied aspects of interaction between parasitic nematodes and their host plants. “The long-term object of our research is not only to enhance our understanding of molecular aspects of plant–nematode interaction but also to use this knowledge to provide new resources for reducing the impact of nematodes on crop plants in California.”
Ronald, noted for her innovative work in crop genetics, especially rice, is recognized for her research in infectious disease biology and environmental stress tolerance. Thomson Reuters named her one of the world's most influential scientific minds and Scientfic American recognized her as among the world's 100 most influential people in biotechnology. In 2022 Ronald received the Wolf Prize in Agriculture.
The next steps? “Currently, we are working to understand the mechanism by which these peptides contribute to the nematode infection,” Siddique said. “This entails the characterization of receptors involved and gaining insights into transcriptional changes.”
- Author: Kathy Keatley Garvey
What do flies have in common with us?
For one thing, an innate immune system mechanism to detect and fight off invaders that threaten our health.
Four scientists, including two Nobel Laureates, will discuss host defense at a UC Davis symposium on Wednesday, Jan. 25 in the UC Davis Conference Center.
Nobel Laureates Jules Hoffmann of the University of Strasbourg, France and Bruce Beutler of the University of Texas Southwestern Medical Center in Dallas will be among the speakers. They and Rockefeller University researcher Ralph Steinmann (who died in September) shared the 2011 Nobel Prize in Physiology or Medicine for their groundbreaking discoveries concerning the activation of innate immunity.
The symposium, sponsored by the UC Davis Center for Comparative Medicine and the
Murray B. Gardner Research Seminar Fund, will take place from 1 to 5 p.m. Open to all interested persons, it's free but folks must register at http://conferences.ucdavis.edu/immunity to attend.
"In recent years, a remarkable evolutionary conservation of innate immune mechanisms has become apparent between flies, plants, mice and humans," according to the sponsors' flier. "Each of these species uses similar receptors to detect microbes. Therapeutic targeting of toll-like receptors for infectious and inflammatory disease and cancer, and crop engineering of these receptors for resistance to infection, is now a reality."
The Theme
A Symposium on the Evolution of Common Molecular Pathways Underlying Innate Immunity.
The Speakers
"The Drosophila Host Defense: A Model for the Study of Innate Immunity"
--Jules Hoffmann, University of Strasbourg, 2011 Nobel Laureate in Physiology or Medicine
"Creating Immune Deficiencies by Random Mutagenesis in Mammals"
--Bruce Beutler, University of Texas Southwestern Medical Center, Dallas, 2011 Nobel Laureaute in Physiology or Medicine
"The Rice XA21 Receptor Recognizes a Conserved Bacterial Signaling Molecule"
--Pamela Ronald, professor, Department of Plant Pathology, and faculty, UC Davis Genome Center
"Toll-Like Receptors and Inflammasomes: Key Drivers of Inflammatory Diseases"
--Luke O'Neill, professor, School of Biochemistry and Immunology, Trinity College, Dublin
The Contact Person:
Anita Moore at (530) 752-1245.