Perfect timing.

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.”

The root-knot nematode, which threatens global food security, is a small worm-like organism that is a highly evolved obligate parasite, or an organism that cannot survive without its host. It is known to infest some 2000 crops worldwide. “These parasites have a remarkable ability to establish elaborate feeding sites in roots, which are their only source of nutrients throughout their life cycle,” the authors wrote.

“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 research involved gene expression analysis and parasitism of tomato and rice plants.

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.”

Ever heard of Carey's Equality?

Do you know who discovered it?

That would be UC Davis distinguished professor James R. Carey of the Department of Entomology and Nematology, who will present a departmental seminar at 4:10 p.m.  Wednesday, May 25, on "The Conceptual Sweep of a Mathematical Discovery in Insect Biodemography: From Medfly Populations to the U.S. Congress."

You can attend the seminar in person at 122 Briggs Hall, UC Davis campus, or access it via Zoom. The Zoom link is https://ucdavis.zoom.us/j/99515291076.

"Twenty years ago while attempting to develop a new concept for studying insect aging in the wild, I discovered a previously unknown mathematical identity now referred to in the formal demography literature as the eponym Carey's Equality—the age distribution of a stationary population equals the distribution of lifetimes yet to come," Professor Carey says in his abstract. "In this seminar I will present my attempts at both operationalizing the concept for study of populations of insects and other non-human species, and generalizing it for applications to groups with fixed numbers of members and where renewal involves birth and death processes."

"These general applications include data from a British cemetery, the National Basketball Association, the Baltimore Longitudinal Health Study, the U.S. Congress (both chambers) and the world population," said Carey, a member of the UC Davis Department of Entomology and Nematology faculty since  1980.  "After discussing implications and extensions of the identity, I will wrap up with descriptions of five simple but important demographic relations that all entomologists should know."

Highly honored for his research, teaching and public service, Carey served as the principal investigator of a 10-year, $10 million federal grant on “Aging in the Wild,” encompassing 14 scientists at 11 universities. 

Biodemography Textbook. In 2020, he and Deborah Roach, professor and chair of the University of Virginia's Department of Biology, co-authored a 480-page textbook, Biodemography: An Introduction to Concepts and Methods, published by Princeton University Press  and hailed as the “definitive textbook for the emerging field of biodemography, integrating biology, mathematics and demography.” Carey recently created a free-access, video guidebook with a playlist of 175 separate presentations, subtitled in 300 different languages. He storyboarded the script, turned graphs, schematics, tables and equations into animated slides,  and then with teleprompter assistance, narrated and video-recorded the 175 presentations, which span 12 hours of viewing. It appears on UC Berkeley Population Sciences website at https://bit.ly/3FTge7u.

An internationally recognized teacher, Carey won a 2018 global award in the Robert Foster Cherry Award for Great Teaching Program, an academic competition sponsored every two years by Baylor University, Waco, Texas. He received the 2015 Distinguished Achievement in Teaching Award from the Entomological Society of America (ESA) and the 2014 Distinguished Teaching Award from the Pacific Branch of ESA. The UC Davis Academic Senate honored him as the recipient of its 2014 Distinguished Teaching Award, given to internationally recognized professors who excel at teaching.

Carey is a fellow of four organizations: American Association for the Advancement of Science, Entomological Society of America, California Academy of Science and the Gerontological Society of America. He holds a doctorate in entomology (1980) from UC Berkeley, and two degrees from Iowa State University: a bachelor of science degree in animal biology (1973) and a master's degree in entomology (1975).

Nematologist Shahid Siddique, assistant professor, UC Davis Department of Entomology and Nematology, coordinates the spring seminars. He may be reached at ssiddique@ucdavis.edu for any technical issues regarding Zoom. (See complete list of spring seminars.)

"The use of synthetic chemical pesticides is central to current agricultural practices worldwide. But what is the cost to wildlife via non-target exposures? This talk will summarize when there's risk to bees, when there isn't, and what types of research are most likely to influence farmers, regulatory agencies, and policy makers."

So says Scott McArt, an assistant professor in the Cornell University's Department of Entomology, who will speak on "Pesticide Risk to Pollinators: What We Know and What We Need to Know Better" at the Wednesday, May 4 virtual seminar hosted by the UC Davis Department of Entomology and Nematology. 

The seminar begins at 4:10 p.m. The Zoom link: 
https://ucdavis.zoom.us/j/99515291076

McArt, who joined the Cornell faculty in 2017, focuses his research on pollinator health and ecology. His areas of expertise include disease ecology, ecotoxicology, community ecology, chemical ecology, and plant-pollinator interactions. He  maintains his lab research site at https://blogs.cornell.edu/mcartlab/. 

"Research in our lab focuses on the impact of pesticides, pathogens, and habitat on honey bees and wild bees," he writes on his website. "We are particularly interested in scientific research that can inform management decisions by beekeepers, growers and the public. Current research projects include: 1) Understanding pesticide exposure and risk to bees in multiple land management contexts, 2) Combining empirical data with network modeling to understand pathogen transmission in complex plant-pollinator networks, and 3) Understanding how habitat enhancements (e.g., flowers at solar power sites) impact pollinator populations and the services they provide to agriculture."

McArt's duties at Cornell also include director of the Cornell Chemical Ecology Core Facility, and associate curator of the Cornell University Insect Collection.

He writes a monthly column, Notes from the Lab, in American Bee Journal; each month he summarizes scientific publications for a non-scientific audience. "The goal is to make the emerging pollinator health science more approachable and relevant to beekeepers," he says.

He is also a member of the New York State (NYS) Beekeeper Tech Team, which works directly with NYS beekeepers to improve honey bee health, reduce colony losses, and increase profitability of the state's beekeeping industry: https://pollinator.cals.cornell.edu/nys-beekeeper-tech-team/

In addition, McArt coordinates such beekeeping workshops as "Introduction to Honey Bee Queen Rearing" and "Honey Bee Biology and Disease Management for Veterinarians" and engages with growers regarding pesticide risk to bees and creating pollinator-friendly habitat. His extension materials are onsite.  

When asked "What gets you out of bed in the morning?" during a new faculty interview, he responded "Most of the factors contributing to declines in bee health (pesticide exposure, lack of floral resources, disease, inadequate management practices) are preventable. With targeted research efforts and educated stakeholders, regulatory agencies and public, we can make a difference."

McArt holds a bachelor of arts degree in environmental and evolutionary biology (2001) from Dartmouth College, Hanover, N.H., and a master's degree in biological sciences (2006) from the University of Alaska, Anchorage. He received his doctorate in entomology in 2012 from Cornell University. He served as a USDA-NIFA (National Institute of Food and Agriculture) postdoctoral fellow at the University of Massachusetts, Amhurst, in 2014, and then as a research scientist at Cornell from 2014 to 2017, before joining the Cornell faculty. 

Nematologist Shahid Siddique, assistant professor, UC Davis Department of Entomology and Nematology, is coordinating the spring seminars. For Zoom technical issues, contact him at ssiddique@ucdavis.edu.

(See complete list of spring seminars.)

Don't miss this seminar by Tobin Hammer Wednesday, April 13 on "Mystery of the Missing Microbes: Why Do Bees Keep Losing Their Symbionts?"

Hammer, assistant professor of ecology and evolutionary biology, UC Irvine, will give the in-person and virtual seminar, hosted by the UC Davis Department of Entomology and Nematology, at 4:10 p.m. in 122 Briggs Hall. The Zoom link:  https://ucdavis.zoom.us/j/99515291076. 

Community ecologist Rachel Vannette, associate professor, UC Davis Department of Entomology and Nematology, is hosting the seminar.

"How do insects and microbes form symbioses, and why do these partnerships often break down?" Hammer asks in his abstract. "We are addressing these questions with the gut microbiomes of social corbiculate bees. Despite an ancient association with their bee hosts, these symbionts are surprising dynamic over developmental, ecological and macroevolutionary time scales. I will discuss our recent discoveries of symbiont loss in bees, and efforts to understand why and how these losses occur."

Hammer received his bachelor's degree in general biology from UC San Diego in 2009 and his doctorate in evolutionary biology in 2018 from the University of Colorado, Boulder.  He served as a postdoctoral researcher at the University of Texas, Austin, from 2018 to 2021.

Hammer's research interests include microbiomes, symbiosis, microbial ecology and evolution, bees, biodiversity, insect-plant interactions and tropical biology.

"We are a new research group at UC Irvine studying the ecology and evolution of symbioses between hosts (especially bees) and microbes," he writes on his lab website. 

Nematologist Shahid Siddique, assistant professor, UC Davis Department of Entomology and Nematology, is coordinating the spring seminars. For Zoom technical issues, contact him at ssiddique@ucdavis.edu.

(See complete list of spring seminars.)