- Author: Kathy Keatley Garvey
The open-access journal Nature Communications, published the peer-reviewed research Oct. 19.
“Plant-parasitic nematodes are a threat to crop production,” said Siddique, an assistant professor in the UC Davis Department of Entomology and Nematology. “We used a combination of genomic, genetic, and biochemical approaches to show that the plant pathogen cyst nematode possesses an incomplete vitamin B5 synthesis pathway, of potential prokaryotic origin, which is complemented by its plant host. This approach has identified new targets for future development of nematode-resistant crops.”
The 33-member research team included scientists from universities in Germany, France, The Netherlands, Poland, and the United Kingdom, as well as scientists from three universities in the United States: Iowa State University, Ames; and the University of Tennessee, Knoxville; and UC Davis.
The article is titled “The Genome and Lifestage-Specific Transcriptomes of a Plant-Parasitic Nematode and its Host Reveal Susceptibility Genes Involved in Trans-Kingdom Synthesis of Vitamin B5.”
“The scarcity of classical resistance genes highlights a pressing need to find new ways to develop nematode-resistant germplasm,” the scientists wrote in their abstract. “Here, we sequence and assemble a high-quality phased genome of the model cyst nematode Heterodera schachtii to provide a platform for the first system-wide dual analysis of host and parasite gene expression over time, covering all major parasitism stages. Analysis of the hologenome of the plant nematode infection site identified metabolic pathways that were incomplete in the parasite but complemented by the host. Using a combination of bioinformatic, genetic, and biochemical approaches, we show that a highly atypical completion of vitamin B5 biosynthesis by the parasitic animal, putatively enabled by a horizontal gene transfer from a bacterium, is required for full pathogenicity. Knockout of either plant encoded or now nematode-encoded steps in the pathway significantly reduces parasitic success. Our experiments establish a reference for cyst nematodes, further our understanding of the evolution of plant parasitism by nematodes, and show that congruent differential expression of metabolic pathways in the infection hologenome represents a new way to find nematode susceptibility genes. The approach identifies genome-editing-amenable targets for future development of nematode-resistant crops.”
Corresponding authors are Florian Grundler of the Rheinische Friedrich-Wilhelms-University of Bonn, Germany, and Sebastian Eves-van den Akker of the Crop Science Centre, Department of Plant Sciences, University of Cambridge, UK.
Research in the Siddique lab focuses on basic as well as applied aspects of interaction between parasitic nematodes and their host plants. “Plant-parasitic nematodes are destructive pests causing losses of billions of dollars annually,” Siddique said. “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.”
- Author: Kathy Keatley Garvey
Mostafa Zamanian, an assistant professor in the Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, will speak on "Combing Target and Whole-Organism Paradigms for Anthelmintic Discovery" at the May 11th virtual seminar hosted by the UC Davis Department of Entomology and Nematology.
His seminar begins at 4:10 p.m., Pacific Daylight time. The Zoom link is https://ucdavis.zoom.us/j/99515291076.
"Soil and vector-transmitted parasitic nematodes (roundworms) infect over one billion people and are a major cause of global morbidity," Zamanian says in his abstract. "Parasite control in both human and animal medicine is suboptimal and threatened by the growing prospects of anthelmintic resistance. Motivated by the need for new treatments and curiosity about basic parasite biology, I will present recent work addressing questions about how mosquito-transmitted parasitic nematodes navigate through host tissues and manipulate their host environments to survive. We will discuss how advanced transcriptomic approaches can move us towards a better understanding of the molecular basis for these essential parasite behaviors, and how we can effectively combine 'target-based' and 'whole-organism' screening pipelines to help identify novel antiparasitics."
Zamanian holds a bachelor's degree in biochemistry and a doctorate in neuroscience from Iowa State University. He served as a postdoctoral fellow at McGill University and Northwestern University before joining the faculty of the University of Wisconsin.
On his website, Zamanian relates that "Neglected Diseases (NTDs) caused by parasitic worms (helminths) impose a debilitating health and economic burden throughout much of the world. These global diseases of poverty infect over 1.5 billion humans and exert their damage through a wide range of species-specific clinical manifestations. Parasitic diseases are also a major challenge to animal and plant health. The central ambition of our laboratory is to combine molecular, genetics, and computational approaches to make discoveries that improve our understanding of parasite biology and host-parasite interactions, as well as our ability to treat parasitic infections. This includes identifying new targets for drug discovery, elucidating mechanisms of drug resistance, and developing new tools for parasite manipulation and phenotypic screening. We directly study human and animal parasites, including mosquito-borne filarial nematodes, soil-transmitted nematodes, and snail-transmitted blood flukes."
Nematologist Shahid Sidduqe coordinates the Department of Entomology and Nematology seminars. For any technical issues regarding the Zoom link, contact him at ssiddique@ucdavis.edu.
- Author: Kathy Keatley Garvey
Her virtual seminar begins at 4:10 p.m., Pacific Time, on Wednesday, March 9, announced seminar coordinator and nematologist Shahid Siddique, assstant professor, UC Davis Department of Entomology and Nematology.
"Phytonematodes secrete a suite of effectors to modulate developmental programs of their hosts to cause disease," Mitchum says in her abstract. 'In this talk, I will highlight what we are learning about these effectors and the tricks they use to accomplish their goals."
Along with colleague Lisa Beamer of the University of Missouri, Mitchum is co-directing a four-year $1.2 million grant from the joint National Science Foundation and the U.S. Department of Agriculture National Institute of Food and Agriculture Plant-Biotic Interactions Program "to help combat a devastating soybean pathogen," according to a January 2022 news article in the Johnson City Press, Tenn. "The soybean cyst nematode, a microscopic roundworm, is responsible for annual crop losses of $1 billion in the U.S. alone," the news story relates.
Mitchum's research focuses "on molecular plant-nematode interactions with an emphasis on the sedentary endoparasitic cyst and root-knot nematodes," Mitchum says on her website. "Pathosystems include cyst (Heterodera glycines) nematode on soybean, cyst (Vittitadera zeaphila) nematode on corn, and root-knot (Meloidogyne spp.) nematodes on soybean, cotton, and peanut. We utilize the model plant Arabidopsis to accelerate our studies to dissect the molecular basis of parasitism by cyst (Heterodera schachtii) and root-knot nematodes. Our work addresses plant responses during compatible and incompatible plant-nematode interactions, the identification and functional analysis of nematode stylet-secreted effector proteins, and developmental reprogramming of host root cells via peptide mimicry and phytohormone manipulation. I work closely with plant breeders to develop high yielding, nematode resistant varieties. Current efforts are also focused on translating basic discoveries to develop novel approaches for nematode resistance in crop plant."
Mitchum received her bachelor's degree in biology in 1993 from the University of Puget Sound, Tacoma, Wash., and her master's degree in plant pathology from the University of Nebraska, Lincoln, in 1995. She obtained her doctorate in plant pathology, with a minor in biotechnology, from North Carolina State University, Raleigh, in 2001. Mitchum served as a postdoctoral fellow with the Developmental, Cell and Molecular Biology Group at Duke University in 2003.
For any seminar technical issues, Siddique may be reached at ssiddique@ucdavis.edu.
- Author: Kathy Keatley Garvey
"Ascaroside pheromones stimulate dispersal, a key nematode behavior to find a new food source," Kaplan says in her abstract. "For entomopathogenic nematodes (EPNs), the new food source is insects. The talk will focus on understanding the interaction between pheromone signals, dispersal and foraging strategies, and practical applications to improve the EPN's efficacy as biocontrol agents."
The seminar takes place in 122 Briggs Hall. The Zoom link: https://ucdavis.zoom.us/j/99515291076.
Seminar coordinator Shahid Siddique, a nematologist and assistant professor, Department of Entomology and Nematology, will introduce her. She will share "the development of Pheronym and the significance of its innovations to the advancement of agricultural technology," he said.
Pheronym develops nontoxic solutions for plant protection. "We use pheromones to control the behavior and development of microscopic roundworms called nematodes," the organization explains on its website. The pheromones are water soluble, which makes them suitable for seed treatment."
Kaplan related that she co-founded Pheronym to bring nematode pheromone technology to the market and to provide effective, non-toxic pest control for farmers and gardeners.
Kaplan, who grew up on a family farm in Turkey--a 40-acres hazelnut orchard--holds a doctorate in plant molecular and cell biology from the University of Florida and did postdoctoral training in natural product chemistry with a focus on isolating biologically active compounds. She worked as a scientist at NASA, the National Magnetic Field Laboratory. and the U.S. Department of Agriculture's Agricultural Research Service.
She discovered the first sex pheromone of the nematode Caenorhabditis elegans, publishing her work in Nature. She went on to discover pheromones that regulate other behaviors in both parasitic and beneficial nematodes. Kaplan discovered the first sex pheromone of the nematode Caenorhabditis elegans, publishing her work in Nature. She went on to discover pheromones that regulate other behaviors in both parasitic and beneficial nematodes. She conducted the first agricultural biocontrol experiment in space at the International Space Station in 2020.
Kaplan describes her work in her Linked-In article, A Technical Founder's Journey: An Ag-Biotech Startup CEO with a Vision:
"Being a scientist, I often have to convince people that I am the right CEO for Pheronym, an ag-biotech startup. Frequently I hear, 'You would make a great CSO.' I know I would be a great CSO, but I am the only one who can be Pheronym's CEO."
"Let's start with 'What does a startup CEO do?' Everyone knows that the CEO is the person in charge, but what does that mean for a small startup? Startup CEO's can play very different roles depending on the type, stage, and founding team. For example, digital healthcare, digital agriculture, biotechnology, consumer-facing and B2B startups all have different needs. Furthermore, a startup is expected to create something visionary that will transform the industry or create some new and novel technology. So the startup needs a CEO with a vision."
"It's always been my belief I had the vision required. In 2005, when I accepted the position to identify the model nematode's (Caenorhabditis elegans) sex pheromone, I knew how these discoveries could revolutionize agricultural pest control for nematodes. Soon after we published the work in Nature (2008), the USDA-ARS recruited me to apply this discovery to control agriculturally important nematodes. After all, pheromones had been used to control insects successfully for decades. Why not for nematodes? When I was at the USDA, I won the 2011 American Phytopathological Society Schroth Faces of the Future, Nematology Award for my vision of using pheromones to control parasitic nematodes. Then, in 2014, my article on the future of the nematode pheromone field won an essay contest sponsored by the Genetics Society of America and was published in the GSA Reporter. When I started thinking about filing patents and commercializing my discoveries, I realized that I was the only one with the knowledge, passion, and vision to make it happen." (See more.)
The Department of Entomology and Nematology seminars--some are virtual and some are in-person--are held at 4:10 p.m. on Wednesdays. Coordinator Shahid Siddique may be reached at ssiddique@ucdavis.edu for any technical issues in the Zoom seminars.
Resources:
- Women in Ag-Tech: Fatma Kaplan, Scientist-Turned-Entrepreneur Uses Pheromones to Tackle Global Food Crisis
- Women Innovators Encourage Others to Step Up as Role Models in Agriculture
- Ag-Tech Startup Gets Results from Space Nematode Experiment
- Author: Kathy Keatley Garvey
His seminar, to begin at 4:10 p.m., will be in-person and also will be broadcast live on Zoom at https://ucdavis.zoom.us/j/
"Parasitic nematodes are master manipulators of host immunity," Dillman says in his abstract. "Little is known about the identity and function of the cocktail of effectors they release during active infection. We have developed an effector discovery model using entomopathogenic nematodes and fruit flies, which we are using to identify and characterize potent modulators of insect immunity."
Dillman recently received a $1.8 million Outstanding Investigator Award from the National Institutes of Health to study the microscopic parasitic nematodes or "worms" that infect billions of humans and can cause blindness, cognitive issues and sometimes death. He focuses his research on identifying the specific proteins in a nematode's spit or venom that can trick the immune system to ignore its presence. His work on the fruit fly as his model organism could lead to treatments for autoimmune diseases in humans, such as celiac, Crohn's or inflammatory bowel diseases.
Dillman, who joined the UCR faculty in February 2015, is featured in a UC Riverside press release, "Parasitic Worm Venom Evades Human Immune System," posted July 20, 2020 on EurekAlert.
Worms Affect Billions of People. "By some estimates, nearly a quarter of the world's population is infected with various types of microscopic worms, or nematodes, with effects ranging from cognitive impairment and blindness to debilitation, elephantiasis, and death," writer Jules Berstein related. "Examples include hookworm, which thrives in the American South, causing developmental delays and anemia; and pinworms, which commonly infect children and child care workers with an itchy perianal-area rash."
She quoted Dillman: "You can have a person riddled with infection who never realized there's a 2-centimeter-long worm in their eye and thousands of parasites in their blood. The immune system never signaled something was wrong. How is that possible? We know very little about how that works."
Dillman described nematodes as "devastating parasites of humans, capable of modulating our biology in numerous ways, including suppressing our immune systems. The goal of my lab is to understand this modulation and to characterize the chemical pathways that allow it to happen. There's compelling data that parasites could even be used to treat autoimmune disorders such as Crohn's or inflammatory bowel disease. Parasitic worms are just the coolest things you could study because there are so many strange interactions, both positive and negative, that occur between the worms and their hosts."
Why Fruit Flies? Aylin Woodward of Business Insider spotlighted Dillman's work in a news story published Sept. 13, 2020. She wrote that his lab "is looking at 500 or so different types of proteins released by nematodes that infect fruit flies" and quoted Dillman as saying that "flies are cheaper and easier to work with, and the parasites that affect insects release the same proteins as those that infect mammals."
Dillman received his doctorate in 2012 from the California Institute of Technology (Caltech), a private research university in Pasadena, and then served as a postdoctoral fellow at Stanford from 2013 to 2014. He holds a bachelor's degree (2006) from Brigham Young University.
Nematologist Shahid Siddique, assistant professor, coordinates the UC Davis Department of Entomology and Nematology seminars and will introduce Dillman. He may be reached at ssiddique@ucdavis.edu.
