- Author: Kathy Keatley Garvey
The Shahid Siddique laboratory was out in force on Saturday, Feb. 18 during the 12th annual UC Davis Biodiversity Museum Day.
The nematologists set up their display in the Katherine Esau Science Hall, formerly the Sciences Lab Building, and drew nearly 1000 visitors, the most ever.
“BioDiv Day went really well,” said Siddique, an assistant professor of nematology, UC Davis Department of Entomology and Nematology. “A lot of people took interest in getting information about dog heartworms and root-knot nematodes infecting tomatoes. Some people said that nematodes were their favorite stop for BioDiv Day. We had 906 visitors in total and a vast majority of them were kids with family.”
Participating with Siddique were his graduate students Alison Coomer, Veronica Casey, Pallavi Shakya, and Ching-Jung Lin, and professor emeritus Valerie Williamson of Plant Pathology.
The Siddique lab focuses 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," Siddique says, "but also to use this knowledge to provide new resources for reducing the impact of nematodes on crop plants in California."
- Celery infected with root-knot nematodes
- Anisakis nematodes from a Minke whale stomach
- Heart of a dog infected with heartworms (Dirofilaria immitis)
- Parasitic nematodes (Baylisascaris transfuga) isolated from the stomach of a bear
- White-tailed deer eye infected with parasitic nematodes (Thelazia spp.)
- Sugar beet infected with root-knot nematodes
- Dog ascaris (Toxocara canis) cause of visceral larva migrans
- Common parasitic worms of human (Ascaris lumbricoides) cause of Ascaris isolated from human intestine
- Dog intestine infected with whipworms
- Horse stomach parasite community including 1) Parascaris 2) Tapeworms 3) Botfly larvae
- Yam infected with root-knot nematode
- Tomato root infected with root-knot nematode
- Adult raccoon roundworms
- Filarial nematodes (Onchocerca volvulus) cause of Onchocerciasis river blindness
- Zoonotic hookworms (Ancylostoma caninum)
- Ascaris lumbricoides (common parasitic worms of human)
- Tree swallow infected with Diplotriaena nematode
- Sugar beet infected with cyst nematode (Heterodera schachtii)
- Grape roots infected with Root-knot nematodes
- Mormon crickets infected with horsehair worms (Gordius robustus)
- Peach roots infected with root-knot nematodes
- Anisakis nematodes from fish intestine
- Hysterotahylaciun nematodes isolated from fish
- Pinworms isolated from human intestine
- Whipworms isolated from human Intestine
- Anisakis nematodes isolated from seals
- Adult dog heartworms
BioDiv Day, founded by the Bohart Museum, is traditionally held on Presidents' Day weekend. Some 3000 attended this year's event, estimated chair Tabatha Yang, education and outreach coordinator of the Bohart Museum. The "Super Science Day" is free and family friendly. Yang is encouraging donations to help pay expenses; access the UC Davis crowdfunding page.
The Esau Science Hall is newly named for UC Davis professor emeritus Katherine Esau, 1898-1997. Internationally known as one of the most influential plant biologists and professors in history, Esau is lauded for her pioneering work on plant anatomy and structure that laid the foundation for much of today's research in the field. She won the National Medal of Science awarded by then president George Bush.
Esau was born in Ukraine. Her family fled to Berlin after World War I and then emigrated to the United States. She joined the UC Davis faculty after receiving her doctorate in 1931. She was elected to the National Academy of Sciences in 1957, only the sixth woman to receive that honor. Following her retirement, she relocated to UC Santa Barbara in 1965. According to Wikipedia, she continued research well into her 90s, publishing a total of 162 articles and five books.
Esau died June 4, 1997 at age 99 in Santa Barbara. A New York Times article quoted Peter Raven, director of the Missouri Botanical Garden: "She absolutely dominated the field of plant anatomy and morphology for several decades. She set the stage for all kinds of modern advances in plant physiology and molecular biology."
In 1982, at age 84, Esau delivered her final UC Davis lecture, covering plasmodesmata. In 1988, she donated $648,000 to UC Davis to establish an endowment to fund plant research fellowships in perpetuity. As of 2020, the endowment's market value has increased by almost six times its original amount, standing at $3.7 million, according to a UC Davis news story.
/span>- Author: Kathy Keatley Garvey
Her seminar, both in-person and virtual, begins at 4:10 p.m., Wednesday, Nov. 16 in 122 Briggs Hall. The Zoom link: https://ucdavis.zoom.us/j/95882849672.
Nematologist Shahid Siddique, assistant professor, UC Davis Department of Entomology and Nematology, is the host.
"Meloidogyne chitwoodi is a root-knot nematode often found in potato growing regions of Northwestern United States," Gleason says in her abstract. "It is a nematode that can infect both potato roots and tubers. In the case of tuber infections, it causes small pimple-like blemishes on the skin, giving the potato a rough, bumpy appearance. Unfortunately, there are no commercially available potato cultivars that are resistant to M. chitwoodi."
"The Gleason lab is undertaking several different lines of research to develop novel tools to combat these nematodes," she said. "For example, we characterize nematode effectors, which give us information about how the nematodes avoid or suppress the plant immune system. In addition, we are developing molecular markers to distinguish the different M. chitwoodi populations that differ in host range and virulence. On the plant side of the interaction, we are studying nematode resistance in potato, including resistance triggered by the potato defense elicitor called Pep1."
Gleason, who joined the WSU faculty in 2016, holds a doctorate in biochemistry and molecular biology from UC Davis (2003). She served as postdoctoral fellow, Disease and Stress Biology, John Innes Centre, Norwich UK (2003-2006), postdoctoral fellow, Plant Industry, CSIRO, Perth, Australia (2006-2010); and as junior professor in the Department of Plant Molecular Biology and Physiology, Georg-August-University Göttingen, Germany (2011-2016).
From her WSU website: "My research centers around plant parasitic nematodes and primarily focuses on root-knot nematodes and their interactions with host plants. These small roundworms are soil borne pathogens that can infect most vascular plants. The root infections cause damage that affects water and nutrient uptake, and this can lead to dramatically reduced crop yields. In order to develop new strategies to combat nematodes, my group studies root-knot nematode secretions that are released into the plant and manipulate host defenses and signaling pathways. One focus of study is on the root-knot nematode Meloidogyne chitwoodi, a serious pathogen of potatoes in the region. We are interested in identifying novel M. chitwoodi pathogenicity genes required for successful potato infection. We are also working to dissect the defense responses triggered during infection of nematode-resistant potatoes. My lab uses a variety of experimental approaches, such as gene expression analyses, generation and characterization of transgenic plants, and heterologous expression of nematode genes in bacteria, to increase our knowledge of the plant/nematode interaction at the molecular level."
Emily Meineke, assistant professor of urban landscape entomology, UC Davis Department of Entomology and Nematology, coordinates the department's seminars for the 2022-23 academic year. All 11 seminars will take place both person and virtually at 4:10 p.m. on Wednesdays in Room 122 of Briggs Hall except for the Nov. 9th and Dec. 7th seminars, which will be virtual only, she said. (See list of seminars)
For further information on the seminars or to resolve any technical difficulties with Zoom, contact Meineke at ekmeineke@ucdavis.edu.
- 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.
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- 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.