In the spotlight: the newly discovered beech leaf disease caused by the nematode, Litylenchus crenatae mccannii. First found in Ohio in 2012 and now spreading to at least 10 other states, plus Canada, the lethal disease kills the native American beech as well as the commonly planted European beech, scientists say. There is no known cure. 

Enter researcher Paulo Vieira, a plant pathologist, molecular biologist and nematologist with USDA's Agricultural Research Service (USDA-ARS), Beltsville, MD.

He will speak on "Beech Leaf Disease: An Emergent Threat to Beech Forest Ecosystems in North America" at a virtual seminar hosted by the UC Davis Department of Entomology and Nematology, announced host and nematologist Shahid Siddique. It is set for 4:10 p.m., Wednesday, May 17. The Zoom link: 
https://ucdavis.zoom.us/j/95882849672.

"The beech leaf disease nematode, Litylenchus crenatae mccannii, is recognized as a newly emergent nematode species that causes beech leaf disease (BLD) in beech trees (Fagus spp.) in North America," Vieira says in his abstract. "Since the first report of BLD on Fagus grandifolia in Ohio in 2012, the disease has rapidly spread to other states and Canada. This nematode has been so far reported in Pennsylvania, New York, Connecticut, Massachusetts, Maine, Michigan, Rhode Island, New Jersey, West Virginia, and Virginia, as well as Ontario. Leaf symptoms include swelling and darkening of interveinal tissues as well as chlorosis, while tissue necrosis and leaf curling occur at later stages of the disease. As a result, mortality of nematode infected understory beech trees has been reported after several years of infection in the United States. The fast dissemination of this nematode can impose a dramatic effect on beech forest ecosystems and natural diversity in North America."

Vieira says that "Little information on the molecular and cellular interaction between this nematode and its hosts is available. To advance our understanding into this unknown host- nematode system, we investigated the cytological aspects of this interaction using bright-field and scanning electron microscopy. Our data reveal that these nematodes can induce morphological changes in both bud and leaf tissues, which so far seem unique in the Nematoda phylum. These cellular changes ultimately provide the necessary nutrients for completion of the nematode life cycle, while dramatically affecting bud and leaf morphology. In addition, we used Illumina mRNA sequence analysis of a mixed stage population to obtain insight into the transcriptome of this nematode. Gene comparative analyses were combined to select a list of candidate effector/parasitism genes. Spatial expression of transcripts within the esophageal glands of L. crenatae mccannii by in situ hybridization validated a list of pioneer effectors novel to this species and across the Nematoda phylum. These analyses provide additional data for understanding the mode of parasitism of this newly emergent plant-parasitic nematode."

Vieira, who joined USDA-ARS in November 2021, holds a master's degree (2007) in plant pathology, phytopathoogy from the University of Évora, Portugal, and a doctorate (2012 in plant pathology, plant-nematode interaction from the  University of Nice Sophia-Antipolis and Institute Sophia Agrobiotech, France. His resume includes postdoctoral researcher at the University of Évora (2012-2013) and USDA (2013-2015). Vieira served as a researcher in molecular biology at Virginia Tech for eight years before joining USDA-ARS in Beltsville.

Vieira's current research interests:

• Identification and functional analyses of effectors of plant-parasitic nematodes
• Genomics and transcriptomics of plant-parasitic nematodes, with a particular focus on migratory nematodes
• Plant-nematode interaction studies using cell and molecular biology approaches

Department seminar coordinator is urban landscape entomologist Emily Meineke,  assistant professor.   For technical issues regarding Zoom connections, she may be reached at ekmeineke@ucdavis.edu. (See complete list of spring seminars.)

Related Resources:

First report of the beech leaf disease nematode Litylenchus crenatae mccannii (Nematoda: Anguinidae) in Michigan (Plant Disease journal, Nov. 22, 2022)
Paulo Vieria: Google scholar and Twitter accounts

What do you know about nematodes and what would you like to learn? 

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."

A list of what visitors saw:

1. Celery infected with root-knot nematodes
2. Anisakis nematodes from a Minke whale stomach
3. Heart of a dog infected with heartworms (Dirofilaria immitis)
4. Parasitic nematodes (Baylisascaris transfuga) isolated from the stomach of a bear
5. White-tailed deer eye infected with parasitic nematodes (Thelazia spp.)
6. Sugar beet infected with root-knot nematodes
7. Dog ascaris (Toxocara canis) cause of visceral larva migrans
8. Common parasitic worms of human (Ascaris lumbricoides) cause of Ascaris isolated from human intestine 
9. Dog intestine infected with whipworms
10. Horse stomach parasite community including 1) Parascaris 2) Tapeworms 3) Botfly larvae
11. Yam infected with root-knot nematode
12. Tomato root infected with root-knot nematode
13. Adult raccoon roundworms
14. Filarial nematodes (Onchocerca volvulus) cause of Onchocerciasis river blindness
15. Zoonotic hookworms (Ancylostoma caninum)
16. Ascaris lumbricoides (common parasitic worms of human) 
17. Tree swallow infected with Diplotriaena nematode
18. Sugar beet infected with cyst nematode (Heterodera schachtii)
19. Grape roots infected with Root-knot nematodes
20. Mormon crickets infected with horsehair worms (Gordius robustus)
21. Peach roots infected with root-knot nematodes
22. Anisakis nematodes from fish intestine
23. Hysterotahylaciun nematodes isolated from fish
24. Pinworms isolated from human intestine
25. Whipworms isolated from human Intestine
26. Anisakis nematodes isolated from seals
27. Adult dog heartworms

The 12th annual Biodiversity Museum Day showcased 11 museums and collections: the Anthropology Museum, Arboretum and Public Garden, Bohart Museum of Entomology, Botanical Conservatory, California Raptor Center, Center for Plant Diversity, Nematode Collection, Marine Invertebrate Collection, Museum of Wildlife and Fish Biology, Paleontology Collection and the Phaff Yeast Culture Collection.

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.

It's beginning to look a lot like...UC Davis Biodiversity Museum Day!

The 12th annual event, set Saturday, Feb. 18 on the UC Davis campus, will showcase 11 museums or collections. Known as a "Super Science Day" and a day to chat with scientists and check out the displays, it's free and family friendly.

All sites are within walking distance of the campus except for the Raptor Center, which is two miles away on Old Davis Road. Maps and directions are posted on the website. The maps also will be available the day of the event.

The UC Davis Biodiversity Museum Day is traditionally held during Presidents' Weekend. The list of the 11 museums or collections:

• Anthropology Museum, 328 Young Hall and grounds, noon to 4 p.m.
• Arboretum and Public Garden, Habitat Gardens in the Environmental GATEway, adjacent to the Arboretum Teaching Nursery on Garrod Drive,  9 a.m. to 1 p.m.
• Bohart Museum of Entomology, Room 1124 and main hall of the Academic Surge Building, Crocker Lane, 9 a.m. to noon and 1 to 4 p.m.
• Botanical Conservatory, the greenhouses along Kleiber Hall Drive, 11 a.m. to 3 p.m.
• California Raptor Center, 340 Equine Lane, off Old Davis Road, 9 a.m. to 3 p.m. 
• Center for Plant Diversity, Sciences Laboratory Building/Esau Science Hall, off Kleiber Hall Drive, 11 a.m. to 3 p.m.
• Nematode Collection, Sciences Laboratory Building/Esau Science Hall, off Kleiber Hall Drive, 9 am. to 3 p.m..
• Marine Invertebrate Collection, Sciences Laboratory Building/Esau Science Hall, off Kleiber Hall Drive, 9 am. to 3 p.m.
• Museum of Wildlife and Fish Biology, Room 1394, Academic Surge Building, 455 Crocker Lane, 10 a.m. to 2 p.m.
• Paleontology Collection, Department of Earth and Planetary Sciences, 1309 Earth and Physical Sciences Building, 434 LaRue Road, 12 noon to 4 p.m.
• Phaff Yeast Culture Collection, Robert Mondavi Institute Brewery and Food Processing facility, Old Davis Road, 10 a.m. to 2 p.m. (See news story) 

Tabatha Yang, education and outreach coordinator of the Bohart Museum of Entomology, chairs the UC Davis Biodiversity Museum Day and is a founder of the event. 

Those who wish to donate to the UC Davis Biodiversity Museum Day can access the crowdfunding site. Donations may be made in honor or memory of someone, said Yang. A donor wall is online.

For more information, see the Biodiversity Museum Day website.

Mark your calendars! 

The 12th annual UC Davis Biodiversity Museum Day, billed as "A Day to Celebrate Science," is set for Saturday, Feb. 18. Traditionally held during Presidents' Day Weekend, the event is free and family friendly. Parking is also free.

Biodiversity Museum Day chair Tabatha Yang, education and outreach coordinator for the Bohart Museum of Entomology, today announced that 11 museums or collections on campus will showcase their work:

• Anthropology Museum, 328 Young Hall and grounds, noon to 4 p.m.
• Arboretum and Public Garden, Shields Oak Grove, alongside the Vet School,  Garrod Drive on campus, 9 a.m. to 1 p.m.
• Bohart Museum of Entomology, Room 1124 and Main Hall of the Academic Surge Building, Crocker Lane, 9 a.m. to noon and 1 to 4 p.m.
• Botanical Conservatory, the Greenhouses along Kleiber Hall Drive, 11 a.m. to 3 p.m.
• California Raptor Center, 340 Equine Lane, off Old Davis Road, 9 a.m. to 3 p.m. (tentative)
• Center for Plant Diversity, Sciences Laboratory Building, off Kleiber Hall Drive, 11 a.m. to 3 p.m.
• Nematode Collection, Sciences Laboratory Building, off Kleiber Hall Drive, 9 am. to 3 p.m.
• Marine Invertebrate Collection (Sciences Laboratory Building), noon to 3 p.m.
• Museum of Wildlife and Fish Biology, Room 1394, Academic Surge Building, Crocker Lane, 10 a.m. to 2 p.m.
• Paleontology Collection, Earth and Physical Sciences Building, 434 LaRue Road, to be determined
• Phaff Yeast Culture Collection, Robert Mondavi Institute Brewery, Winery and Food Processing facility, 10 a.m. to 2 p.m. (See news story)

During the COVID-19 pandemic, however, the 2022 Biodiversity Museum Day took place March 6 in the UC Davis Conference Center and drew some 1000 visitors. In 2023, it's back home to the individual departments where scientists will be on hand to greet visitors and answer questions.

Biodiversity Museum Day is considered a great opportunity to celebrate the diversity and variety of species on planet Earth and learn about the research being done at UC Davis. The event is also considered a great opportunity for scientists-to-be to consider their career options. Some of the museums and collections are open to the public only on Biodiversity Museum Day, Yang said.