- Author: Kathy Keatley Garvey
YSP is a six-week summer residential program that introduces several dozen high-achieving high school students to original research within the fields of biological, agricultural, environmental, or the natural sciences.
The lab of nematologist Shahid Siddique, associate professor, UC Davis Department of Entomology and Nematology, mentored Anderson Van Wang, a 17-year-old senior at California City High School, Kern County, and Mason Walline, now 18, and a senior at Harvard-Westlake School, Los Angeles.
Anderson worked with doctoral student Veronica Casey of the Siddique lab to investigate the effects of bacterial supernatant to plant parasitic nematodes. Walline worked with Ching-Jung Lin, a doctoral student in the Siddique lab and the lab of Professor Gitta Coaker, Department to Plant Pathology, to transiently express nematode proteins in the plant system.
Also mentoring them were Siddique and lab members Bardo Castro Esparza, a postdoctoral fellow; and Alison Blundell, a doctoral candidate.
Each scholar receives five units of University Group Study Credit. All work is graded. Not only do they engage in university-level course work, attend lectures, and work on their projects, but they experience “the climate and culture of living and learning on a university campus,” according to YSP director Megan Bettis.
Mason won second-place honors in the research competition, the "YSP Summer Slam" (Elevator Pitch or short-version), competing with some 35 other students. His topic: “Advancing Transient Nematode Peptide Expression: A Pathway to Co-Immunoprecipitation Optimization." Said Lin: "He delivered a compelling two-minute presentation with a single slide. His expertise and professionalism were evident, and he was awarded second-place among the six finalists."
Neither plans a career as a nematologist, but what an amazing program and what an amazing experience.
“Working in Dr. Shahid Siddique's lab was an absolutely amazing experience," Anderson said.
“The lab environment was very high energy and upbeat," said Mason. "I'm so glad I was a temporary part of such a strong and inclusive community.”
And they learned a lot about nematodes.
Siddique defines plant-parasitic nematodes as "destructive pests causing losses of billions of dollars annually. Economic, health, and environmental considerations make natural host plant resistance a preferred strategy for nematode control, but there are limitations to this approach. In many cases, the resistance conferred by resistance genes is partial, and some of the nematodes are able to survive. Similarly, nematode resistance genes are often effective against only one or a few species, whereas plants are exposed to several pathogens in the field. Another concern is the emergence of pathotypes that can overcome resistance. In view of all these limitations, it is important to identify additional mechanisms and tools that can be used to develop novel and sustainable approaches to the management of nematodes."
The 2025 YSP summer program is set June 22-Aug. 2, with applications opening Jan. 15. High school students can apply at https://ysp-app.ucdavis.edu/.
- Author: Kathy Keatley Garvey
Two UC Davis nematology doctoral students were invited to give research presentations at the international Society of Nematologists' conference in Park City, Utah and they excelled.
Meet the two young women: Alison Blundell, a doctoral candidate who was invited to compete in a 12-minute student oral competition to discuss her research on root-knot nematodes, and doctoral student Veronica Casey, invited to share her research on "Pathogenic Hitchhikers."
Their major professor, Shahid Siddique, encourages his students to participate in the Society of Nematologists (SON), an international organization that advances the science of nematology in both its fundamental and economic aspects.
Blundell, who anticipates receiving her doctorate in 2026, won second place in the international competition with her presentation, “Overcoming Resistance: Unraveling the Mechanisms Behind Root-Knot Nematode Evasion of Tomato Mi-Gene.” She received a $250 prize.
Blundell researches plant-parasitic nematodes specifically root-knot nematodes, and their molecular mechanism to defend against plant immune systems. In her abstract, she wrote: "Root-knot nematodes (RKNs) are among the most devastating pathogens of crops, causing substantial yield and economic losses worldwide. These parasitic organisms can infect over a hundred different plant species and can evade plant defense mechanisms by secreting a concoction of effectors. For decades, the Mi-1 resistance gene has been effective in detecting and inhibiting RKNs in tomatoes. However, the underlying mechanisms by which Mi-1 detects these pathogens remain largely unknown. In recent years, resistance-breaking populations have emerged in both greenhouse and field settings, posing a threat to the potency and effectiveness of the Mi-1 gene and, consequently, the tomato industry. "
"We used two strains of M. javanica, one strain VW4, which is recognized by Mi-1, and another strain, VW5, which was selected from VW4 and can overcome resistance mediated by Mi-1," Blundell explained. "Utilizing the newly constructed reference genome for M. javanica (VW4), we compared genomes of VW4 and VW5 and identified an approximately 50 kb region that is present in VW4 but missing in VW5. This missing region contains seven protein-coding genes, three of which encode putative effectors and are currently being tested as potential avirulence genes for Mi-1."
"In addition, we have conducted a series of infection assays on different host plants lacking Mi-1, and the results revealed a significantly lower egg count in VW5 when compared to VW4. We plan to expand these assays by testing additional M. javanica resistance-breaking strains collected from fields all over California to determine if this trade-off is consistent across other strains. Overall, our results suggest that although VW5 can overcome Mi-1, there is a trade-off in the form of compromised reproduction. This research helps to better understand the mechanism and components of Mi-1 and develop strategies for addressing resistance-breaking populations."
Pathogenic Hitchhikers
Doctoral student Veronica Casey delivered her invited presentation on “Pathogenic Hitchhikers: Investigating the Synergy of Bacteria and Nematodes on Plant Health.”
a"In the vast scope of soil ecology, plant-parasitic nematodes can forge alliances with other microbial adversaries, such as the disease complex formed between nematodes and bacterial wilt-causing Ralstonia spp.," Casey wrote in her abstract. "These disease complexes exacerbate disease symptoms and yield losses. Plant-parasitic nematodes are microscopic roundworms that cause approximately $100 billion in yield loss a year, and most of the damage is attributed to root-knot nematodes (RKNs; Meloidogyne spp.). Bacterial wilt is caused by multiple Ralstonia species, namely Ralstonia pseudosolanacearum, R. solanacearum, and R. sygzii that enter the plant's roots to colonize its vascular system. Prior to Ralstonia infection, RKN infection may facilitate bacterial disease by increasing access to the vascular tissue."
"However, little research has been conducted to elucidate the molecular details of this interaction," Casey pointed out. "Previous reports of RKN and Ralstonia spp. in the field hypothesized that the infection was due to root wounding and physiological changes. In this study, I will determine the nature of the interaction between Ralstonia and nematodes at both ecological and molecular levels. This research project will explore the hypotheses that 1) Ralstonia adheres to the cuticle of nematodes using specialized appendages called pili and 2) de novo xylem formation in the galls increases Ralstonia transport into the plant. A common strategy for preventing nematode infection is by using resistant plant cultivars."
"However, resistance-breaking nematode populations have arisen and we plan to utilize resistance-breaking nematodes, which are most likely to interact with bacterial wilt in the field," Casey noted. "This presentation will report on the attachment and greenhouse experimental results of the RKN-Ralstonia complex. The escalation of climate change is leading to increased instances of pathogenicity; therefore, it is crucial to uncover disease complexes which can have monumental consequences on food security. A meticulous study into the nematode and Ralstonia disease complex will support the management of these damaging pathogens across the world."
Blundell and Siddique also delivered invited presentations in the illustration workshop. Blundell gave her presentation on "Become an Illustrator Mender Simply by Using BioRender," and Siddique, "Doodle Your Data: Adobe Illustrator for Nematodes."
Other lab mates from the Siddique lab also participated in the SON meeting. (See news story). In the ecology session, doctoral candidate Chris Pagan participated from the UC Davis lab of distinguished professor Steve Nadler, former chair of the Department of Entomology and Nematology. Pagan's presentation: "Nematode Community Structure in the Rhizopsheres of Southern California Creosote (Larrea trientata).”
Of note, Blundell and Casey were among the four graduate students from the Siddique lab who received travel awards. Blundell won a Corteva award and Casey, a Certis award. Also receiving travel awards wer Ching-Jung Lin, a Bayer CropScience award and Romnick Latina, a N. A. Cobb Foundation award.
Honorary Member. At the 2024 conference, UC Davis distinguished professor emeritus Howard Ferris was selected a Honorary Member, the highest award that SON offers. (Feature story pending; wait 'til you hear his exciting life story!)
UC Davis nematologists are already looking forward to the next annual meeting: July 13-17 in Victoria, British Columbia, Canada. Meanwhile, you can chat one-on-one with them at the annual UC Davis Biodiversity Museum Day, usually held in February on the UC Davis campus. It traditionally featuring a dozen or so UC Davis museums. Student nematologists are spotlighted on the current website.
- Author: Kathy Keatley Garvey
The Nematode Collection, showcased in the Katherine Esau Science Hall, drew hundreds of visitors wanting to know more about the organism commonly known as "roundworm."
Nematologist Shahid Siddique, associate professor, UC Davis Department of Entomology and Nematology, and Alison Blundell, a doctoral candidate in Plant Pathology, coordinated the displays.
The collection highlighted both animal and plant parasitic nematodes. Visitors examined the preserved specimens and watched the movement of live free-living C. elegans (good nematodes) via a microscope.
Among the displays:
Animal Parasitic Nematodes: Anisakis nematodes from a Minke whale stomach, heart of a dog infected with heartworms; dog intestine infected with whipworms; a horse stomach parasite community including Parascaris, tapeworms and botfly larvae; adult raccoon roundworms; tree swallow infected with Diplotriaena nematode; and whipworms isolated from the human intestine.
Plant Parasitic Nematodes: Celery, sugar beet, and yam infected with root-knot nematodes; fresh tomato root infected with root-knot nematodes, and a mustard plant infected with cyst nematodes.
"Plant-parasitic nematodes are destructive pests causing losses of billions of dollars annually," Siddique writes on his website. "Economic, health, and environmental considerations make natural host plant resistance a preferred strategy for nematode control, but there are limitations to this approach. In many cases, the resistance conferred by resistance genes is partial, and some of the nematodes are able to survive. Similarly, nematode resistance genes are often effective against only one or a few species, whereas plants are exposed to several pathogens in the field. Another concern is the emergence of pathotypes that can overcome resistance. In view of all these limitations, it is important to identify additional mechanisms and tools that can be used to develop novel and sustainable approaches to the management of nematodes."
Research in 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 but also to use this knowledge to provide new resources for reducing the impact of nematodes on crop plants in California," he says.
The 13th annual Biodiversity Museum Day featured 10 museums or collections: Anthropology Museum, Arboretum and Public Garden, Bohart Museum of Entomology, Botanical Conservatory, California Raptor Center, Center for Plant Diversity, Nematode Collection, Museum of Wildlife and Fish Biology, Paleontology Collection, and Phaff Yeast Culture Collection.
Chairing the UC Davis Biodiversity Museum Committee: Tabatha Yang, education and outreach coordinator of the Bohart Museum.
- Author: Kathy Keatley Garvey
You'll see specimens and get to talk to nematologists during the 13th annual UC Davis Biodiversity Museum Day on Saturday, Feb. 10. The free and family friendly event, known as “Super Science Day," will showcase 10 museums or collections.
The nematode collection, headed by Shahid Siddique, associate professor, Department of Entomology and Nematology, will be open from 10 a.m. to 2 p.m.. in the Katherine Esau Science Hall, off Kleiber Hall Drive.
“Our collection will highlight both animal and plant parasitic nematodes,” said graduate student Alison Blundell of the Siddique lab. “We will have mostly all preserved specimens from our nematode collection for the community to look at, and some live free-living (good nematodes) under the microscope for viewing. We hope to inspire people to understand what a nematode is and how they can impact their own lives!”
“We will have preserved specimens of common crops and plants you see in your garden infected with nematodes,” she added. “We also plan to have live C. elegans (Caenorhabditis elegans) to watch how they move through the environment. Come talk to experts in the field and see why worms are cool and you will receive a cool magic worm to take home as well!”
What visitors can expect to see:
- Anthropology Museum, 328 Young Hall and grounds, open from noon to 4 p.m.
- Arboretum and Public Garden, Habitat Gardens in the Environmental GATEway, adjacent to the Arboretum Teaching Nursery on Garrod Drive, 10 a.m. to 2 p.m.
- Bohart Museum of Entomology, Room 1124 and main hall of the Academic Surge Building, 455 Crocker Lane, 10 a.m. to 2 p.m.
- Botanical Conservatory, the greenhouses along Kleiber Hall Drive, 10 a.m. to 2 p.m.
- California Raptor Center, 1340 Equine Lane, off Old Davis Road, 9 a.m. to 3 p.m.
- Center for Plant Diversity, Katherine Esau Science Hall off Kleiber Hall Drive, 10 a.m. to 2 p.m.
- Nematode Collection (part of the UC Davis Department of Entomology and Nematology), Katherine Esau Science Hall, off Kleiber Hall Drive, 10 am. to 2 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, 10 a.m. to 2 p.m.
- Phaff Yeast Culture Collection, Robert Mondavi Institute Brewery and Food Processing facility, Old Davis Road, 10 a.m. to 2 p.m.
Last year's Biodiversity Museum Day drew some 4000 people, said chair Tabatha Yang, education and outreach coordinator for the Bohart of Museum of Entomology who co-founded the event.
"Traditionally UC Davis Biodiversity Museum Day is a free, educational event for the community where visitors get to connect with UC Davis scientists from undergraduate students to staff to emeritus professors," Yang posted on the website. "In 2021, we pivoted to a month-long, virtual program. In 2022, also because of COVID regulations, we held the event in the UC Davis Conference Center as an 'expo.' In 2023 and again this year in 2024 we continued to maintain that spirit and were excited to have the event in our near our home departments."
See Biodiversity Museum Day website for more information and to download a map, which shows free parking spaces.
- Author: Kathy Keatley Garvey
Dillman, professor and chair of the UCR Department of Nematology, will share his research in a presentation titled "Nematode Parasitism of Insects with Toxic Cardenolides," hosted by the UC Davis Department of Entomology and Nematology at 4:10 p.m., Monday, Jan. 8.
His seminar will be in Room 122 of Briggs Hall and also will be on Zoom. The Zoom link: https://ucdavis.zoom.us/j/95882849672. Associate professor and nematologist Shahid Siddique of the Department of Entomology and Nematology is the host.
Dillman holds a bachelor's degree in microbiology from Brigham Young University (2006) and a doctorate in genetics (2013) from the California Institute of Technology.
The abstract of his UC Davis seminar: 
Known as an excellent investigator and teacher, Dillman won the 2022 UCR Chancellor's Award for Excellence in Undergraduate Research and Creative Achievement; the 2021 Award for Excellence in Teaching from the Society of Nematologists, and a 2020 Outstanding Investigator Award, Maximizing Investigators' Research Award (MIRA).
Check out his lab page that details his research and his guest spot on an episode on the podcast Something Offbeat. He he discussed a scientific article on a case of Ophidascaris robertsi infection in a human brain.
Seminar coordinator is Brian Johnson, associate professor, UC Davis Department of Entomology and Nematology. For Zoom technical issues, he may be reached at brnjohnson@ucdavis.edu. The complete list of winter seminars will be posted soon.
