Alison Coomer, doctoral student in the Shahid Siddique lab

Coomer, who delivered her video presentation on “Trade-Offs Between Virulence and Breaking Resistance in Root-Knot Nematodes,” was selected one of the nine finalists in a global graduate student competition sponsored by the International Federation of Nematologists (IFN). The final round will take place later this month.  

Coomer joins only one other graduate student from the United States in the finals: Bhupendra Bhatta of the University of Idaho, Moscow. The others are from universities in England, Australia, Brazil, Ireland, Kenya, Belgium and South Africa.

IFN hosts the competition "to cultivate student academic and research communication skills, and to enhance overall awareness of nematodes and the science of nematology."

The awards will be announced before January 2022. The first-, second-, and third-place winners will be awarded busaries and plaques at the 7th  International Congress of Nematology, set May 1-6 in Antibes, France. 

For the competition, the participants were required to present only a single static slide, and not use any props or sound-effects. Judges scored them on the quality of their research presentation, ability to communicate research to non-specialists, and the 3MT slide. Each was to use lay language. 

In her presentation, Coomer began with: “Root-knot nematodes, specifically the MIG-group, consisting of Meloidogyne incognita, javanica, and arenaria, are the most damaging of the plant parasitic nematodes causing severe yield loss in over 2,000 different plant species including tomatoes. The Mi-gene, which is a resistance gene in tomato, has been used in commercial farming and has been praised for its effectiveness towards the MIG group. This gene has been cloned but the mechanisms of how it's resistance works is still unknown.” 

“We do know that with the presence of the MI gene, plants are more durable and will restrict infection and reproduction, by inducing an immune response within the plant,” Coomer pointed. “Although this resistance gene has been reliable for many decades, resistance breaking strains of root-knot nematodes have emerged threatening the tomato industry.” 

Coomer related that her research “compares two strains of the root-knot nematode M. javanica. One strain is the wildtype, which has been isolated from fields, we will refer to it as VW4. This nematode can infect tomato plants, but when the MI gene is present, the nematode is blocked from successfully infecting. The other strain is a naturally mutated version of VW4. This strain breaks the resistance provided by the MI gene and therefore infects plants that contain the MI gene. I have labeled this strain as VW5. With the help of research like mine we can stay ahead of the resistance breaking strains and prevent major crop loss in the future.” 

“Sequencing the entire genome of VW5 when compared to VW4, we can see that there is a large deletion in its genome, but we have yet to find out what genes were deleted and how important they are when it comes to infecting other plants,” she continued. “My research is focusing on what happens when we infect the resistance breaking strain, VW5 on plants not containing the MI gene.” 

In detailing her research, she said “My infection assays have been designed as displayed by the flow chart. Tomato and cucumber were used since neither variety contained the MI gene. 500 J2s were inoculated and at 34 days post inoculation, roots were harvested, and eggs were collected. After staining, galls were dissected, and nematode stage development was recorded for juveniles and females; comparisons between the two roots were made. As displayed by the graph and image, consistently, we see a reduction in the number of eggs produced in plants infected with VW5 than with VW4. The image also shows significant reduction in galls for VW5s as well. Two main objectives remain for this project: How does VW5 break MI resistance and why is VW5 less fit on plants that do not contain the MI gene. With the help of further infection assays and genomic data regarding gene presence and transcription analysis we hope to shed light on this process, identify candidate genes in action, and overall identify how the mechanism of the MI gene works.”

Coomer, a doctoral student in plant pathology with an emphasis on nematology, is working on her dissertation, "Plant Parasitic Nematode Effectors and Their Role in the Plant Defense Immune System," advised by Siddique.

Coomer, originally from the St. Louis, Mo., area, received two bachelor degrees--one in biology and the other in chemistry--in May 2020 from Concordia University, Seward, Neb., where she won the Outstanding Graduate Student in Biology Award. She served as a biology lab assistant and taught courses in general biology and microbiology. 

As a biological science aide/intern, Coomer did undergraduate research in the Sorghum Unit of USDA's Agricultural Research Service. Lincoln, Neb.  Her work included collecting, prepping and analyzing DNA, RNA and proteins to identify genes that contribute to an under- and over-expression of lignin in sorghum plants.

Parasitologist Adler Dillman of UC Riverside

Who knew that you, along with billions of other people, could be infected with undetected microscopic parasitic nematodes, or round worms? And that they spit venom?

Parasitologist Adler Dillman of UC Riverside knows. In fact, he recently received a $1.8 million Outstanding Investigator Award from the National Institutes of Health (NIH) to study these parasitic nematodes, which infect a quarter of a billion of the world's population and can cause blindness, cognitive issues and sometimes death.

Want to learn more about this research? The UC Davis Department of Entomology and Nematology has booked him as a guest speaker as part of its fall weekly seminars, coordinated by nematologist and assistant professor Shahid Siddique.

Dillman will deliver his in-person seminar, "Nematode Venom Contains Potent Modulators of Insect Immunity," at 4:10 p.m., Wednesday, Oct. 27 in 122 Briggs Hall Drive, off Kleiber Hall Drive.  It also will be broadcast live on Zoom at https://ucdavis.zoom.us/j/99515291076.

"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, who joined the UC Riverside faculty in February 2015 and is now an associate professor, 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 model organism is the fruit fly. He hopes that his research could lead to treatments for autoimmune diseases in humans, such as celiac, Crohn's or inflammatory bowel diseases.

UC Riverside featured him, his NIH grant and his research in a press release "Parasitic Worm Venom Evades Human Immune System," posted July 20, 2020 on EurekAlert. "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 of UC Riverside 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."

"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," Dlllman told her. "The immune system never signaled something was wrong. How is that possible? We know very little about how that works."

Devastating Parasites. Nematodes, he says, are "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."

Aylin Woodward of Business Insider spotlighted Dillman's work in a Sept. 13, 2020 news story headlined "A Scientist Won $1.8 Million to Study the Venom Parasitic Worms Use to Live Undetected in Our Bodies. He Thinks It Could Help Treat Celiac Disease. The Dillman lab is "looking at 500 or so different types of proteins released by nematodes that infect fruit flies," she wrote, quoting Dillman: "Flies are cheaper and easier to work with, and the parasites that affect insects release the same proteins as those that infect mammals."

"An analysis of research on this subject, published in 2017, described how the presence of nematodes and other parasites can lower inflammation in IBD and reduce the severity of multiple sclerosis, type 1 diabetes, asthma, and rheumatoid arthritis in animals," Woodward pointed out. "A 2010 study, in fact, described a patient with IBD who deliberately infected himself with a parasitic worm called a whipworm. The man's immune system started producing a type of protein crucial to healing his digestive tract, and the disease went into remission."

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. 

Shahid Siddique may be reached at ssiddique@ucdavis.edu.

Maria Silvina Fenoglio is a biologist and research scientist from Argentina

Ecologist and research scientist Maria Silvina Fenoglio of Argentina will present a virtual seminar, hosted by the UC Davis Department of Entomology and Nematology, on "Do Green Roofs Benefit Urban Arthropod Communities? Evidence from a South American City," at 4:10 p.m., Wednesday, Oct. 6. 

"Green roofs, beyond offering numerous environmental benefits, could mitigate the negative effects of urbanization on arthropods. However, the characteristics of green roofs that could favor arthropod biodiversity and ecological functioning are poorly known, especially for South American countries," Fenoglio says in her abstract. "In this talk, I will present the main results of our investigations in relation to these aspects."

Since 2018 the ecologist has served as a National Geographic explorer. She works on projects related to urban ecology and the ecology of insect communities. "I have a particular interest in the study of urban green spaces (ie. green roofs, urban gardens) as refuges for biodiversity and as providers of ecosystem services mediated by insects," she says. 

"My ultimate goal of my work is to find evidence that contributes to the development of more sustainable cities and helps to some extent to reconcile the lives of city dwellers with nature." When she's not in the lab or in the field, she enjoys yoga, painting, and spending time with her family, Camilo and Martín.

Her most recent publications include Arthropod Diversity and Ecological Processes on Green Roofs in a Semi-Rural Area of Argentina: Similarity to Neighbor Ground Habitats and Landscape Effects, published in July 2020 in the journal Landscape and urban Planning.

Coordinating the department's seminars is nematologist and assistant professor Shahid Siddique, who may be reached at  ssiddique@ucdavis.edu. 

Resources:

• National Geographic Society 
• Google Scholar

Nematologist Shahid Siddique is coordinating the Department of Entomology and Nematology's seminars for the 2021-22 academic year. (Photo by Kathy Keatley Garvey)

Nematologist and plant pathologist Shahid Siddique, assistant professor, UC Davis Department of Entomology and Nematology and coordinator of the department's seminars for the 2021-22 academic year, has announced the list of fall quarter seminars, which begin Sept. 29 and conclude Dec. 1.  

All will be held at 4 p.m. on Wednesdays, Pacific Time, and will include both in-person and virtual seminars. 

"We we have an exciting list of seminars that includes both national and international speakers," Siddique said. 

The in-person seminars will take place in Room 122 of Briggs Hall, located off Kleiber Hall Drive. These seminars will be recorded for later viewing.

Three of the seminars will be virtual. "Virtual seminars will be accomplished using the Zoom meeting software package," Siddique related. A Zoom link will be provided a week before the seminar.

First on tap will be the exit seminar of doctoral candidate Hanna Kahl of the lab of UC Davis distinguished professor Jay Rosenheim. She will speak on "Herbivory of Citrus Fruit by European Earwigs in California" at 4 p.m., Wednesday, Sept. 29. This will be an in-person seminar.

No seminar will be held Nov. 3, which conflicts with the annual meeting of the Entomological Society of America (ESA), set Oct. 31-Nov. 3 in Denver, Colo. Many faculty attend the annual meeting.

The seminars are open to all interested persons.

Siddique joined the UC Davis Department of Entomology and Nematology in July 2019 after serving as a research group leader for several years at the University of Bonn, Germany. 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."

For further information on the seminars, contact Siddique at ssiddique@ucdavis.edu.