- Author: Kathy Keatley Garvey
His seminar, to be both in-person and virtual, begins at 4:10 p.m., Pacific Time in 122 Briggs Hall. The Zoom link is https://ucdavis.zoom.us/j/99515291076.
"From the moment of initial encounter with an insect herbivore, a suite of inducible plant defenses are triggered; however, the molecular mechanisms for recognition and response are not highly studied," Steinbrenner writes in his abstract. "Specific molecular patterns from insects can serve as elicitors of defense responses on host plants, but precise receptors mediating such responses have remained elusive. We recently identified a cell surface receptor, Inceptin Receptor (INR), which detects a set of ubiquitous peptide fragments found in the oral secretions of Lepidopteran larval herbivores. INR is specific to select legume species and may structure insect host range across this plant family. We hypothesize that INR serves as a recently evolved and highly potent mechanism to perceive a specific danger signal, above and beyond cues associated with generic tissue damage. I will discuss our recent transcriptiomic characterization of inceptin responses in bean and cowpea, highlighting strong anti-herbivore defense outputs which occur after inceptin treatment but not wounding alone. I will also compare plant responses to herbivory with well-characterized pathways mediating recognition of microbial pathogens."
Steinbrenner focuses his research on cell and molecular biology, genetics and genomics, and plant biology. He holds a bachelor of science degree in biology from Tufts University (2010) and a doctorate from UC Berkeley in plant biology (2015). He was awarded a Howard Hughes Medical Institute Postdoctoral Fellowship of $180,000 in 2016 and studied with Eric Schmelz at UC San Diego.
The Steinbrenner lab studies the molecular bases of plant immunity to pathogens and pests. "We are specifically interested in recognition and signaling functions of cell surface receptors and evolutionary processes driving novel immune specificity," he says on his website.
Steinbrenner served as the lead author of a paper published Nov. 23, 2021 in the Proceedings of the National Academy of Sciences on how cowpea plants detect that they're being eaten by caterpillars. In the article, A Receptor-Like Protein Mediates Plant Immune Responses to Herbivore-Associated Molecular Patterns, scientists from the University of Washington and UC San Diego reported that the cowpea plants harbor receptors on the surface of their cells that can detect a compound in caterpillar saliva and initiate anti-herbivore defenses.
"Despite chemical controls, crop yield losses to pests and disease generally range from 20-30 percent worldwide," Steinbrenner related in a University of Washington news release. "Yet many varieties are naturally resistant or immune to specific pests. Our findings are the first to identify an immune recognition mechanism that sounds the alarm against chewing insects.”
Wrote UW science writer James Urton: "The team showed that, in response to both leaf wounds and the presence of a protein fragment specific to caterpillar saliva, the cowpea's INR protein boosts the production of ethylene, a hormone that plants often produce in response to munching by herbivores and other types of environmental stress. The protein fragment in caterpillar spit that elicited this response, Vu-IN, is actually a fragment of a cowpea protein, which gets broken down by the caterpillar as it dines on cowpea leaves." (See full article.)
Nematologist Shahid Siddique, assistant professor, UC Davis Department of Entomology and Nematology, coordinates the Wednesday seminars. For any Zoom technical issues, contact him at ssiddique@ucdavis.edu.
- Author: Kathy Keatley Garvey
He will speak in person at 4:10 p.m. in 122 Briggs Hall. For those unable to attend, his lecture also will be on Zoom; link to https://ucdavis.zoom.us/j/99515291076.
"Plants interact with incredibly diverse groups of animals including plant-feeding insects and nematodes as well as their natural enemies," Groen says in this abstract. "These interactions are influenced by toxic defensive chemicals that plants make. In my talk, I will focus on how plants evolved variation in production of these defensive chemicals and how animal parasites in turn evolved mechanisms enabling them to handle such toxins."
He recently authored an article in the journal Current Biology on "Convergent Evolution of Cardiac-Glycoside Resistance in Predators and Parasites of Milkweed Herbivores."
From EurekaAlert: "Scientists now understand how certain animals can feed on picturesque, orange monarch butterflies, which are filled from head to abdomen with milkweed plant toxins. In high enough concentrations, milkweed can kill a horse, or a human. To be able to eat this plant, monarchs evolved a set of unusual cellular mutations. New UC Riverside research shows the animals that prey on monarchs also evolved these same mutations. A Current Biology journal article describes the research that revealed these mutations in four types of monarch predators — a bird, a mouse, a parasitic wasp, and a worm."
Groen, who joined the UC Riverside faculty in July 2021 following his postdoctoral research position (2014 to 2021) in the Noah Whiteman laboratory, Department of Ecology and Evolutionary Biology, University of Arizona, focuses his research on "understanding molecular mechanisms of adaptation in the context of species interactions and fluctuating environmental conditions."
A native of the Netherlands, he received his bachelor's degree and masters degree in biology from Wageningen University, Netherlands, and his doctorate in plant sciences from the University of Cambridge, UK.
Groen served as a visiting researcher from 2007 to 2008 in the Department of Multi-Trophic Interactions, Netherlands Institute of Ecology, and as a visiting researcher from 2008 to 2012 in the Department of Organismic and Evolutionary Biology, Harvard University.
"Growing up in The Netherlands, I became fascinated with plants and their responses to ever-changing environmental conditions while working as a 'ziekzoeker' in tulip fields outside of school hours," he writes in an author profile on the American Society of Plant Biologists website. The site featured him as the first author of “Evolutionary Systems Biology Reveals Patterns of Rice Adaptation to Drought-Prone Agro-Ecosystems," published Nov. 15, 2021 in the journal Plant Cell.
"A 'ziekzoeker' looks for diseased plants and I searched in particular for variegated white and red tulips--the ones you'd recognize from a golden-age Dutch still life painting," Groen related. "I learned how these tulips are infected with an aphid-transmitted virus and during my PhD in the group of John Carr at the University of Cambridge, I would further investigate the molecular mechanisms of how virus infections would change plant interactions with aphids and pollinators. I was gripped by the role that plant defensive chemicals play in shaping species interactions and I continued to study these as a postdoc with Noah Whiteman at the University of Arizona and the University of California, Berkeley.'
On the author page, he chronicled his previous work on the interactions between milkweeds and the monarch butterfly "and found out how the monarch evolved resistance to the cardenolide toxins that milkweeds make. While this work mostly revolved around a single gene of large effect, typically several or many genes are involved in organisms' evolutionary responses. As a Gordon and Betty Moore Foundation fellow in the group of Michael Purugganan at New York University, I learned about the latest developments in evolutionary genomics and systems biology while investigating patterns of natural selection on gene expression in rice populations that we grew under wet and dry field conditions with our collaborators at the International Rice Research Institute in The Philippines."
"The current paper (Plant Cell) is a culmination of this research," Groen related. "We found that under field drought rice plants do not just respond to changes in water availability, but also to concomitant changes in abundance of soil microbes that they interact with. As assistant professor in the Department of Nematology at the University of California, Riverside, I will continue to study rice and milkweed as well as plants from the nightshade family and look at the complex evolutionary tug-of-war between these plants and parasitic nematodes. Combining laboratory and field experiments, we will zoom in on the central role that plant chemicals play by using approaches from evolutionary and systems biology like the ones we describe in our paper."
Nematologist Shahid Siddique, assistant professor in the Department of Entomology and Nematology, coordinates the winter quarter seminars. He may be reached at ssiddique@ucdavis.edu for any technical issues involving the Zoom connection.
/span>- Author: Kathy Keatley Garvey
- Author: Kathy Keatley Garvey
That's the title of the next UC Davis Department of Entomology and Nematology seminar, to be presented Wednesday, Jan. 27 by assistant professor Charissa de Bekker of the University of Central Florida (UCF). The virtual seminar begins qt 4:10 p.m. Access this Google form link to join the seminar on Zoom.
"My lab studies parasites that change the behavior of their hosts," she writes on her website. "Nature harbors quite some bizarre examples of parasites that evolved the ability manipulate. These manipulations range from slightly altered existing behaviors to the establishment of completely novel ones that are not part of the host's regular repertoire."
"One of the most dramatic examples of the latter is that of the zombie ants. Here, a fungal parasite takes control of the behavior of a Carpenter ant, guiding it up the vegetation where it latches on in a final death grip. Working across various disciplines within the broad field of biology we use this parasite-host interaction as a model system to ask the question how a microbe can control an animal's brain to change the behavioral output so precisely. In addition, we know very little about how behavior in general is regulated. Our research will therefore not only inform us about the mechanisms that these parasites use to manipulate their hosts, but ultimately also give an important insight into the regulation of behavior in general."
De Bekker holds a five-year $970,000 National Science Foundation grant to study "parasitic fungi that hijack behaviors of their hosts."
A member of the UCF faculty since 2016, she received three degrees in biology from Utrecht University, The Netherlands: her bachelor's degree in 2004; her master's degree in 2006, and her doctorate in 2011. She specialized in molecular microbiology. She did postdoctoral research at the Center for Infectious Disease Dynamics, Department of Entomology, The Pennsylvania State University, from April 2011 to July 2012, and then served as a postdoctoral Marie Curie Fellow and Alexander von Humboldt Research Fellow at Ludwig-Maximilians University, Munich, Germany, before joining UCF. (See lab website)
Agricultural Extension specialist Ian Grettenberger of the UC Davis Department of Entomology and Nematology is coordinating the weekly seminars. He may be reached at imgrettenberger@ucdavis.edu
Media Coverage of Zombie Ant Research (Partial List):
- Five-Year Grant Will Deepen Research Into ‘Zombie Ants' (COS News, Feb. 26, 2020)
- The Science Behind Zombie Ants (UCF Today, Oct. 21, 2019)
- How a Parasitic Fungus Turns Ants Into 'Zombies' (National Geographic, April 18, 2019)
- The Science of Zombies: Will the Undead Rise? (Phys.Org, Nov. 1, 2019
Read National Public Radio's coverage of Zombie research (Oct. 31, 2019).
Further reading: How the Zombie Fungus Takes Over Ants' Bodies to Control Their Minds (The Atlantic, Nov. 14, 2017
See UC Davis Department of Entomology and Nematology website for list of other seminar speakers for the winter quarter
- Author: Kathy Keatley Garvey
The seminar takes place from 4:10 to 5 p.m., Wednesday, Oct. 28. Access this site for the Zoom link. Host is Cooperative Extension specialist and agricultural entomologist Ian Grettenberger, assistant professor, UC Davis Department of Entomology and Nematology. He is coordinating the department's fall seminars.
"The research in our lab focuses on understanding how chemical compounds mediate interactions among microbes, plants, herbivores, and herbivore natural enemies," Helms says. "We combine analytical chemistry and behavioral ecology in laboratory and field-based research to investigate how organisms use chemistry to navigate, communicate, and defend themselves. This seminar will discuss some of our ongoing projects examining how plants and insect herbivores use chemical information from their environment to assess their risk of attack and how herbivore natural enemies use such information to find potential prey."
Helms, an assistant professor, holds two degrees from Pepperdine University, Malibu, Calif., both awarded in 2009: a bachelor of science degree in biology and a bachelor of arts degree in biochemistry. She received her doctorate in ecology in 2015 from The Pennsylvania State University, State College, Penn. While in the John Tooker lab, Helms studied the chemical ecology of plant-insect interactions, especially how plants defend themselves against insect herbivores. She investigated how plants use olfactory cues to predict impeding herbivore attacks and the molecular mechanisms involved.
In addition to the general field of chemical ecology, Helms' research interests include plant-insect interactions, tritrophic interactions, belowground chemical ecology, chemical communication, and plant defense.
Her most recent publications:
Helms, A.M., Ray, S., Matulis, N.L.*, Kuzemchak, M.C.*, Grisales, W.*, Tooker, J.F., Ali, J.G. Chemical cues linked to risk: Cues from belowground natural enemies enhance plant defences and influence herbivore behaviour and performance. Functional Ecology. 33, 798-808 (2019). DOI: 10.1111/1365-2435.13297
Acevedo, F.E., Smith, P., Peiffer, M., Helms, A.M., Tooker, J.T., Felton, G.W. Phytohormones in fall armyworm saliva modulate defense responses in plants. Journal of Chemical Ecology. (2019). https://doi.org/10.1007/s10886-019-01079-z
Yip, E.C., Sowers, R.P.*, Helms, A.M., Mescher, M.C., De Moraes, C.M., Tooker, J.F. Tradeoffs between defenses against herbivores in goldenrod (Solidago altissima). Arthropod-Plant Interactions. 13, 279-287 (2019). DOI: 10.1007/s11829-019-09674-3
For any technical issues regarding the seminar, contact Grettenberger at imgrettenberger@ucdavis.edu.