- Author: Kathy Keatley Garvey
At least, the UC Davis headlines!
We're delighted to see that UC Davis undergraduate student Juan Amado “Ado” Sales, a member of the Research Scholars Program in Insect Biology and a laboratory assistant for nematologist Shahid Siddique, UC Davis Department of Entomology and Nematology, has just been awarded a coveted summer fellowship from the UC Davis Innovation Institute for Food and Health (ILFH) to do independent research on parasitic nematodes.
As we wrote in a news story today, Sales submitted his successful research application on “Toward a More Resistant Plant: Uncovering Plant Host Targets of Novel Plant Parasitic Nematode Effectors.” He is one of only four students to be awarded the summer fellowship.
Sales, who is on track to receive his bachelor's degree in biotechnology (with an emphasis on plant biotechnology) in June 2022, draws high praise from Siddique.
“Ado is a highly gifted student with a strong interest in agriculture and plant biology,” said Siddique. “I have really enjoyed one-on-one interaction with Ado and I have observed him growing academically and intellectually. He has a level of maturity in his research, including contributing ideas for troubleshooting, that I had no hesitations about giving him the space to continue his project independently. The IIFH fellowship program will add to his personal and professional growth and contribute to the experience of first-generation immigrant students like himself.”
ILFH awards Undergraduate Research Center Fellowships (URC-IIFH) to faculty-guided undergraduate students who perform research related to food, agriculture and health. Each fellow receives a summer research stipend, and funds for travel and/or research supplies. The fellows also will participate in professional development and entrepreneurship training, including the on-campus Entrepreneurship Academy. They will present their research results at the annual IIFH Innovator Summit in spring 2022, with opportunities to participate in the UC Davis Little Bang poster competition and the Big Bang competition.
His research involves RNA extraction, cDNA synthesis, Polymerase Chain Reaction (PCR), and gel electrophoresis, as well as GreenGate Cloning of plant parasitic nematodes genes. His skills also include seed germination and nematode hatching for plant-nematode assays, and the microscopic evaluation of nematode damage on plants.
Sales' journey to the Siddique lab began in May 2019 when he was selected a research scholar in the campuswide program, Research Scholar in Insect Biology (RSPIB), launched by UC Davis Entomology and Nematology faculty Jay Rosenheim, Joanna Chiu and Louie Yang to provide undergraduates with a closely-mentored research experience in biology. Students join in their first or second year and are placed in a faculty mentor's laboratory where they receive ongoing training and career guidance in research and scientific writing. They also learn how to present their research results at professional scientific meetings and to prepare applications for graduate or professional schools.
His research involves RNA extraction, cDNA synthesis, Polymerase Chain Reaction (PCR), and gel electrophoresis, as well as GreenGate Cloning of plant parasitic nematodes genes. His skills also include seed germination and nematode hatching for plant-nematode assays, and the microscopic evaluation of nematode damage on plants.
Sales' journey to the Siddique lab began in May 2019 when he was selected a research scholar in the campuswide program, Research Scholar in Insect Biology (RSPIB), launched by UC Davis Entomology and Nematology faculty Jay Rosenheim, Joanna Chiu and Louie Yang to provide undergraduates with a closely-mentored research experience in biology. Students join in their first or second year and are placed in a faculty mentor's laboratory where they receive ongoing training and career guidance in research and scientific writing. They also learn how to present their research results at professional scientific meetings and to prepare applications for graduate or professional schools.
Sales enrolled in Rosenheim's class, BIS2B (Introduction to Biology, Ecology and Evolution) and the rest is history, as they say.
It was in the Rosenheim class that Sales learned about RSPIB, joined the Siddique lab, and applied for--and received--the summer fellowship.
Well done, Ado Sales.
Next step? Explaining what the study of nematology (microscopic round worms) is all about? Read what Siddique says about plant parasitic nematodes.
- Author: Kathy Keatley Garvey
Molecular nematologist Peter DiGennaro of the University of Florida's Department of Entomology and Nematology will present his seminar on "Gaps in Molecular Plant Nematology" from 4:10 to 5 p.m. (Link to the form to join the Zoom meeting.)
"What has molecular plant nematology done for me?" asks DiGennaro, who will present a collection of short stories describing the need for, and benefits of, a symbiosis-centered approach in understanding plant-nematode interactions at the molecular level.
"Dr. DiGennaro does great work on plant-nematode interactions," said seminar host Shahid Siddique, assistant professor, UC Davis Department of Entomology and Nematology.
DiGennaro, interested in the molecular basis of nematode parasitism in plants, primarily researches the root-knot nematode (Meloidogyne spp.); specifically, he is concerned with nematode-derived signaling molecules and subsequent host responses. His lab utilizes an array of genomic, genetic and biochemical tools to understand the fundamental mechanisms behind nematode host range, parasitism, and plant responses.
"The goal of our research is to develop novel avenues for safe and sustainable nematode control strategies," he says.
DiGennaro received his bachelor of science degree in biochemstry in 2007 from the State University of New York at Geneseo, and his doctorate in functional genomics, with a minor in plant pathology, from North Carolina State University (NCSU) in 2013. At NCSU, he studied the molecular basis for nematode parasitism in plants. He served as a postdoctoral researcher with the Plant Nematode Genomics Group at both NCSU and at UC Berkeley before joining the University of Florida, Gainsville, in July 2016.
Coordinating the seminars is Cooperative Extension specialist Ian Grettenberger, assistant professor, UC Davis Department of Entomology and Nematology. For any technical issues, he can be contacted at imgrettenberger@ucdavis.edu.
Resources:
- See UC Statewide Integrated Pest Management Program's information on nematodes
- See how nematodes play hide and seek, news story on Shahid Siddique research
- Author: Kathy Keatley Garvey
You're not thinking of root-knot nematodes, major pests of potatoes.
But potato growers and nematologists are.
So are the editors of the scientific journal, Nature Plants. Their current edition showcases research on root-knot nematodes by Washington State University (WSU) scientists Lei Zhang and Cynthia Gleason, and a commentary by UC Davis nematologist Shahid Siddique and colleague Clarissa Hiltl of the University of Bonn, Germany.
“Plant-parasitic nematodes are among the world's most destructive plant pathogens, causing estimated annual losses of $8 billion to U.S. growers and of nearly $78 billion worldwide," according to Siddique, an assistant professor in the UC Davis Department of Entomology and Nematology.
“Most current control methods rely on chemical nematicides, but their use is increasingly limited due to environmental concerns," Siddique and Hiltl wrote in their News and Views column, New Allies to Fight Worms.
They commented that the WSU scientists' proposed alternative pest management strategy--naturally occurring molecules or plant elicitor peptides (Peps)—shows promise: “Engineering a naturally occurring rhizobacterium to deliver Peps to the plant root system offers a new opportunity in integrated pest management.”
It's better to build up the host plant's immune system rather than directly target the pathogen with chemical nematicides which “are highly toxic and have negative effects on the ecosystem," Siddique told us.
The root-knot nematode Meloidogyne chitwoodi is a noted pest of potato production in the Pacific Northwest. Idaho leads the nation in commercial potato production, followed by Washington. Oregon ranks fourth. California, which ranks eighth, grows potatoes year around due to its unique geography and climate.
The WSU scientists demonstrated the effective use of Peps to combat root-knot nematodes in potato (Solanum tuberosum). They engineered a bacteria, Bacillus subtillis, to secrete the plant-defense elicitor peptide StPep1. They wrote that pre-treatment of potato roots “substantially reduced root galling, indicating that a bacterial secretion of a plant elicitor is an effective strategy for plant protection." (See article.)
“Besides chemical nematicides, methods of nematode management include the use of crop rotation, microbial biocontrol agents, cover crops, trap crops, soil solarization, fumigation and resistant plant varieties,” wrote Siddique and Hiltl. “However, several of these strategies are not effective or available for all crops. Nematicides are highly toxic, and their use is strictly limited due to environmental concerns. Resistant plants are often ineffective or unavailable. Microbial biocontrol agents have produced inconsistent results. In this context, the current work provides a new opportunity to manage plant-parasitic nematodes by combining two progressive strategies: the use of plant elicitors to enhance crop resistance to pathogens and the use of B. subtilis to deliver.”
According to the UC Statewide Integrated Pest Management Program (UC IPM), root-knot nematodes "usually cause distinctive swellings, called galls, on the roots of affected plants. Infestations of these nematodes are fairly easy to recognize; dig up a few plants with symptoms, wash or gently tap the soil from the roots, and examine the roots for galls. The nematodes feed and develop within the galls, which can grow as large as 1 inch in diameter on some plants but usually are much smaller."
"Nematodes are too small to see without a microscope," UC IPM points out. "Often you become aware of a nematode problem by finding galled roots on a previous crop. However, you also can use a simple bioassay to detect root knot nematodes in garden soil. Melons seeded in pots in moist soil collected from the garden will develop visible galls on the roots in about 3 weeks when pots are kept at about 80ºF if root knot nematodes are present. As a comparison, melons planted in heat-sterilized soil won't develop galls."
Stay tuned.
- Author: Kathy Keatley Garvey
And UC Davis plant nematologist Shahid Siddique, formerly with the University of Bonn, is at the heart of it.
He led a 10-member international team in discovering the role of a plant's endodermal barrier system in defending against plant-parasitic nematodes.The Plant Journal published the research, Root Endodermal Barrier System Contributes to Defence against Plant‐Parasitic Cyst and Root-Knot Nematodes, in its July 19th edition.
Fast forward to October.
Research Highlight Editor Lysa Maron chose the work as the "research highlight" in her Oct. 14th article, “Breaking or Sneaking into the Fortress: the Root Endodermis is a Defence Wall Against Nematode Infection.” The journal also showcased the team's nematode image on the cover.
What's the significance of the research?
“We discovered that the integrity of the endodermis—a specialized cell layer that surrounds the vascular system and helps regulate the flow of water, ions and minerals--is important to restrict nematode infection,” said Siddique, an assistant professor in the UC Davis Department of Nematology who joined the faculty in March after serving several years at the University of Bonn.
“We found that having defects in endodermis make it easier for parasites to reach the vascular cylinder and establish their feeding site. Although, this finding is a result of basic research, it opens new avenues to for breeding resistance against cyst nematodes in crops.”
Maron noted that “Roots are a truly amazing plant structure: they conquer the underground, form complex structures that anchor the plant, let water and nutrients in, but must not dry out. Roots store energy, send signals to the aboveground parts of the plant and to neighbors, and defend the plant against soil-borne pathogens. Within the root, the endodermis is the barrier that separates the inner vasculature from the outer cortex. If the root is a fortress, the endodermis is the gated wall. Cell wall reinforcements such as the casparian strip (CS), lignin deposition, and suberin seal the apoplast of the endodermis throughout different parts of the root. These reinforcements allow the diffusion of water and nutrients to and from the vascular tissue while blocking its penetration by pathogens such as bacteria and fungi (Enstone et al., 2002).”
“But roots also face pathogens of a different kind: root-infecting, sedentary endoparasites such as cyst nematodes (CNs) and root-knot nematodes (RKNs),” Maron wrote. “These pathogens infect a variety of important crops and cause significant yield losses (Savary et al., 2019).”
Maron quoted Siddique: “According to Siddique, investigating root traits that affect plant-nematode interactions is important for finding new strategies for plant protection. Screening for natural variation in suberin- and lignin-related traits might help identify and develop stronger fortresses, i.e., plants with enhanced resilience against pathogens, drought, and nutrient deficiency.”
Siddique collaborated with scientists from Germany, Switzerland and Poland: Julia Holbein, Rochus Franke, Lukas Schreiber and Florian M. W. Grundler of the University of Bonn; Peter Marhavy, Satosha Fujita, and Niko Geldner of the University of Lasuanne, Switzerland; and Miroslawa Górecka and Miroslaw Sobeczak of the Warsaw University of Life Sciences, Poland.
“Plant-parasitic nematodes are among the most destructive plant pathogens, causing agricultural losses amounting to $80 billion annually in the United States,” said Siddique in an earlier news story. “They invade the roots of almond, tomato, beets, potato or soybeans and migrate through different tissues to reach the central part—the vascular cylinder--of the root where they induce permanent feeding sites.”
“These feeding sites are full of sugars and amino acids and provide the parasite all the nutrients they need,” Siddique explained. “A specialized cell layer called the endodermis surrounds the vascular system and helps regulates the flow of water, ions and minerals into and out of it. However, the role of endodermis in protecting the vascular system against invaders such as nematodes had remained unknown.
The German Research Foundation funded the research.
- Author: Kathy Keatley Garvey
And it has a University of California, Davis, connection.
An international team of 10 scientists, led by plant nematologist Shahid Siddique, a former research group leader at the University of Bonn, Germany, and now an assistant professor in the UC Davis Department of Entomology and Nematology, has discovered the role of a plant's endodermal barrier system in defending against plant-parasitic nematodes.
“We discovered that the integrity of the endodermis—a specialized cell layer that surrounds the vascular system and helps regulate the flow of water, ions and minerals--is important to restrict nematode infection,” said Siddique, who joined the UC Davis faculty in March after serving several years at the University of Bonn.
“We found that having defects in endodermis make it easier for parasites to reach the vascular cylinder and establish their feeding site. Although, this finding is a result of basic research, it opens new avenues to for breeding resistance against cyst nematodes in crops.”
The research, “Root Endodermal Barrier System Contributes to Defence against Plant‐Parasitic Cyst and Root‐Knot Nematodes,” is published in the July 19th edition of The Plant Journal.
Siddique collaborated with scientists from Germany, Switzerland and Poland: Julia Holbein, Rochus Franke, Lukas Schreiber and Florian M. W. Grundler of the University of Bonn; Peter Marhavy, Satosha Fujita, and Niko Geldner of the University of Lasuanne, Switzerland; and Miroslawa Górecka and Miroslaw Sobeczak of the Warsaw University of Life Sciences, Poland.
“Plant-parasitic nematodes are among the most destructive plant pathogens, causing agricultural losses amounting to $80 billion annually in the United States,” said Siddique. “They invade the roots of almond, tomato, beets, potato or soybeans and migrate through different tissues to reach the central part—the vascular cylinder--of the root where they induce permanent feeding sites.”
“These feeding sites are full of sugars and amino acids and provide the parasite all the nutrients they need,” Siddique explained. “A specialized cell layer called the endodermis surrounds the vascular system and helps regulates the flow of water, ions and minerals into and out of it. However, the role of endodermis in protecting the vascular system against invaders such as nematodes had remained unknown.”
In their abstract, the scientists noted that plant-parasitic nematodes (PPN) “cause tremendous yield losses worldwide in almost all economically important crops. The agriculturally most important PPNs belong to a small group of root‐infecting sedentary endoparasites that includes cyst and root‐knot nematodes. Both cyst and root‐knot nematodes induce specialized long‐term feeding structures in root vasculature from which they obtain their nutrients.”
“A specialized cell layer in roots called the endodermis, which has cell walls reinforced with suberin deposits and a lignin‐based Casparian strip (CS), protects the vascular cylinder against abiotic and biotic threats,” the researchers explained. “Until now, the role of the endodermis, and especially of suberin and the CS, during plant–nematode interactions was largely unknown.”
The research was funded by a grant from the German Research Foundation.
(Note: The Plant Journal is a peer-reviewed scientific journal of plant science published by Wiley-Blackwell for the Society for Experimental Biology. Established in 1991, the journal is published twice a month. Editor Lee Sweetlove says that the journal "provides a dynamic forum for the ever-growing international plant sciences research community and publishes in all key areas of plant biology.")
