- Author: Kathy Keatley Garvey
It was the lab mates' first-ever conference, and they brought home first- and second-place awards, in addition to a second-place tie in the Cobb Bowl competition which memorializes Nathan Cobb (1859-1932), the father of nematology.
Alison Coomer Blundell, who will be a fourth-year doctoral candidate in Plant Pathology this fall, won first place in the three-minute student competition with her presentation on “Trade Offs Between Resistance Breaking and Fitness Cost in Root-Knot Nematodes.” She received a $250 award and a plaque.
Ching-Jung Lin, who will be a fourth-year doctoral student this fall, won second place in the 12-minute category with her presentation on "Elucidating the Role of MigPSY Peptides in Interactions Between Plants and Root-Knot Nematodes." She received a $250 prize.
The six-member Siddique lab team, "Meloidogyne Gang Gang," which included Blundell, Lin, third-year doctoral student Pallavi Shakya, and second-year doctoral student Veronica Casey, tied for second place in the Cobb Bowl, a jeopardy-like competition that can include both students and postdoctoral fellows on the teams.
"I am very humbled by the award and recognition but am very proud of seeing all my lab mates accomplish their presentations and get good feedback and recognition as well," said Blundell, who seeks a PhD in plant pathology. She holds two undergraduate degrees--a bachelor's degree in biology and a bachelor's degree in chemistry--from Concordia University, Seward, Neb.
“I was first introduced to nematodes in my undergraduate studies where I maintained C. elegans (Caenorhabditis elegans) cultures, but was introduced to plant parasitic nematodes when Dr. Siddique reached out to me about becoming a member in his lab," Blundell said. "This was my first time at SON, and for all my lab mates. SON has allowed me to meet people I have heard about or have talked to on Zoom, email, or twitter and also make new connections with many U.S. states and universities.”
Lin, a first-generation international student, credits co-principal investigator Professor Gitta Coaker of Plant Pathology and the Coaker Lab with mentoring her, offering presentation suggestions. "It was very much appreciated," she said.
- Question: "The Guava root-knot nematode."
Answer: "Meloidogyne enterolobii" - Question: "First report of root-knot nematodes."
Answer:"Who is Miles Joseph Berkeley?"
"The most difficult question, said team member Veronica Casey was: "The color of the first edition of the Journal of Nematology."
"The answer was simply, 'What is orange?' but many teams thought it was green," Casey related. "Another difficult question was 'The full species name of the Beech Leaf disease nematode.' The answer: "What is Litylenchus crenatae mccannii?"
The University of Idaho team won the Cobb Bowl. The UC Davis team, which also included a postdoctoral fellow from the University of Illinois and a graduate student from Montana State University, tied for second place with two other teams: AlohaNema, comprised primarily of students from the University of Hawaii, and Nemafolks, comprised of students from a number of universities, including Michigan State, Oregon State and Texas Tech. The other two teams represented the University of Florida and The Ohio State University.
Also at the SON meeting, Siddique participated in a session titled "Nematology Faces of the Future." In his five-minute self-introduction, he displayed a map showing how far he has traveled. A native of Multan, Pakistan, he received two degrees in Multan: his bachelor of science degree from the Government College Bosan Road in 2001 and his master's degree in botany from the Bahauddin Zakariya University in 2004. Then it was off to Vienna, Austria to receive his doctorate in 2009 in agriculture and biotechnology from the University of Natural Resources and Life Sciences. After serving as a research group leader for several years at the University of Bonn, Germany, he joined the UC Davis Department of Entomology and Nematology faculty in 2019 as an assistant professor and advanced to associate professor this year.
Alison Blundell Abstract
In her abstract, Blundell 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," she explained. "Utilizing the newly constructed reference genome for M. javanica (VW4), we compared genomes of VW4 and VW5 and identified an approximately 650 kb region that is present in VW4 but missing in VW5. This missing region contains ten 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." (Co-researchers and authors include P. Shakya, M. Winter, D. Lunt, V. M.Williamson, and S. Siddique)
Ching-Jung Lin Abstract
In her abstract, Lin wrote: "Plant parasitic nematodes pose a severe threat to global food production. These parasites invade plant roots and establish permanent feeding sites, which serve as their sole source of nutrients. To manipulate host responses, they secrete effectors such as phytohormones or peptides that hijack the host's cellular machinery. Plants produce a family of peptides called Plant Peptide Containing Sulfated Tyrosine (PSY) that promote root growth via cell expansion and proliferation. Intriguingly, the bacterial pathogen Xanthomonas oryzae pv. oryzae also produce a PSY-like peptide called RaxX (required for activation of XA21 mediated immunity X), which contributes to bacterial virulence. Our previous research has identified a group of secreted peptides called MigPSYs in root-knot nematodes (Meloidogyne spp.) that resemble plant PSY peptides and stimulate root growth in Arabidopsis. We found that MigPSY transcript levels are highest during the early stages of infection in rice and tomato plants. Furthermore, down-regulating expression of MigPSY results in reduced root galling and egg production, suggesting that the MigPSYs serve as nematode virulence factors. To gain a better understanding of the roles of MigPSYs, I plan to characterize the mechanisms underlying their function and host perception in plants. This research is expected to provide valuable insights into the mechanism of nematode infection and may lead to the development of new methods for controlling plant-parasitic nematodes." (Co-researchers and authors include H. Z. Yimer, D. D. Luu, A. C. Blundell, M. F. Ercoli, P, Vieira, V. M. Wlliamson, P. C. Ronald and S. Siddique)
The next SON meeting is Aug. 4-9, 2024, in Park City, Utah.