May 30, 2023
Gaithersburg-based Silvec Biologics, a company developing RNA therapies for trees and plants, is expanding its platform by demonstrating compatibility with a variety of plants at the University of Maryland through the Maryland Industrial Partnerships (MIPS) program.
The company’s product can inoculate plants against viruses, fungi, and bacteria. It could also combat insects and enhance traits in host plants. What’s more, it could do so indefinitely, meaning no additional doses would be needed, and without genetic modification or harm to the environment.
“We introduce the therapy to a tree, and the tree itself then manufactures its own therapeutic agents and does so for the lifespan of the tree,” said Silvec CEO Rafael Simon.
Silvec’s initial target markets include perennial trees, vines, bushes and shoot plants. In an effort to explore additional markets, the company turned to MIPS and Anne Simon, Professor of Cell Biology & Molecular Genetics at the University of Maryland.
MIPS funds university research projects that team faculty with Maryland-based companies to develop technology products and processes. Both the company and MIPS provide funds for each project. All funds go to the university researchers.
During the first year of Silvec’s two-phase MIPS project, Anne’s lab tested the company’s platform on cacao, kiwi, banana, pear, papaya, coffee, watermelon, cucumber, and tomato plants. She found that it worked on four: watermelon, cucumbers, coffee, and tomatoes.
“This was a self-contained project that was well-suited for the university,” said Rafael. “Even though it did not work for many plants, it was something we needed to know. Even the negative results were really valuable to us. The fact we were able to do this offline and not distract our company team was important.”
Now, during the project’s second phase, Anne is working with a modified version of the platform that has already shown promise in coffee plants. “It’s 10-20 times better than the original product,” she said.
In addition, Anne is not only re-testing all plants from phase one with the new platform, she is also developing an assay to quickly determine new hosts for the product.
“As we understand more about how the product works, we believe we can find ways to make it compatible with a larger number of plants,” said Rafael.
Anne invented the core technology of Silvec’s platform, which the company licensed from UMD before incorporating in 2020. At the time, she was interested in combating invasive pathogens, which pose an increasing threat to plants with the global acceleration of travel, trade, and climate change.
One example is huanglongbing, a bacterial disease also known as Citrus Greening, which decimated citrus groves in Asia, Brazil, and the Dominican Republic before entering the U.S., where it has recently decreased Florida citrus fruit production by as much as 85 percent.
“Plants do not have the same types of weapons to fight pathogens, especially the ones they did not evolve with,” said Rafael. “They don’t have adaptive immune systems like mammals do. Plants don’t produce antibodies, and even if they did, they don’t have a circulatory system that can get them throughout the plant’s system.”
Anne discovered a novel, benign, virus-like, self-replicating RNA molecule, or replicon, that can move throughout a tree’s phloem, the pipeline through which sugars made in leaves are passed to the rest of the tree. She then inserted RNA fragments into the replicon that the plant converts into tiny, beneficial siRNAs, and found that the replicon moves throughout a tree’s phloem, copying itself and deploying the siRNAs. siRNAs can then attack invading viruses, or get transferred into pathogens like fungi and bacteria, where they silence critical genes so the pathogen no longer replicates, effectively killing it.
When a small tree branch containing the replicon is grafted onto another tree or rootstock, the vascular tissues fuse together, allowing the replicon to move into the phloem of the new tree where it exists permanently.
Silvec is pursuing regulatory approval for its product.
Rafael believes that RNA therapies represent the future for fighting pathogens in plants.
“Some day, we are going to look back with horror that we sprayed our food with so many chemicals that can be hazardous to people and the environment,” he said. “Conventional pesticides, fungicides, and biocides are in the process of being phased out. They kill a lot more than just weeds. They run off and do other damage and can be harmful to humans at various levels.”
Silvec has raised $7 million in funding from investors, interested end users, and through grants. The company has ten employees, four of whom are UMD graduates: Hannah Reuning ‘22, B.S. in Cell Biology & Molecular Genetics; Calvin Godfrey ‘20, B.S. in Neurobiology and Physiology; Jonathon Ladd ‘19, B.S. in Environmental Science; and Micki Kuhlmann ‘16, Ph.D. in Cell Biology & Molecular Genetics.
Jingyuan (Brianna) Liu, a postdoctoral researcher in Anne’s laboratory at UMD, works on the Silvec MIPS project. As a graduate student in her lab, she discovered that the replicons were mobile in plants, which was previously thought to be impossible.
Feng Gao, an assistant research scientist in the Simon Lab for 11 years, was the first Silvec employee.
The company has also developed a method for stabilizing its platform and is in the process of patenting many of its inventions.
