Assistant Professor, Dr. Zalamea. (Photo courtesy of Dr. Zalamea)
Assistant professor in the USF College of Arts and Sciences, Department of Integrative Biology, Dr. Paul-Camilo Zalamea is preparing a four-year research study on plant-soil microbial interactions, after receiving a $1.5 million grant through the National Science Foundation (NSF).
Growing up in Bogotá, Colombia, Zalamea was surrounded by a diverse ecosystem. But it wasn’t until he was an undergraduate student studying biology at the Universidad de Los Andes, that his desire to pursue tropical ecology came to a head. He had the opportunity to study in the Amazon basin, which changed his perspective and ultimately became the reason for his research today.
“When I was an undergrad, I had the great opportunity to go and live in the Amazon, basically in the middle of the Amazon basin between Colombia, Brazil, and Peru for months. I did an internship there for six months and that transformed my way of looking at the forest. I decided, well, I want to be a tropical plant community ecologist,” he said.
After earning a PhD and completing two post-doctoral positions at the Smithsonian Tropical Research Institute, Zalamea began his position as an assistant professor at USF. When he’s not molding the minds of tomorrow's researchers, he uses his downtime to continue his tropical ecology research.
This year was monumental for Zalamea as the NSF awarded a collaborative grant of $1,523,069 to four universities interested in studying the interactions between seeds and fungi. The four institutions that were awarded the grant include, the University of Illinois Urbana-Champaign, Utah State University, the University of Arizona, and the University of South Florida. Zalamea is the main principal investigator (PI) for the research proposal and secured $788,505 of the funding on behalf of USF, to support the research program.
With Zalamea being the main PI for this four-year grant, he has decided to set up a base camp for the research at the Smithsonian Tropical Research Institute’s facilities on Barro Colorado Island and Gamboa laboratories in Panama.
View of the Panama Canal. (Photo courtesy of Carolina Sarmiento, USF)
Barro Colorado Island sits in the middle of the Panama Canal and is one of the most studied tropical forests in the world. Joining him on the island and in Gamboa are a team of USF faculty and students: USF research associate and PI Carolina Sarmiento, post-doctoral fellow Lindsay McCulloch, and PhD student Gabriela Quesada.
Zalamea has dedicated the majority of his career to studying tropical ecology. Now, with the support of this large collaborative grant, this research project aims to unravel the mysteries surrounding the maintenance of tropical tree species diversity and how they manage to thrive in such unique environments.
The first objective of this research project is to understand how seed chemistry influences interactions with enemies. Specifically, what types of challenges do those seeds face?
Zalamea says that for larger seeds, the main enemies are granivores such as rodents, but smaller seeds are subject to attack by fungal pathogens.
He explains that a fungal pathogen is a type of fungi that behaves like a bad guest at a party. While most fungi are harmless, fungal pathogens attack the plant host. These fungal pathogens are especially important to study, as understanding their interaction is key to determining the survivability of these seeds. While fungal pathogens can cause harm, it's important to note that certain fungi can benefit certain seeds.
"We all want to drink kombucha, probiotics, or fermented drinks," he said.
"Well, because we know that microorganisms present in yogurt or kombucha are key for maintaining a healthy balance of the gut microbiome. In seeds, we know that fungi can also play positive roles in keeping seeds alive and ready before germination. One of the things we are doing is characterizing the chemistry of those seeds and looking at how those chemistries can explain the susceptibility of those seeds to being infected either by pathogenic fungi or beneficial fungi."
The second objective of this research is to investigate how interactions between microorganisms and seeds vary based on geographical locations or maternal sources of seeds.
Dr. Zalamea recovering buried seeds. (Photo courtesy of Rodrigo Arangua, AFP)
Panama is the ideal spot for studying these interactions under different geographical landscapes, as the Panama Canal provides access to both the Pacific Ocean and the Caribbean in one 50-mile stretch.
Zalamea says this is especially helpful for his team as their research includes seed burial experiments to see what fungal communities take the seeds in dry versus wet environments of Pacific versus Caribbean forests.
The last objective of this research is to study priority effects.
"In ecology, we have something that is called priority effects. In the case of microbes, what that means is that the order of colonization by microorganisms determines the fate of the organism that is colonized.
Let's imagine one seed is colonized first by a beneficial fungus, but then after that colonization, that same seed can be colonized by a pathogen," Zalamea explains. "If that happens, there is a likelihood that the seed will not die of this colonization by a pathogen because it is somehow defended by the beneficial fungus that colonized initially. If infection happens the other way around, if first the seed gets colonized by the pathogen, what happens is that that particular seed will die. So, the colonization order will determine the outcome of those colonizations."
Zalamea and his team have discovered that seed microbiomes are not very diverse. They have observed that typically only one or a few species of fungi colonize the seed at any given time. In experiments, the team inoculates various types of fungi into the seeds to determine how the order of colonization affects the seed's ability to germinate and develop.
Zalamea finds that his research holds significant importance and hope for the future since its findings can be applied to other ecosystems, benefiting agriculture by understanding and protecting seeds from microbial attacks.
“Even if we are not directly working with crops, some of the findings that I hope to get with this team of researchers in the next couple of years will be applicable for agricultural purposes,” he said.
Additionally, the research addresses the role of seeds in the carbon cycle.
"Pieces of evidence showing that forests play a key role in capturing carbon via photosynthesis," Zalamea explained. "Concerns we have in the scientific community is that forests at some point can break and become carbon sources which would be catastrophic regarding climate change or regulating the climate."
"So, knowing which species will be the species that will do well in the future will help us to understand if forests continue with this key role they have of capturing CO2," he said.
The project also profoundly impacts students and future researchers, according to Zalamea.
Mascagnia nervosa seed germinating. (Photo courtesy of Gabriela Quesada-Avila, USF)
Seed experiments in a lab. (Photo courtesy of Linda Wu, Penn State)
Through the collaborative grant, students from four universities, including USF, will participate in the research on Barro Colorado Island and beyond. They will learn from experts in various fields and contribute to the research. Interacting with diverse scientists, including tropical ecologists, botanists, mycologists, and more, will open doors for new perspectives, enriching the students' growth and future contributions to the scientific community.
“Having the possibilities to interact with people doing research on completely different topics is really a fantastic opportunity, especially for young scientists or students starting their careers,” Zalamea said.
“I'm a believer that different points of view will help us understand natural phenomena better. So, having people with different points of view based in the same space will help us achieve those things.”
Learn more about the Zalamea Lab.