Tag Archives: Swadeshmukul Santra

Nano-treatment could help save mangroves from deadly disease

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Seems to be my week for coastal erosion. First, there was my August 23, 2024 posting “Electricity (electrodeposition) could help fight coastal (beach) erosion” and today, August 30, 2024, I’m featuring news I got about a month ago (late July 2024) regarding a special formula to help save mangroves on the Florida coast and other coasts where they are found.

A July 26, 2024 news item on ScienceDaily features news from the University of Central Florida, Note: Links have been removed,

Mangroves and palm trees are hallmarks of the Sunshine State not just for their beauty but for their immense importance to Florida’s coastlines.

Mangroves are crucial because they naturally protect coastal shores from storm damage and serve as vital wildlife habitats around the world.

Scientists at the University of Central Florida are working to preserve mangroves in Florida and across the world from an increasingly prevalent disease-causing variety of fungi that lies dormant but becomes active when the tree is exposed to stressors such as temperature fluctuation, pests or other diseases.

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A July 26, 2024 University of Central Florida (UCF) news release by Eddy Duryea (also on EurekAlert), which originated the news item, describes the disease (which hasn’t yet been formally named) and gives some details about the proposed treatment, Note: Links have been removed,

The disease does not yet have an official name, but it is being referred to by scientists as “Mangrove CNP.” It is caused by a group of fungal pathogens, including Curvularia, Neopestalotiopsis, and Pestalotiopsis, that causes yellowing and spots, and gradually weaken the mangrove until it ultimately dies.

Melissa Deinys, a UCF undergraduate researcher, and Jorge Pereira, a UCF graduate research assistant, are working to help turn the tide by developing and testing a promising nutritional cocktail comprised of nanoparticles to strengthen mangroves and counter the pathogens. The work is through UCF professor Swadeshmukul Santra’s Materials Innovation for Sustainable Agriculture (MISA) center at UCF, which is a U.S. Department of Agriculture-National Institute of Food and Agricultural recognized Center of Excellence.

Mangrove CNP in Florida was first identified as causing mangrove die-offs by Deinys in 2019 in Miami through her work with Fairchild Tropical Botanic Garden. Later, the Marine Resources Council, a non-profit organization dedicated to the protection and restoration of Florida’s Indian River Lagoon, verified and cited her efforts.

Deinys and collaborators with the MRC and Fairchild Tropical Botanic Garden have determined that about 80% of the mangroves they had sampled have tested positive for at least one of the fungal pathogen species. She says they have sampled over 130 mangroves between the Indian River Lagoon and Miami mangrove populations.

The researchers are treating the mangroves by soaking them in a nutrient solution called “Mag Sun” (MgSuN), which is comprised of magnesium and sulfur nanoparticles. The mixture is a refinement of a previous graduate student’s formula that destroyed bacteria on tomatoes, Pereira says.

“The reason why we choose magnesium is because it is more environmentally friendly, and plants need a lot of magnesium,” he says. “I combined our magnesium formulation with a sodium polysulfide. Sulfur is one of those elements that is ubiquitous in the environment, and the idea is that you can combine both to actually enhance the anti-microbial capacity for both bacteria and fungi and you also supply key nutrients to the plants so that they can grow greener and leafier.”

During lab tests, the researchers say they observed growth inhibition of up to 95% when treated with MgSuN at varying concentrations compared to the untreated control.

The formula acts as a sort of antibiotic and multivitamin, and it has shown great potential in bolstering the health of infected mangroves at nurseries across Florida, Pereira says.

“We’ve done some experiments, and we have tested both in vitro and in plants,” he says. “We’re working with the nurseries, and we’ve seen it does kill the pathogens with no detrimental effects to the mangroves while kickstarting their health. They look great after treatment.”

Deinys is continuing her work with the Fairchild Tropical Botanic Garden, MRC and nurseries across Florida while staying the course on her path to graduation and furthering her research at UCF.

She began studying the fungal pathogens in 2018 in Miami prior to being enrolled at UCF and has seen the mangroves become increasingly affected by the pathogens’ opportunistic nature.

“Back at the botanical gardens where I started, I would see the plants have these pathogens but not to a detrimental effect where we now see these organisms collapsing,” she says. “A mangrove nursery [The Marine Resources Council] had reached out to us, and they told us they had an insect infestation and then the whole population got wiped out by the pathogen. We’re also getting reports from places like Tampa that say areas that have more runoff are having more pathogen-related deterioration compared to 10 years ago.”

The fungi have been well-documented for some time, but volatile temperature changes, frequent storms and other increasing stressors open the door to the fungi taking a hold of the mangroves, Deinys says.

“They’re called opportunistic, and they’re called that for a reason,” she says. “They see a change in the plant and that’s when they start to take effect.”

How the pathogens are acquired is something that remains unclear, Deinys says. Researchers hypothesize it may be introduced through water, wind or insects, but further studies are needed to determine how it is acquired since it poses threat to mangrove health.

“You have to study all possibilities to determine what is the vector,” Deinys says. “We’ve seen papers and literature in other countries that have shown these pathogens for a long time. It’s been difficult because there is a disconnect in mangrove communities because we’re worlds apart and with different languages.”

The MgSuN nutrient solution is a treatment, but not a cure, Deinys says. There still are ample stressors that should be managed and mitigated, such as human-caused habitat destruction, in addition to treating the pathogens.

“I think there’s a big restoration effort to repopulate mangroves,” she says. “But first we need to look at the health of these mangroves and the health of the ecosystem before we determine what more we should do. We’re working with mangrove nurseries to see if we can together develop solutions.”

Maintaining and restoring mangroves is an essential component of ecological stewardship, and it’s a passion that Deinys hopes to continue throughout her career.

“I started this project my freshman year,” she says. “I didn’t want to leave what I was doing, and I came here with a mission. I met with Dr. Santra, our PI, and he wanted to help. He gave me a lot of freedom, and I’m really grateful.”

Deinys says that her research at UCF has been incredibly gratifying.

“There is a sense of community here that I found,” she says. “I joined the lab, and it felt like I found my family and that’s one of the best things to have come out of this experience. This has been one of my life’s passions, and I hope I’ll always stay with this project even after.”

Santra is encouraged by the research conducted by Pereira and Deinys, and he is hopeful it continues to bolster mangrove ecosystems.

“The UCF MISA center is dedicated to solving global problems that threaten agricultural sustainability,” he says. “We are excited to have another crop protection tool in our toolbox for protecting mangroves. I see the future of MagSun as a broad-spectrum fungicide, where GRAS (Generally Recognized As Safe) materials are empowered through nanotechnology.”

Further studies are needed to pinpoint which stressors are affecting the mangroves the most so that scientists can better preserve them, Pereira says.

“It’s very important to understand the stressors, and we need to really address if it’s a change in temperature, if it’s runoff or if it’s an additional pathogen,” he says. “In the meantime, we need to do something to prevent this damage from occurring.”

Researchers’ Credentials

Deinys graduated from BioTECH @ Richmond Heights High School, a conservation biology magnet school, where she began her research journey at Fairchild Tropical Botanic Garden and specialized in botany. In Fall 2022, Deinys joined UCF and became a member of the Santra Lab the following spring. She is an undergraduate research assistant working towards her bachelor’s degree in biotechnology.

Pereira graduated from Universidad Nacional Autónoma de Honduras with a degree in industrial chemistry. He joined Santra’s lab in 2020 and is currently a graduate research assistant and working toward his doctoral degree in chemistry.

Santra holds a doctorate in chemistry from the Indian Institute of Technology Kanpur. After graduating, he worked at the University of Florida (UF) as a postdoctoral researcher and later as a research assistant professor at the UF Department of Neurological Surgery and Particle Engineering Research Center. In 2005, Santra joined UCF as an assistant professor at the NanoScience Technology Center, the Department of Chemistry and the Burnett School of Biomedical Sciences. He is the director of the UCF Materials Innovation for Sustainable Agriculture center, a USDA-NIFA-recognized Center of Excellence.

They don’t seem to have published a paper about their work but there is this video,

Effective treatment for citrus-destroying disease?

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Citrus greening is a worldwide problem. A particularly virulent disease that destroys citrus fruit, it’s a problem that is worsening. Before getting to the research from the University of California at Riverside (UCR), here’s more about the disease and how it’s developing from the UCR Huanglongbing, (HLB, Citrus Greening webpage,

The Situation: Citrus huanglongbing (HLB), previously called citrus greening disease, is one of the most destructive diseases of citrus worldwide.  Originally thought to be caused by a virus, it is now known to be caused by unculturable phloem-limited bacteria.  There are three forms of greening that have been described.  The African form produces symptoms only under cool conditions and is transmitted by the African citrus psyllid Trioza erytreae, while the Asian form prefers warmer conditions and is transmitted by the Asian citrus psyllid Diaphorina citri.  Recently a third American form transmitted by the Asian citrus psyllid was discovered in Brazil.  This American form of the disease apparently originated in China.  In North America, the psyllid vector, Diaphorina citri, of HLB is found in Florida, Louisiana, Georgia, South Carolina, Texas and Hawaii, and recently arrived in Southern California from Mexico. HLB is known to occur in Florida Lousiana, South Carolina, Georgia, Cuba, Belize and the Eastern Yucatan of Mexico.  A federal quarantine restricts all movement of citrus and other plants in the family Rutaceae from Asian Citrus Psyllid or HLB-infested areas into California in order to prevent introduction of the disease.

 Damage:  The HLB bacteria can infect most citrus cultivars, species and hybrids and even some citrus relatives.  Leaves of newly infected trees develop a blotchy mottle appearance.  On chronically infected trees, the leaves are small and exhibit asymmetrical blotchy mottling (in contrast to Zinc deficiency that causes symmetrical blotching).  Fruit from HLB-infected trees are small, lopsided, poorly colored, and contain aborted seeds. The juice from affected fruit is low in soluble solids, high in acids and abnormally bitter.  The fruit retains its green color at the navel end when mature, which is the reason for the common name “citrus greening disease.”  This fruit is of no value because of poor size and quality.  There is no cure for the disease and rapid tree removal is critical for prevention of spread.

Economic Impact: HLB is one of the most devastating diseases of citrus and since its discovery in Florida in 2005, citrus acreage in that state has declined significantly.  If the disease were to establish in California, the nursery industry would be required to move all of their production under screenhouses, pesticide treatments for the vector would be instituted resulting in greatly increased pesticide costs (3-6 treatments per year) and indirect costs due to pesticide-induced disruption of integrated pest management programs for other citrus pests.  A costly eradication program would need to be instituted to remove infected trees in order to protect the citrus industry.

Distribution of HLB: In April 2012, after about a week of testing, the California Department of Food and Agriculture (CDFA) removed a pumelo tree with a lemon graft from Hacienda Heights in Los Angeles County after the tree and an Asian citrus psyllid found on the tree both tested positive for Huanglongbing. In 2005, HLB was also found in Florida and it is now known to occur in Louisiana, Georgia, South Carolina, Cuba, Belze and Eastern Mexico.  Worldwide, HLB is also present in China, eastern and southern Africa, the Indian subcontinent, Mauritius, Reunion, the Saudi Arabian peninsula, and southeast Asia.

Research:  Research is focusing on characterization of the bacteria, development of detection methods, and control of the disease and the psyllid.  To date, control of the disease is based on planting HLB-free citrus germplasm, eradication of infected citrus plants, and control of the vector with systemic insecticides.  Countries with HLB learn to manage the disease so that they can still produce citrus.  In California, the best strategy is to keep this disease out. This goal is supported by both federal and state quarantine regulations and the University of California’s Citrus Clonal Protection Program, which provides a mechanism for the safe introduction of citrus germplasm into California.

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A July 7, 2020 news item on phys.org announces what researchers hope can be used commercially as a new treatment for citrus greening disease from researchers University of California at Riverside (UCR), Note: Links have been removed,

UC Riverside scientists have found the first substance capable of controlling Citrus Greening Disease, which has devastated citrus farms in Florida and also threatens California.

The new treatment effectively kills the bacterium causing the disease with a naturally occurring molecule found in wild citrus relatives. This molecule, an antimicrobial peptide, offers numerous advantages over the antibiotics currently used to treat the disease.

UCR geneticist Hailing Jin, who discovered the cure after a five-year search, explained that unlike antibiotic sprays, the peptide is stable even when used outdoors in high heat, easy to manufacture, and safe for humans.

A July 7, 2020 UCR news release (also on EurekAlert) by Jules Bernstein, which originated the news item, provides technical detail and information about plans to commercialize the product,

“This peptide is found in the fruit of Australian finger limes, which can naturally tolerate Citrus Greening bacteria and has been consumed for hundreds of years,” Jin said. “It is much safer to use this natural plant product on agricultural crops than other synthetic chemicals.”

Currently, some growers in Florida are spraying antibiotics and pesticides in an attempt to save trees from the CLas bacterium that causes citrus greening, also known as Huanglongbing or HLB.

“Most antibiotics are temperature sensitive, so their effects are largely reduced when applied in the hot weather,” Jin said. “By contrast, this peptide is stable even when used in 130-degree heat.”

Jin found the peptide by examining plants such as the Australian finger lime known to possess natural tolerance for the bacteria that causes Citrus Greening Disease, and she isolated the genes that contribute to this innate immunity. One of these genes produces the peptide, which she then tested over the course of two years. Improvement was soon visible.

“You can see the bacteria drastically reduced, and the leaves appear healthy again only a few months after treatment,” Jin said.

Because the peptide only needs to be reapplied a few times per year, it is highly cost effective for growers. This peptide can also be developed into a vaccine to protect young healthy plants from infection, as it is able to induce the plant’s innate immunity to the bacteria.

Jin’s peptide can be applied by injection or foliage spray, and it moves systemically through plants and remains stable, which makes the effect of the treatment stronger.

The treatment will be further enhanced with proprietary injection technology made by Invaio Sciences. UC Riverside has entered into an exclusive, worldwide license agreement with Invaio, ensuring this new treatment goes exactly where it’s needed in plants.

“Invaio is enthusiastic to partner with UC Riverside and advance this innovative technology for combating the disease known as Citrus Greening or Huanglongbing,” said Invaio Chief Science Officer Gerardo Ramos. “The prospect of addressing this previously incurable and devastating crop disease, helping agricultural communities and improving the environmental impact of production is exciting and rewarding,” he said. “This is crop protection in harmony with nature.”

The need for an HLB cure is a global problem, but hits especially close to home as California produces 80 percent of all the fresh citrus in the United States, said Brian Suh, director of technology commercialization in UCR’s Office of Technology Partnerships, which helps bring university technology to market for the benefit of society through licenses, partnerships, and startup companies.

“This license to Invaio opens up the opportunity for a product to get to market faster,” Suh said. “Cutting edge research from UCR, like the peptide identified by Dr. Jin, has a tremendous amount of commercial potential and can transform the trajectory of real-world problems with these innovative solutions.”

You can find out more about Invaio Sciences here.

Citrus greening has been featured here before in an April 7, 2015 posting titled, Citrus canker, Florida, and Zinkicide. There doesn’t seem to have been much progress made with this Florida solution for citrus greening. This 2018 document on nano.gov was the most recent I could find, ZinkicideTM- a systemic nano-ZnO based bactericide/fungicide for crop protection by Swadeshmukul Santra.

Citrus canker, Florida, and Zinkicide

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Found in Florida orchards in 2005, a citrus canker, citrus greening, poses a serious threat to the US state’s fruit industry. An April 2, 2105 news item on phys.org describes a possible solution to the problem,

Since it was discovered in South Florida in 2005, the plague of citrus greening has spread to nearly every grove in the state, stoking fears among growers that the $10.7 billion-a-year industry may someday disappear.

Now the U.S. Department of Agriculture has awarded the University of Florida a $4.6 million grant aimed at testing a potential new weapon in the fight against citrus greening: Zinkicide, a bactericide invented by a nanoparticle researcher at the University of Central Florida.

An April 2, 2015 University of Central Florida news release by Mark Schlueb (also on EurekAlert), which originated the news item, describes the problem and the solution (Zinkicide),

Citrus greening – also known by its Chinese name, Huanglongbing, or HLB – causes orange, grapefruit and other citrus trees to produce small, bitter fruit that drop prematurely and is unsuitable for sale or juice. Eventually, infected trees die. Florida has lost tens of thousands of acres to the disease.

“It’s a hundred-year-old disease, but to date there is no cure. It’s a killer, a true killer for the citrus industry,” said Swadeshmukul Santra, associate professor in the NanoScience Technology Center at UCF.

The bacteria that causes HLB is carried by the Asian citrus psyllid, a tiny insect that  feeds on leaves and stems of infected citrus trees, then carries the bacteria to healthy trees.

Zinkicide, developed by Santra, is designed to kill the bacteria.

The $4.6 million grant is the largest of five totaling $23 million that were recently announced by the USDA’s National Institute of Food and Agriculture.

The evaluation of Zinkicide is a multi-institute project involving 13 investigators from six institutions. Evan Johnson of UF’s [University of Florida] Citrus Research and Education Center at Lake Alfred is the project director, and there are a dozen co-principal investigators from UF, UCF, Oak Ridge National Laboratory (ORNL), Auburn University, New Mexico State University and The Ohio State University.

”Managing systemic diseases like HLB is a difficult challenge that has faced plant pathologists for many years,” said Johnson “It is a privilege to work with an excellent team of researchers from many different disciplines with the goal of developing new tools that are both effective and safe.”

A portion of the grant money, $1.4 million, flows to UCF, where Santra leads a team that also includes Andre Gesquiere, Laurene Tetard and the Oak Ridge National Laboratory collaborator, Loukas Petridis.

HLB control is difficult because current bactericidal sprays, such as copper, simply leave a protective film on the outside of a plant. The insect-transmitted bacteria bypasses that barrier and lives inside a tree’s fruit, stems and roots, in the vascular tissue known as the phloem. There, it deprives the tree of carbohydrate and nutrients, causing root loss and ultimately death. For a bactericide to be effective against HLB, it must be able to move within the plant, too.

Zinkicide is a nanoparticle smaller than a single microscopic cell, and researchers are cautiously optimistic it will be able to move systemically from cell to cell to kill the bacteria that cause HLB.

“The bacteria hide inside the plant in the phloem region,” Santra said. “If you spray and your compound doesn’t travel to the phloem region, then you cannot treat HLB.”

Zinkicide is derived from ingredients which are found in plants, and is designed to break down and be metabolized after its job is done. [emphasis mine]

It’s the first step in a years-long process to bring a treatment to market. UF will lead five years of greenhouse and field trials on grapefruit and sweet orange to determine the effectiveness of Zinkicide and the best method and timing of application.

The project also includes research to study where the nanoparticles travel within the plant, understand how they interact with plant tissue and how long they remain before breaking down. [emphasis mine]

If effective, the bactericide could have a substantial role in combatting HLB in Florida, and in other citrus-producing states and countries. It would also likely be useful for control of other bacterial pathogens infecting other crops.

The Zinkicide project builds as a spinoff from previous collaborations between Santra and UF’s Jim Graham, at the Citrus Research and Education Center to develop alternatives to copper for citrus canker control.

The previous Citrus Research and Education Foundation (CRDF)-funded Zinkicide project has issued three reports, for June 30, 2014, Sept. 30, 2014, and Dec. 31, 2014. This project’s completion date is May 2015. The reports which are remarkably succinct, consisting of two paragraphs, can be found here.

Oddly, the UCF news release doesn’t mention that Zinkicide (although it can be inferred) is a zinc particulate (I’m guessing they mean zinc nanoparticle) as noted on the CRDF project webpage. Happily, they are researching what happens after the bactericide has done its work on the infection. It’s good to see a life cycle approach to this research.