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Deep ultraviolet fluorescence sensing with multispectral imaging to detect and monitor food‐borne pathogens on the leafy green phyllosphere

Spo0A-dependent antifungal activity of a plant growth promoting rhizobacteria Bacillus subtilis strain UD1022 against the dollar spot pathogen (Clarireedia jacksonii)

The Use of Synthetic Microbial Communities (SynComs) to Improve Plant Health

Surfactin and Spo0A-Dependent Antagonism by Bacillus subtilis Strain UD1022 against Medicago sativa Phytopathogens

Protocol: a simple method for biosensor visualization of bacterial quorum sensing and quorum quenching interaction on Medicago roots

Harsh Bais is a Plant Biotechnologist at the University of Delaware who focuses on understanding the biological significance of root exudation. His research pursues a multidisciplinary approach by interfacing plant biology and chemistry to unravel the underground communication process.

Plant-Microbe Interactions

Plant Biology

Plant Signaling

Root Exudation

Plant and Soil Sciences and Horticulture

Environmental Genomics

Critical Zone Research

University of Delaware Expert Profile

Humanity in Deep Space

Google Scholar Citations

ResearchGate Citations

Speeding up pathogenic bacteria testing

Test before you taste | UDaily

Double-edged sword | UDaily

Newsday

Oh No, Salmonella Has Found a Way to Avoid Being Washed Off Our Salads

UD researchers explore ways to prevent future salmonella outbreaks

COMPOSITIONS AND METHODS FOR INCREASING BIOMASS, IRON CONCENTRATION, AND TOLERANCE TO PATHOGENS IN PLANTS

INCREASING WATER RETENTION IN SOIL TO MITIGATE DROUGHT

new-path-to-combating-global-malnutrition-found-in-soil

Professor, Plant and Soil Sciences

 A new University of Delaware study has found that a naturally occurring soil microbe can boost protein-building amino acids in wheat. The finding by UD's Harsh Bais and others could pave the way for nutrient-rich staple crops — helping combat global malnutrition as fluctuations in weather reduce crop quality.

In the study, published in the journal Frontiers in Microbiology, Bais and a team of researchers from UD, Stroud Water Research Center and the Rodale Institute investigated how a bacteria naturally found in the soil that is beneficial to human health can enhance the levels of the amino acid and antioxidant ergothioneine in spring wheat. 

The researchers grew the spring wheat — one of the most widely consumed cereal crops — in a laboratory. After letting the seeds germinate and grow for seven days, they added a strain of bacteria called Streptomyces coelicolor M145 to the spring wheat roots. After combining the bacteria and the plant, they separated the plant’s leaves and roots. Then, they extracted the amino acid ergothioneine from the samples, working to determine how much protein was in the plant’s roots and shoots. 

They found that 10 days after S. coelicolor had been added to the spring wheat roots, the bacteria was able to inhabit spring wheat’s roots and shoots, producing ergothioneine, bypassing the plant’s innate defense mechanisms, and fortifying the spring wheat.

Wheat roots were inoculated with the benign bacteria Streptomyces coelicolor. The image shows the presence of bacteria on the root hairs on day 5.  “It’s unusual," Bais said. “Unless there is a mutual advantage for either the plant or the microbe.” 

The findings suggest that an alternative plant breeding approach could be utilized to associate plants with benign microbes to increase protein content in staple crops. All of our cereal crops are very low in protein. Think rice and breakfast cereals, common foods people eat, derived from these crops.

“This approach of harnessing a natural association of microbes with plants may facilitate fortifying our staple crops, enhancing global nutritional security,” Bais said.

Bais said he believes using microbes to transport nutrients depends on the microbes’ relationship with plants’ roots. He continues to work to catalyze the colonization of plant roots by beneficial microbes.

"Establishing a partnership with the appropriate types of microbes or microbial consortia for plants represents a method of engineering the rhizosphere — the region of the soil near plant roots — to foster a more favorable environment for either microbial associations that stimulate plant growth traits or enhance nutrient availability, which is the path forward,” Bais said.

Bais, a professor of plant biology who was named a UD Innovation Ambassador earlier this year, said plants’ “below-ground” traits, such as how nutrient-dense they are, have long been overlooked.

“As far as food security, we will have significant challenges by 2050 when the world’s population doubles,” Bais said. “We incentivize our farmers for crop yield; we don’t incentivize them for growing nutrient-dense crops. Growing nutrient-dense plants will enable the population to be fed better and avoid any potential nutrient deficiencies.”

The study was funded by the U.S. Department of Agriculture and the Foundation for Food and Agriculture Research.

Scientists have become more interested in soil bacteria as a means to solve issues with malnutrition and nutrient deficiencies. Alex Pipinos, the lead author and a UD Class of 2025 graduate with a master’s in microbiology, said environmental conditions are one factor diminishing protein content in plants.

“Essentially, crops are becoming less nutrient-dense,” Pipinos said. “The more nutrients in crops, the more healthy humans can be.” 

Pipinos points to a strong link between soil microbes, plant health and human health. Ergothioneine, she said, has already been shown to lower the risk of cardiovascular disease. It’s also been shown to combat cognitive decline, with a strong link to healthy cognitive aging. 

“By enhancing ergothioneine in plants, we can improve human health,” Pipinos said.

To reach Bais directly and arrange an interview, visit his profile and click on the contact button. Reporters can also contact UD's Media Relations Department. 

New path to combating global malnutrition found in soil

research-add-space-salad-to-the-risks-astronauts-face

Professor, Microbial Food Safety

 University of Delaware researchers grew lettuce under conditions that imitated the weightless environment aboard the International Space Station and found those plants were actually more prone to infections from Salmonella. 

It’s been more than three years since the National Aeronautics and Space Administration made space-grown lettuce an item on the menu for astronauts aboard the International Space Station. Alongside their space diet staples of flour tortillas and powdered coffee, astronauts can munch on a salad, grown from control chambers aboard the ISS that account for the ideal temperature, amount of water and light that plants need to mature.

But as the UD researchers discovered, there is a problem. The International Space Station has a lot of pathogenic bacteria and fungi. Many of these disease-causing microbes at the ISS are very aggressive and can easily colonize the tissue of lettuce and other plants. Once people eat lettuce that’s been overrun by E. coli or Salmonella, they can get sick.

With billions of dollars poured into space exploration each year by NASA and private companies like SpaceX, some researchers are concerned that a foodborne illness outbreak aboard the International Space Station could derail a mission.

In the new study by UD's team, published in Scientific Reports and in npj Microgravity, researchers grew lettuce in a weightless environment similar to that found at the International Space Station. Plants are masters of sensing gravity, and they use roots to find it. The plants grown at UD were exposed to simulated microgravity by rotation. The researchers found those plants under the manufactured microgravity were actually more prone to infections from Salmonella, a human pathogen. 

 Stomata, the tiny pores in leaves and stems that plants use to breathe, normally close to defend a plant when it senses a stressor, like bacteria, nearby, said Noah Totsline, an alumnus of UD’s Department of Plant and Soil Sciences who finished his graduate program in December. When the researchers added bacteria to lettuce under their microgravity simulation, they found the leafy greens opened their stomata wide instead of closing them.

“The fact that they were remaining open when we were presenting them with what would appear to be a stress was really unexpected,” Totsline said.

Totsline, the lead author of both papers, worked with plant biology professor Harsh Bais as well as microbial food safety professor Kali Kniel and Chandran Sabanayagam of the Delaware Biotechnology Institute. The research team used a device called a clinostat to rotate plants at the speed of a rotisserie chicken on a spinner.

“In effect, the plant would not know which way was up or down,” Totsline said. “We were kind of confusing their response to gravity.”

Additionally, Bais and other UD researchers have shown the usage of a helper bacteria called B. subtilis UD1022 in promoting plant growth and fitness against pathogens or other stressors such as drought.

They added the UD1022 to the microgravity simulation that on Earth can protect plants against Salmonella, thinking it might help the plants fend off Salmonella in microgravity. 

Instead, they found the bacterium actually failed to protect plants in space-like conditions, which could stem from the bacteria’s inability to trigger a biochemical response that would force a plant to close its stomata. 

“The failure of UD1022 to close stomata under simulated microgravity is both surprising and interesting and opens another can of worms,” Bais said. “I suspect the ability of UD1022 to negate the stomata closure under microgravity simulation may overwhelm the plant and make the plant and UD1022 unable to communicate with each other, helping Salmonella invade a plant.”

To contact researchers from the team, visit the profiles for Bais or Kniel and click on the contact button.


Research: Add space salad to the risks astronauts face

home-field-advantage-beneficial-bacteria-could-protect-turfgrass-from-damaging-disease

 Sports leagues from the pros on down use turfgrass because it's a hearty grass that can be mowed to exceedingly short heights and tolerates trampling foot traffic with ease. 

But it does have a shortcoming: Turfgrass is vulnerable to a pathogen called dollar spot. 

UD researchers Harsh Bais and Erik Ervin and doctoral student Charanpreet Kaur are part of a team studying the beneficial properties of UD1022, a UD-patented beneficial bacteria, to see whether it can be effective in protecting turfgrass. 

Left unchecked, dollar spot can result in huge economic losses for golf courses and other places where turfgrass must be managed and protected.

 Known as a growth promoter that can help plants flourish, the hope is that UD1022 can be a green alternative to complement existing turf-management processes already in use.

Bais, a professor of plant and soil sciences, is available for interviews and can be contacted by clicking on his profile below this photo or via his ExpertFile profile.  

Home field advantage: Beneficial bacteria could protect turfgrass from damaging disease

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