Research that goes beyond the lab for citrus, avocados, and bell peppers

How biotechnology, drones, and plant breeding are advancing agriculture

TECHNOLOGY has the ability to change the world, and it will likely be needed to protect it too. It’s a sentiment that those in Florida agriculture know all too well. With challenges like citrus greening, laurel wilt in avocados, and high consumer expectations for fruits and vegetables, Florida ag producers will look to technology and research to aid in such challenges.

One reliable source for innovation and breakthroughs in agrarian technologies and research is the Institute of Food and Agricultural Sciences at the University of Florida, or UF/IFAS. The program utilizes top-notch professors, researchers, and students to crack ag’s greatest problems. Naturally, they work closely with the produce and livestock that are near and dear to the hearts of Florida agriculture. Recent developments in three separate areas of research are a testament to how technology is helping propel Florida agriculture into the future.


Citrus greening is on the forefront of just about every Floridian’s mind as the HLB disease ravages the citrus industry. However, citrus producers and UF/IFAS researchers alike are not taking it lying down. The disease was detected 10 years ago in commercial citrus, and a cure or viable treatment is needed to save Florida’s $10.7 billion citrus industry. Researchers at UF/IFAS have been at the forefront of research and testing, and they just may be on to something.

UF/IFAS recently announced the culmination of research by plant cell genetics professor, Jude Grosser. Essentially, Grosser and his team have created citrus trees with enhanced resistance to the HLB disease by taking a gene from a mustard plant, NPR1, and inserting it into the DNA of sweet orange citrus trees. Grosser maintains that it is “comparable to an ‘immunization’ in humans.” Just like a measles inoculation teaches the body to recognize and fight the measles pathogen, the team’s research essentially adds “a gene from another edible plant that increases the citrus tree’s innate ability to fight off infection,” Grosser says. “This is a regulatory gene that enhances the citrus tree’s own defense mechanism called SAR (Systemic Acquired Resistance).” Grosser explains, adding, “With citrus greening disease, the causal bacteria somehow fools the citrus tree and does not elicit the full defense capacity available to the plant.”

The research that has been done thus far shows a glimmer of hope, as testing of juvenile trees in both greenhouse and field testing resulted in lower instances of positive tests for the greening bacterium. For instance, in greenhouse testing, 45 percent of the trees with the mustard gene tested negative for HLB; in field testing, various lines tested positive for the bacterium at a particular month’s sampling and then tested negative for the bacterium at a later sampling, as if the trees were overcoming the disease. Throughout the three-year field study, the citrus trees expressing the mustard gene remained healthy.

While Grosser’s young trees have not yet flowered or borne fruit, researchers believe that the regulatory gene could also fight additional citrus diseases. “The NPR1 gene elicits broad spectrum resistance to bacterial and fungal pathogens in other crops, so there is potential that it could help the citrus tree fight other important diseases such as canker and black spot,” Grosser shares. He also confirmed that testing the new trees’ resistance to other pathogens is in the works.

While the news is exciting, it’s a ways off from fighting citrus greening in commercial groves, Grosser points out. There’s much to be done; Grosser elaborates, “We are currently working to get this gene into the appropriate varieties for our industry, including a significant effort to bypass or minimize the engineered tree juvenility. This is needed to speed up the horticultural evaluation of the new trees, which is necessary to prove to our growers that we have not altered the yield or cultivar integrity of any the newly engineered tolerant/resistant varieties to be adapted by our industry.” He estimates that he believes growers could benefit from his team’s research in approximately 10 years.


Another product that’s important to Florida agriculture is avocados, and producers have their own problems with laurel wilt disease. Early detection is paramount to controlling the spread of the disease, and researchers have known for some time that they can detect infected trees through aerial photography. Associate Professor Reza Ehsani and his team have recently created an algorithm, which is a formula or procedure for solving a problem, to fight laurel wilt. The study looked at establishing optimal settings such as altitude, camera resolution and more that “describe how you can use a multiband aerial image to detect laurel wilt at an earlier stage,” Ehsani explains.

They identified factors such as which spectral bands to use — “to identify those bands that are able to detect the disease’s spectral signature,” Ehsani shares — and what kind of equipment would best suit avocado growers to take advantage of aerial photography in the field. Essentially, Unmanned Aerial Vehicles (or drones), were the weapon of choice. “Nowadays, unmanned aerial systems and UAVs are gaining in popularity. We think with the right type of camera, we can use this algorithm to detect laurel wilt at an earlier stage,” Ehsani explains. He added that the algorithm would allow detection at an asymptomatic stage, which cannot be detected with the naked eye. Avocado growers could utilize the algorithm as soon as legislation is passed to allow growers to use UAVs without a lengthy permit process, Ehsani explains.


Diseases and pathogens aren’t the only issues the researchers at UF/IFAS tackle. Consumers demand a lot from their produce, such as uniform shape, rich color, and satisfying flavor, and those expectations are ever increasing. Professor Bala Rathinasabapathi and his team of students with UF’s College of Agricultural and Life Sciences are currently working on improving peppers, an industry worth more than $200 million in Florida annually.

It’s all part of Rathinasabapathi’s “Building Better Peppers” research program, which allows undergraduate students to complete projects in plant breeding and genetics. Rathinasabapathi’s reasoning behind the project is simple: to make healthier consumers. “It is a challenge to make people choose more fruits and vegetables in their diet over many other junk-food options. One solution to this challenge is to breed a number of vegetable and fruit varieties that will provide a spectrum of attractive colors, shapes, size, taste, and flavor,” he explains.

“We believe that breeding varieties improved for nutrient content, taste, and flavors can increase consumers’ positive preference for vegetable and fruits and thus their health,” he shares, adding, “Ultimately, this I believe, will be the most important ‘public good’ contribution from horticulturists.”

As the “public good” is at the forefront of all the minds of responsible growers, technological advances, and research from UF/IFAS, consumers will be able to enjoy a glass of Florida orange juice, an avocado and a tasty bell pepper grown in the Sunshine State for generations to come.


article by ERIKA ALDRICH
photos by TYLER JONES

Posted January 12, 2016

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