Scientists Probe Protein Power as New Way To Fight Citrus Greening

It has been more than 20 years now since citrus greening was discovered in Florida. In that time, the systemic disease has reduced crop output exponentially. There is still no cure, but University of Florida scientists continue to search for answers and possible new solutions. Their latest endeavor includes using genes from another plant and putting them into Hamlin oranges to develop citrus plants that fight the disease. They have developed a plant they’re calling NuCitrus. It’s based on a protein called Arabidopsis NPR1 (AtNPR1). This new citrus shows strong tolerance to citrus greening, but not resistance.

Tolerance means plants can be infected by the pathogen but show no symptoms or only mild symptoms, which do not affect yield or quality. Resistance means that the plant can barely be infected.

NuCitrus plants not only tolerate disease attacks, they produce high-quality fruit, according Eric Triplett, a UF/IFAS Professor and Chair of Microbiology and Cell Science. The added gene in NuCitrus produces a natural protein that is common in many foods such as broccoli and cauliflower.

“Working with the UF/IFAS Crop Transformation Center, NuCitrus was developed by adding a gene to citrus that boosts its own natural defense system,” says Triplett, a co-lead author on the new research paper.

“Our recent paper shows that very little of this protein is found in NuCitrus fruit, it’s not toxic to humans, and, if eaten, is rapidly digested in the stomach, just as it is with other vegetables that contain it,” adds Zhonglin Mou, a UF/IFAS Plant Immunity Professor and lead author of the paper. “The added protein is not even toxic to the microorganism that causes citrus greening disease.”

Now, Mou’s team is working to propagate lots of NuCitrus plants from the existing ones for large-scale field testing and to obtain federal approval to use NuCitrus for high-quality orange juice in the future.

“I expect NuCitrus lines to become an important tool in the toolbox in the battle against the disease,” Triplett says. “I expect these lines to work well in well-managed groves where the latest nutritional advances and psyllid-control measures are in place.”

For more, continue reading at news.ufl.edu.