Photo courtesy of Zhonglin Mou, UF/IFAS
University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) researchers are putting genes from a non-citrus plant into Hamlin oranges to develop citrus plants that fight huanglongbing (HLB), also known as citrus greening disease. The newly developed plant is called NuCitrus. It’s based on a protein called Arabidopsis NPR1 (AtNPR1). The new citrus shows strong tolerance to HLB, 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, but they also produce high-quality fruit, said 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,” said Triplett, a co-lead author on a new 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,” said 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.”
Mou’s team is working to propagate 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 said. “I expect these lines to work well in well-managed groves where the latest nutritional advances and psyllid-control measures are in place.”
Psyllids are the insects that infect citrus with HLB.
“We are working with a nursery to expand the number of plants available quickly,” Triplett said. “This will take time to provide the scale needed. Approvals by the EPA (Environmental Protection Agency) and the Food and Drug Administration (FDA) for commercial use are expected in less than two years. A USDA (U.S. Department of Agriculture) permit has been granted for experimental use such as for yield trials.”
The pathogen-free plants will be available to growers once EPA and FDA approvals are obtained, Mou said.
Source: UF/IFAS
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