Bridging the Gap to the Tree of the Future

The University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) Citrus Research and Education Center hosted an OJ Break seminar on May 14. The speakers provided updates on developing a gene-edited citrus tree with resistance to HLB and how growers can use existing tools to mitigate the disease.

Nian Wang, UF/IFAS professor, provided an update on the status of his research that is utilizing CRISPR technology to develop HLB resistance. He noted that 200 genome-edited citrus lines are now under evaluation.

Wang also shared an interesting observation about allowing some shoots from the citrus rootstock to grow up into the canopy of the tree. Several popular rootstocks have shown improved tolerance to HLB. The concept is that those rootstock shoots could bypass the scion and transfer carbohydrates to the root system. This could improve root and canopy health.

Ozgur Batuman, UF/IFAS associate professor, presented ways growers might tap into existing practices to bridge the gap between now and a citrus tree that is resistant to HLB. He said that tree could be eight years away from being available to growers.

Batuman said much of what he presented had been developed by others throughout history. His timeline started with covering newly planted trees with individual protective covers (IPCs) that have been proven to help prevent HLB for about three years.

When the IPCs come off, Batuman suggested the use of systemic acquired resistance inducers and brassinosteroids to boost tree health and protect against HLB. Those materials, along with the use of trunk-injection therapies like oxytetracycline, could help groves remain healthy and productive out into that eight-year timeframe when improved HLB-resistant genetics could become available.

Batuman reminded growers there are no silver bullets — including a genetically modified or edited tree — because diseases have a way to develop resistance. Therefore, the tools he outlined as well as ongoing management of the Asian citrus psyllid remain vital for citrus production.