CRISPR gene editing could save Florida's struggling citrus industry

LABELLE, Fla. (WINK)—Florida's citrus industry is turning to gene editing in hopes of outsmarting citrus greening after years of sprays and trials haven't quite fixed the problem.

Researchers are using clustered regularly interspaced short palindromic repeats, or “CRISPR,” a gene-editing technology, to modify rootstock at the very base of citrus trees. 

Agricultural consultant Gene McAvoy has tried everything from netting to new treatments to combat the disease.

"Anything that we can do to that will help us be successful; we're willing to try," McAvoy said.

Growers are currently spraying heavily to combat citrus psyllid and greening, while adding extra fertilizer to compensate for the trees' inability to take up nutrients due to the disease. The new research focuses on modifying genes that already exist in citrus trees.

"CRISPR actually modifies genes that exist in the citrus tree," McAvoy said. "Using CRISPR, you could turn these genes on or off, so if there's a receptor that allows greening to enter the citrus tree, if you turn that receptor off, the bacteria can't get in."

The process starts with the rootstock, which is the base of the tree. The scion, which is a different variety of orange tree, such as Valencia or Hamlin, is grafted onto a rootstock, which provides benefits like tolerance to flooding or resistance to diseases like citrus greening.

"There are people who propagate citrus; they will grow root stocks," McAvoy said. "They'll actually take a bud from an own variety, like a Valencia, and that bud is just you can't hardly see it, but it's just a tiny little thing where a shoot would come from and using a knife… they cut the root stock, the stem of the root stock, and they insert this bud, and they wrap it with cello tape, and they will grow together."

The goal is to grow a tree that can hold its ground against greening. Some questions remain about how the gene-edited trees will perform compared to traditional oranges and about the flavor.

McAvoy remains hopeful about the potential impact of this technology.

"I'm hopeful it's a total success, and it's a home run, and allows us to turn the industry around," McAvoy said.