Citrus greening, or huanglongbing, is a devastating disease for growers in the Southeast. Soilcea has deployed promising research out of the University of Florida to develop several HLB-resistant citrus rootstocks.
The company, which uses CRISPR technology, silences the rootstock’s interaction with Liberibacter, the bacterium that causes citrus greening and is vectored by the Asian citrus psyllid.
Soilcea CEO Yianni Lagos says this mode of action is natural and uses CRISPR to restore the trees’ natural defenses.
Lagos says research by Nian Wang at the University of Florida unlocked how the bacteria interact with the tree to turn off its natural defense mechanisms.
“It basically tricks the tree into not killing it,” he says. “And then we just turn off that interaction so the tree actively defends itself again.”
Soil-Specific Rootstocks Target Florida Ridge and East Coast
The company has released its CarriCea T1 rootstock; Lagos says it is a modified version of the Carrizo rootstock, which is the most popular citrus rootstock worldwide.
“It works really well in well-draining soil,” he says. “The Florida Ridge is very sandy. It’s higher up. That rootstock has historically performed extremely well there.”
Soilcea has also released Benicia D1, which is an edited version of US-812 rootstock, a hybrid of Sunki mandarin with trifoliate orange. Lagos says that rootstock is better suited for wetter soils.
“More on that east coast of Florida, you have wetter soils,” he says. “Carrizo hasn’t historically performed well there, but the edited US-812 — the Benicia D1 — should perform very well in those soils.”
Lagos says it was important for the company to release these two rootstocks to growers in desperate need of tools to fight greening.
“That’s why we’re really excited that the CarriCea T1 worked for us. Now it’s working for growers,” he says. “That’s exactly what we wanted to see. We’re really, really confident in how these rootstocks have been performing.”
A Decade of Research and Grower Collaboration
This hasn’t been an overnight success, Lagos says. The company, founded about 12 years ago, really began talking with Florida citrus growers almost a decade ago to discuss the goals of the company and to highlight the technology utilized.
“We’re really a known commodity now,” he says, acknowledging that spending that much time working with the growers to talk about the steps to introduction has helped growers really get on board.
Lagos says working closely with the University of Florida has also helped ground-truth the science for growers.
“There’s a lot of faith in some of the things that go on at the university,” he says. “That’s really helped that we were able to leverage the basic research from the University of Florida and use that basic research to create these trees.”
Lagos says it’s an exciting time where science and biology have converged and whole genome sequencing has become something that’s easy to do, whereas it would have been a challenge even 10 years ago.
Expanding Beyond Florida to Texas and California
Lagos says the plan for the future is to continue to expand in Florida, thanks to the help of the Citrus Research and Field Trial (CRAFT) Foundation, which incentivizes growers to plant these new HLB-resistant rootstocks.
Soilcea also plans trials in Texas and California as a preventative measure.
“When you put a tree in the ground, you want it to be in the ground for 30 years — and hopefully [citrus greening] never gets to the commercial groves in California, but in case it would, that would be a really great insurance that they would have,” he says.
Lagos says the company is working with additional rootstocks to provide more HLB-resistant options in the future. Soilcea is also looking at other diseases that affect citrus production. This includes early work on a citrus scion that shows some canker resistance, which he says will hopefully provide more solutions for growers who have suffered greatly from citrus greening.
“If there’s not a solution to this disease, there’s going to be no more oranges grown in Florida,” he says. “And this disease is spreading in Texas and California and all over the world, so there needs to be a solution for this or we’re just not going to have oranges. So, it’s really crucial.”
And Lagos says that by using CRISPR gene editing, Soilcea’s naturally created rootstock is something that the industry can highlight to consumers.
“Consumers can be comfortable with what we’re doing because we really are just mirroring nature,” he says.
