As farmers work tirelessly to recover from the impacts of the citrus greening disease, and doing so in the wake of multiple hurricanes that have further exacerbated their losses, researchers, too, are working diligently to develop innovative solutions.
Lukasz Steliniski and his team at UF/IFAS Citrus Research and Education Center are testing a new citrus tree that may be able to fight off the insects responsible for spreading the greening pathogen, Asian citrus psyllids.
The tree, which so far has shown immense success in laboratory trials, has been modified to include a gene that normally occurs in Bacillus thuringiensis (Bt), a soil-borne bacterium. The gene triggers the tree to make its own version of the protein, which then kills the psyllids by creating holes in its gut. Bt Genes have been used successfully in other crops. Bt Corn has been available to farmers since 1996. About 90% of the Corn grown in the United States is Bt Corn.
“It’s too early to say whether this could have a practical change or impact on the industry,” Stelinski notes, but he is optimistic that it could have success in a real-world setting.
“Under laboratory conditions, we have found that when trees express this protein, they will not support reproduction of the (psyllid) vector,” Stelinski says. “Yet even if it worked perfectly as we envisioned it might, it would not be an ultimate solution to the disease since it only focuses on the vector.”
The team is working to create larger numbers of the new trees that could, ideally, be planted later this year. Only then will they know whether the trees are successful in fighting off the vectors for the disease (the psyllids) in authentic field conditions. This will also help researchers determine whether other areas of citrus production are impacted by the new genetics. For example, Stelinski explains, “The trees could be perfect psyllid killers but not produce oranges as well, and that would render them useless.” Another challenge, of course, will be marketing fruit from these genetically-modified trees to consumers who are already wary about genetically modified alternatives.
Still, Stelinski’s research shows promise amid a torrent of other innovations that are also helping the industry rebound. Among these are antibiotic injections to decrease the bacteria load in trees that are already in the ground, along with plant hormones used to improve the growth of trees already infected with the bacteria.
“There’s also been some success in traditional breeding programs [with] traditionally bred lines of citrus that are more tolerant to the disease.”
As Stelinski notes, all of these will take time to show lasting results, and all of them cost money, the latter being a major challenge for growers who are already in “financial dire straits” after sustaining one hurricane after another over the past several years.
Yet with continued collaboration among farmers, scientists, and the rest of the industry, there’s hope that Florida’s iconic citrus groves could thrive again.