Psyllids, related to those found harboring the new species of Liberibacter. Credit: UCANR
Key Points:
- Researchers stumbled upon L. capsica, a bacterium that belongs to a family of species that contributes to citrus greening.
- The bacteria have mutated to invade host insects and assimilate their DNA.
- L. capsica is known to infect plants, but there is no evidence yet to determine how harmful—or beneficial—the bacteria can be.
A team of scientists at UC Riverside is studying how a recently discovered bacteria is mutating to potentially kill crops. The bacteria, L. capsica, was discovered unintentionally by an entomologist in Brazil. The scientists, who published their study in Microbiology Spectrum, are issuing warnings to increase awareness in case of a possible outbreak.
L. capsica is a member of Liberibacter, a bacterial genus responsible for the destruction of commercially significant crops. Three species belonging to Liberibacter, for instance, are linked to Huanglongbing, or citrus greening. The disease is spread by small insects called psyllids and is a major threat to the citrus industry worldwide. Unfortunately, there exists no cure for the disease.
Scientists, therefore, are interested in L. capsica because of its genetic proximity to destructive species in the Liberibacter family. They are focusing on how members of the family mutate to be able to live inside a host.
After zeroing in on 21 L. capsica genes known for their infectious potential, the scientists discovered a subset of mutations on genes that affect pilus. Pilus are hair-like protein structures that allow cells to attach to surfaces. The L. capsica bacteria uses the pilus to enter hosts, reside in them, and assimilate their DNA. Insects then transmit the bacteria to plants.
Diana Percy, an entomologist who studies psyllids worldwide, discovered L. capsica after collecting insects she found on a pepper plant. Even though scientists know the bacteria enters host insects, there is currently not enough information to determine if they do the same to plants.
The research team, however, is erring on the side of caution.
“We’re informing scientists in Brazil and other places to screen plants for it,” said Allison Hansen, an entomologist at UC Riverside. “It should be on everyone’s radar for outbreak potential given the propensity of Liberibacter for being serious plant pathogens on domesticated crops.”
The scientists hope that understanding how these bacteria mutate will help agriculturists protect their crops, thereby protecting food security.