The Florida citrus industry is fighting an epidemic that has reduced its yield by about half in the last 15 years. A molecular geneticist at the University of California, Riverside has secured a four-year grant aimed at halting the spread of a deadly bacterial disease that continues to spread among California’s citrus trees. The award of nearly $4 million, which comes from the National Institute of Food and Agriculture of the U.S. Department of Agriculture, will help cure citrus trees affected by huanglongbing disease, or HLB, and protect healthy trees from infection.
The research team led by Hailing Jin, the grant’s principal investigator, aims to achieve this goal by developing therapeutic and preventive solutions using a novel class of citrus-derived antimicrobial “peptides”— naturally occurring chains of amino acids found in all living organisms.
“HLB has no cure so far,” said Jin, a professor of microbiology and plant pathology, who holds the Cy Mouradick Endowed Chair at UCR and is a member of the university’s Institute for Integrative Genome Biology. “We have already identified a novel class of peptides by studying HLB-tolerant close relatives and hybrids of citrus. These peptides can directly kill the HLB bacteria and inhibit their spread in HLB-affected trees. They can also induce plant immune responses to protect trees from future HLB infection.”
To date, the disease has been controlled by planting HLB-free citrus germplasm, swiftly eradicating infected citrus plants, and using systemic insecticides on the Asian citrus psyllid. The University of California’s Citrus Clonal Protection Program, located in Riverside, provides a mechanism for the safe introduction of pest- and disease-free citrus germplasm into California, where the best strategy so far to keep the disease at bay is the application of insecticide treatments to prevent the psyllid’s spread into citrus-growing regions.
“These approaches, however, cannot totally control the disease and do not directly kill the HLB bacteria,” Jin said. “Our approach not only kills the bacteria in affected trees but it can also potentially serve as a vaccine for young, healthy citrus trees.”
Jin explained that the peptides her lab has identified are cost-effective, stable at high temperatures, and easy to synthesize. They work better than antibiotics, she said, and are safe, being derived from close relatives of citrus, such as the long-consumed Australian finger lime. The peptides are also effective at killing zebra chip disease bacteria that can threaten the potato industry.
Source: news.ucr.edu
