Native finger limes to the rescue
American citrus farms in Florida have been devastated by Citrus Greening Disease, one of the most destructive diseases of citrus worldwide. The insidious disease was originally thought to be caused by a virus, but is now known to be caused by bacteria. It has already killed thousands of acres of orange and grapefruit trees, and is currently threatening citrus farms in California, which produces 80 percent of the United States’ fresh citrus.
Now scientists from the University of California Riverside have found the first substance capable of controlling the disease – a peptide found in our very own Australian finger limes, a wild relative of commercially-grown citrus fruits which possesses a natural tolerance for the bacteria that causes Citrus Greening Disease.
The treatment was discovered by geneticist Hailing Jin after a five-year search, and effectively kills the bacterium causing the disease with a naturally-occurring molecule found in finger limes. This molecule, an antimicrobial peptide, offers numerous advantages over the antibiotics currently used to treat the disease. Unlike antibiotic sprays, the peptide is stable even when used outdoors in high heat, is easy to make and is safe for humans.
Currently, some growers in Florida are spraying antibiotics and pesticides in an attempt to save their trees from the bacterium that causes citrus greening. But antibiotics are temperature-sensitive, so their effects are largely reduced when applied in the hot weather. By contrast, the finger lime peptide is stable even when used in 50+ degree heat.
Finger limes are increasingly being sought after by the world’s top chefs, and the fruit’s tangy pulp is often compared to caviar due to its tiny bead-like appearance. The fruit has been used as both food and medicine by Indigenous Australians for thousands of years, and is rich in vitamins C and E and minerals such as potassium.
Already a delicious and nutrient-dense addition to sauces, sweets, drinks and salads, or even just as a zesty accompaniment to cheese and crackers or fresh oysters, now Aussie finger limes look set to be the saviour of the American citrus industry. Feeling proud much?