An international team of scientists has discovered a new antibiotic deep in the tropical forests of Mexico. The antibiotic, called phazolicin, may help lead to a new plant probiotic as well as new antibiotics, both of which could help in the fight against antibiotic resistance.
Found in the rainforests of Los Tuxtlas in southern Veracruz, phazolicin prevents harmful bacteria in the soil from damaging the roots of Phaseolus vulgaris, or wild beans, which gives it its name. But its potential as a plant probiotic could have much wider applications than on just beans.
"We hope to show the bacterium can be used as a 'plant probiotic' because phazolicin will prevent other, potentially harmful bacteria from growing in the root system of agriculturally important plants," said senior author Konstantin Severinov of Rutgers University in a statement.
When we think of probiotics, we tend to think of the helpful bacteria that live in our gut, balance the good and bad microbes, and help keep us healthy. Plant probiotics do the same thing, boosting resistance against harmful bacteria and disease. They can help plants become more resilient, which can lead to the use of fewer pesticides, if the plants can fight against disease, pests, or damage without the need for chemical assistance.
The bacterium that produces phazolicin is a new species of Rhizobium. Like other rhizobia, it forms nodules on the roots of bean plants, providing them with nitrogen and making them more robust in the process. However, unlike other rhizobia, the phazolicin-producing microbes defend the plants against harmful bacteria that are sensitive to phazolicin. The researchers think this could be used in the future to protect other legumes that are produced on a large agricultural scale, like peas, chickpeas, lentils, soybeans, and peanuts.
The new probiotic doesn’t just have applications as a biocontrol agent for use in agriculture, it could lead to new antibiotics too. Describing their discovery in the journal Nature Communications, the researchers found that the antibiotic binds to and targets the bacteria's ribosomes, the protein-manufacturing components in bacterial cells. They found that by introducing mutations into the ribosome they could determine and control the bacteria's reaction to the antibiotics.
"Antibiotic resistance is a huge problem in both medicine and agriculture, and continuing searches for new antibiotics are very important as they may provide leads for future anti-bacterial agents," Severinov said.
Antibiotic resistance is one of the biggest challenges humanity faces today. The discovery of penicillin in 1928 changed the world, shifting the leading cause of death away from infectious diseases that wiped out millions, allowing them to be easily treated and extending the average lifespan by around two decades. However, several strains of bacteria have evolved to become immune to antibiotics, both naturally and through the overuse and misuse of drugs in medicine and agriculture making them less effective, meaning infections like pneumonia, tuberculosis, and gonorrhea are on the rise again. This new discovery raises hopes that elusive new antibiotics can still be found, and eventually developed and brought to market before we actually run out.
