Marine bacteria have found an unusual way to defend themselves against fungi

Scientists from the PIBOC FEB RAS and FEFU have discovered how the marine bacterium Vibrio jasicida inhibits fungal growth using a unique enzyme.

The bacterium was isolated from the gonads of the sea urchin Strongylocentrotus intermedius, which lives in the Sea of Japan. The researchers discovered that it produces a special type of chitinase, an enzyme that breaks down chitin (the main component of fungal cell walls and crustacean shells).

This enzyme, named ChitVjs, belongs to the GH19 family, a rare member of the Vibrio family. Its closest relatives are found in pathogenic bacteria that cause infections in humans and shellfish. However, ChitVjs has unique features: it is active only in the presence of salt (optimum 0.3-0.4 M NaCl) and operates at 40 °C and a neutral pH. In the laboratory, scientists reproduced the enzyme using genetically modified E. coli. They found that ChitVjs effectively inhibits the germination of spores of the marine fungi Aspergillus niger and A. fumigatus. Half the enzyme dose was required to stop A. fumigatus growth, likely due to the smaller size of its spores.

ChitVjs not only helps the bacteria extract nutrients from chitin but also serves as a weapon in the fungi battle for habitat in the marine environment. This discovery could find applications in biotechnology and the development of fungicidal drugs.

The results were published in the journal Microorganisms.