Fungi evade the plant’s immune system by attacking the microbiome

ENGINEERINGNET.BE – The well-being of living organisms depends to a large extent on the bacteria and other microbes that live in and on the organism. The entire package of all these microbes is called the microbiome, which also occurs in plants.

Researchers from the Universities of Cologne and Utrecht focused on Verticillium dahliae, a notorious fungus that causes wilt disease in many plants, such as tomatoes, lettuce, olive trees, ornamental trees, flowers, cotton and potatoes.

Their study demonstrated that the fungus secretes the antimicrobial protein VdAMP3 to manipulate the plant microbiome as a purported effector.

Effector molecules normally target components of the host’s immune system, resulting in a reduced immune response. The researchers showed that microbes from the microbiome are also targeted.

When the fungus colonizes its host, VdAMP3 suppresses beneficial organisms in the plant microbiome. This leads to a malfunctioning microbiome. This disruption allows the fungus to complete its life cycle and produce offspring that multiply and start a new infection.

A year ago, researchers also found a molecule that did not work against competing fungi, such as VdAMP3, but against competing bacteria.

More knowledge about these types of mechanisms could help make plants more resistant to pathogens and develop better crop protection strategies.

With the world’s growing population, limited agricultural land and the need to reduce environmental impact and pollution, one of the primary goals of botanists is to increase crop yields and reduce our carbon footprint on the environment.

In follow-up experiments, the researchers hope to identify more effector proteins that are selective antimicrobials. They then re-scan Verticillium dahliae, but they also target other pathogens that have different infection strategies.

Uncovering how these molecules function, and how they can inhibit one microbe without another, is important for discovering new mechanisms for targeting microbes. This may eventually lead to the development of new antibiotics.