Researchers at the University of Exeter, led by Professor Gero Steinberg, have provided new insights into the mechanism by which pathogenic fungi avoid the immune responses of the plants they attack.
This opens up a new area of research into plant-host interaction which could lead to the development of fungicides that can act before the plant is harmed.
Plants that come under attack from pathogens have an automatic immune response. Fungi get around this plant immunity by injecting proteins into the host plant cells. These ‘effector proteins’ enable the fungi to escape the plant’s immune system and allow the fungal cells to enter the plant unrecognised.
The Exeter scientists found that signalling organelles, known as ‘early endosomes’ act as long distance messengers in the fungi. They travel rapidly along long tube-like cells between the plant-invading fungal cell tip and the fungal cell nucleus. This rapid communication between the point of invasion and the fungal cell nucleus enables the fungus to produce the effector proteins that help evade the plant’s immune response from the moment the fungus enters the host tissue.
This signalling mechanism occurs very early in the fungal infection process, at a time when the fungi are most accessible to fungicide treatment. Disabling the process could result in a new generation of fungicides that are able to act before the fungus has damaged the plant.
Professor Steinberg said:
“Pathogenic fungi are a major threat to our food security – they can devastate crops and cost billions of pounds worth of damage. In fact, losses of wheat, rice, and maize to fungal pathogens, per year, are the same as the annual spend by US Department of Homeland Security – some 60 billion US dollars. As fast growing microbes, fungi adapt rapidly to anti-fungal treatments and so we need to develop new fungicides all the time. Our research has led to a better understanding of the mechanisms by which the intruder attacks and overcomes the plant defence. In order to efficiently protect crops, we must better understand molecular mechanisms like these that occur in the very earliest stages of infection.”
The research was supported by the Biotechnology and Biological Sciences Research Council.
The paper, ‘Long-distance endosome trafficking drives fungal effector production during plant infection’, is published in the journal Nature Communications.
This post is based on a a press release from the University of Essex.