A new way to make a plant immune

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A new way to make a plant immune

Just like people plants come across pathogens. In contrast to humans, plants do not have an adaptable immune system that comes up with a way to deal with each new virus, bacteria or fungus. A plant either recognises an intruder or it does not. This recognition is done by specific receptors that recognise pathogens. When a plant has the correct receptor to recognise the intruder, it sounds alarm quickly, and the intruder is stopped. Without a receptor to recognise them, a virus, bacteria or fungus has unlimited access to the plant.

Up to now plant breeders have relatively few tools to equip a plant with the needed immune receptors. One method is to cross the plant with a relative that already has the wanted immune receptor. Another is to adapt, to tweak, the immune receptor. So far, this tweaking occurs by making small changes in the pathogen-recognition part of the immune receptor. Leading to the detection of a slightly different pathogen than it did before. Now researchers from the UK showed a different method, with which they can adapt the immune receptor for each potential intruder.

The researches make use of the adaptable immune system of animals. This they target with making antibodies against the plant-pathogens. Just like every other antibody, these antibodies have a specific and an unspecific part. The scientist took the specific part of the antibody and used this to replace the pathogen-recognition part of the plant immune receptor. This resulted in an immune receptor that recognises the plant pathogen.

To test if it was working, the scientists made an immune receptor that recognises a florescent protein. After inserting this florescent protein-recognising immune receptor in the plant, they gave fluorescent proteins to the plant. An immune response in the form of cell death was observed on the site of the fluorescent protein application. In addition, application of a virus that also makes fluorescent proteins resulted in cell death without any spread of the virus.

This gives plant breeders a promising tool to equip plants with resistance against pathogens. Two things we should not forget though. Firstly, even with the possibility to precisely adapt immune receptors, it still takes at least 5-10 years before a farmer can grow these resistant crops. And secondly, to get the aimed for immune receptors into the plant, genetic modification is used. This is not accepted everywhere without restrictions.

Literature

Kourelis, J., Marchal, M., Kamoun, S. (2021) NLR immune receptor-nanobody fusions confer plant disease resistance. bioRxiv preprint doi: https://doi.org/10.1101/2021.10.24.465418