To mark the first National Plant Health Week Professor Mark Banfield leader of the Plant Health Institute Strategic Programme at the John Innes Centre assesses recent developments in plant immunity and argues that we need to develop interdisciplinary approaches to meet the challenges ahead.
“Plant disease has shaped the natural and agricultural world. Perhaps the best-known example is the Irish potato famine in the mid 1800s where potato late blight disease (caused by the filamentous plant pathogen Phytophthora infestans) contributed to millions of deaths and mass emigration from Ireland.
150 years on, plant diseases are still a constant threat to global security. Between 30 and 40% of food we grow is lost to disease annually. In some localised outbreaks this can increase to 100% resulting in a breakdown in food security and in threats to civic society.
We have developed chemicals to control diseases such as late blight – potatoes are typically sprayed 15 times a year in Northern Europe. But these interventions are unsustainable because they damage biodiversity and are heavily dependent on oil for their production.
Our efforts over the past 25 years have concentrated on developing genetic forms of disease resistance in plants. Remarkable progress has been made in our understanding of the molecular basis of plant disease resistance mechanisms.
Plants have a two-layer immune system. The first layer involves detecting signatures of invading organisms on the cell surface via receptors which trigger a basic level of immune response; for example, stiffening the cell wall to prevent penetration of organisms or secreting molecules to resist the invader.
The second intracellular layer of immunity is called into action where the pathogen has evolved to circumvent the first layer of defence. Intracellular immune receptors detect signatures of adapted pathogens or pests. These signatures known as effectors are delivered inside cells to modulate host physiology to promote colonisation.
Activation of the second line of defence is more robust often involving cell death localised to the point of infection which means the pathogen is deprived of nutrients in the living tissue to proliferate so it dies.
What is becoming increasingly clear thanks to recent research, is that there is an interplay between the two layers of plant immunity to deliver overall disease resistance.
It means these two areas that have been studied separately in the past are starting to come together as an emerging field of study and one we need to understand more about in our efforts to engineer the plant immune system against disease.
For my team this this may mean making amino acid changes in proteins to form new receptors for recognising pathogens, a process more robust if we use precise technologies such as gene editing. For other researchers engineering may mean inserting a whole resistance gene from a wild grass species to see if it delivers resistance to wheat.
Recently we were pleased to contribute to an overview on immune receptor function at molecular level for the Journal of Biological Chemistry.
One of the interesting things about contributing to this thematic series called Plants in the Real World – is how it allowed us to explain concepts of the plant immune system to readers from different research backgrounds: biological chemists, structural biologists, biophysicists rather than people who are coming at it from an angle of plant pathology.
This is one example of a multi-disciplinary approach that we need to emphasise as part of Plant Health Week.
We need to encourage ways of bringing scientists from different disciplines together to try to build sustainable solutions; scientists who work on predicting climate change, plant pathologists studying the molecular mechanisms of disease and others who are tracking pathogens as they move around the world. In this way we can show what the threat is likely to be in the future and prepare.
Xylella fastidiosa is an example of a pathogen that has come into Europe from South America. It is adapting to the climate of Europe and because our climate in the UK is becoming more like that of Southern Europe then we want to be able to make sure that we are ready for this pathogen when it comes. There is excellent work going on in this area, for example, the BRIGIT programme that brings together a national collaboration led by the John Innes Centre.
It is an approach we ought to consider to other diseases such as wheat blast which has been moving from South America to Asia and has the potential to move across Europe. We need to be ready.
This means bringing people together in a research and development sandpit where there is funding available so we can generate ideas that perhaps would not occur in isolation.
This idea extends to the physical spaces we work in. The John Innes Centre is currently bidding for a new major infrastructure to modernise its current site.
I see major benefits in creating an interdisciplinary space which breaks down barriers so that everyone, particularly new arrivals, feel a part of the whole.
The other major barriers and where obstacles are put up is between us scientists working in research groups and the technology platforms. Platform technologies are sometimes embedded in labs due to historical reasons but bringing together technology platform areas of the new building will allow specialist support staff to integrate better and think about how their platform and the technologies could integrate with other ones and be a forward face to the science on site.
In my own work, in thinking about technology platforms I currently might think about the protein crystallography platform and the biophysical analysis platform which are directly associated with my science. I might not think about crop transformation so often, but if the whole of the platform technology is together then researchers might think more about all the facilities that are available.
All these things are in place now and there is no reason they should not happen at JIC (John Innes Centre) and TSL (The Sainsbury Laboratory) but I think there are ways we could work better, and the built environment can encourage that.
If we are going to tackle the challenges we face we are not going to do it with plant science alone. It needs chemists, physicists, engineers, people with experience in artificial intelligence and computer scientists. Virtually and physically we need to create the spaces where this happens.”