Scientists find potential key to plant immunity

Scientists at Edinburgh University have made a discovery which could help secure future global food supplies with the growth of disease-resistant crops.

The isolation of a specific process in the defence mechanisms of plants could also potentially aid the study of immune-related disorders in humans.

Professor Gary Loake led the team of scientists in their research and the findings have been published in the journal Nature.

Plants are regularly attacked by disease-causing organisms, and in one method of defence the plant kills all of the threatened cells in an attempt to starve-out the invader. Professor Loake and his team now understand the mechanics of this method and as a result have brought to light a particular enzyme, NADPH oxidase.

NADPH oxidase is critical in the creation of a class of molecules known as ‘reactive oxygen intermediates’ (ROIs), which a plant can release along with the chemical nitric oxide to attack the invading organism and encourage its own cells to shut down. ROIs include the likes of hydrogen peroxide and "free radicals".

The key to controlling the process lies in a feedback loop which causes ROIs to deplete and cell death to tail-off.

Prof Loake told The Journal: “We’ve been able to show how [NADPH oxidase] is regulated in a normal immune response. We hope that plant breeders will be able to use this information to develop disease-resistant varieties”.

Professor Douglas Kell, chief executive of the Biotechnology and Biological Sciences Research Council, contributed towards the research's funding. He said: “If available nutrition cannot meet the rise in global population we will face a crisis."

“We must find out as much as possible through studies such as this one, about how plants deal with invading pathogens so that we can develop new strategies to reduce the impact of disease on yields”.

On the potential benefit to humans of these findings, Prof Loake said: “We know that if a human being makes NADPH oxidase that doesn’t work properly then they can suffer from an immune deficiency called chronic granulomatous disease or CGD.”

Prof Loake confirmed that the discovery "might also open new opportunities to treat [such] human immune disorders.”