An international team led by scientists at the Sainsbury Laboratory in Norwich,UK, have transferred broad spectrum resistance against some important plant diseases across different plant families. This breakthrough provides a new way to produce crops with sustainable resistance to economically important diseases.
Food insecurity is driving the search for ways to increase the amount of food we grow, whilst at the same time reducing unsustainable agricultural inputs. One way to do this is to increase the innate ability of crops to fight off disease-causing pathogens. Increased disease resistance would reduce yield losses as well as reduce the need for pesticide spraying.
Breeding programs for resistance generally rely on single resistance genes that recognise molecules specific to particular strain of pathogens. Hence this kind of resistance rarely confers broad-spectrum resistance and is often rapidly overcome by the pathogen evolving to avoid recognition by the plant.
However, plants have another defence system, based on pattern recognition receptors (PRRs). PRRs recognise molecules that are essential for pathogen survival. These molecules are less likely to mutate without harming the pathogen's survival, making resistance to them more durable in the field. These essential molecules are common to many different microbes, meaning that if a plant recognises and can defend itself against one of these molecular patterns, it is likely to be resistant against a broad range of other pathogens.
Very few of these PRRs have been identified to date. Dr Cyril Zipfel and his group at the Sainsbury Laboratory in Norwich, UK, took a Brassica-specific PRR that recognises bacteria, and transformed it into the Solanaceae plants Nicotania benthaminia and tomato.
"We hypothesised that adding new recognition receptors to the host arsenal could lead to enhanced resistance," said Dr Zipfel.
Under controlled laboratory conditions, they test
|Contact: Andrew Chapple|
Norwich BioScience Institutes