Research Reveals How Rice Plants Detect Pathogens

Certain types of plants can fight off plant killers, or pathogens--but not others, according to a mid-20th century model called the "gene-for-gene" hypothesis, developed by scientist Harold Henry Flor. New research from the UK's John Innes Centre and others bring great detail to Flor's model, showing how a plant senses a pathogen.

"We know that plants have sensors to detect pathogens but we knew little about how they work," Professor Banfield, lead researcher from the John Innes Centre (UK), said in a statement.

Their study, recently published in eLife, investigated how a sensor protein in rice (called Pik) binds with AVR-Pik, a protein from the rice blast pathogen. The latter is a fungus that causes rice's most devastating disease. The team used X-ray crystallography facilities at Diamond Light Source in Oxfordshire, from which they were able to identify the contact points between the plant and pathogen proteins at the molecular level. This is the first imagery that has been done for a pair of plant and pathogen proteins that follow the gene-for-gene model.

"Harold Flor predicted that plant sensors discriminate between different pathogen types, but at the time he had no knowledge of the molecules involved. It is remarkable that his ideas have now crystallized into detailed molecular models," explained first author of the study, Dr. Abbas Maqbool.

The team also found that the strength at which the Pik sensor binds with the pathogen AVR-Pik protein correlates with the strength of the plant's response, meaning that plant responses can be engineered to better fight against pathogens. By building sensors with increased strength of binding to pathogen proteins, plants would be able to enhance their resistance to diseases.

"Once we understand how these plant sensors detect invading pathogens, we can devise strategies to 'boost' the plant immune system and help protect rice and other important food crops from disease," Professor Banfield said.

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