from the teeny-weeny-little-bandaids® dept.
A team of researchers at the University of Toronto has successfully tested a new strategy for identifying genetic resources critical for the ongoing battle against plant pathogens such as bacteria, fungi, and viruses that infect and destroy food crops worldwide.
"As much as 40 per cent of global crop yield annually is lost to pests and pathogens such as bacteria, viruses and other disease-causing microorganisms," said David Guttman, a professor in the Department of Cell & Systems Biology (CSB) at the University of Toronto and co-author of a study published in Science. "In Canada, pathogens of the top five crops cause annual losses of approximately CDN $3.2B, even with no significant outbreaks."
[...] "Effectors play key roles in disease since they evolved to enhance the ability of pathogens to attack and infect their hosts. Fortunately, plants have evolved counter-defenses in the form of immune receptors that can recognize certain effectors," said Desveaux. "A plant is able to mount an 'effector-triggered' immune response that usually stops the infection, if it carries a specific immune receptor that recognizes a specific pathogen effector. This effector-receptor interaction has been called gene-for-gene resistance, and is the basis for nearly all agricultural resistance breeding."
The team started by sequencing the genomes of approximately 500 strains of the bacteria Pseudomonas syringae (P. syringae), which causes disease on nearly every major crop species.
"From these bacterial genomes we identified approximately 15,000 effectors from 70 distinct families," said Guttman. "We then reduced this complexity by identifying 530 effectors that represent their global diversity."
[...] "We found that over 11% of the effectors elicited immune response, and that almost 97% of all P. syringae strains carry at least one immune-eliciting effector," said Desveaux. "We also identified new plant immune receptors that recognize these effectors, and found that almost 95% of all P. syringae strains can be blocked by just two A. thaliana immune receptors."
[...] "While wild plant species have a diverse array of immune receptors, most domesticated crop species have lost much of this immunodiversity due to intensive artificial selection," said Guttman. "Our approach enables the rapid identification of new immune receptors in wild relatives of crops that can then be moved into elite agricultural lines by traditional breeding, ultimately creating new varieties with greater ability to resist agricultural pathogens."
Bradley Laflamme et al. The pan-genome effector-triggered immunity landscape of a host-pathogen interaction, Science (2020). DOI: 10.1126/science.aax4079