Widespread Plant Immune Tactics

A survey of plant genomes reveals how different species trick pathogens into triggering their immune defenses.

Jef Akst
Jef Akst
Feb 22, 2016

This image shows the relative abundance of gene functions as determined by NLR sequence data. All of these genes are potential candidates for disease resistance in plants as they are implicated as targets for plant pathogens.TAGXEDO.COM, KSENIA KRASILEVANucleotide-binding domain, leucine-rich repeat receptors (NLRs) are key components of the plant immune response, binding to bits of pathogen—or bits of plant compounds that are altered by a pathogen’s presence—to trigger secondary immune cascades that fight the invaders or sometimes plant cell death. Some NLRs work in tandem with integrated domains that mimic a bacterial target, thereby “baiting” the pathogen to bind. (See how NLRs work with other parts of the plant immune response to fight pathogen invasion.)

Surveying the genomes of 40 plant species, including 19 crops, Ksenia Krasileva of the Genome Analysis Centre and the Sainsbury Laboratory at Norwich Research Park, U.K., and colleagues found such NLR fusions were common among flowering plants, occurring in multiple plant families. Follow-up analyses validated the fusions found in wild and cultivated varieties of wheat and brassicas. The results, published last week (February 19) in BMC Biology, could inform the fight against plant disease, revealing domains that likely mimic pathogen effector targets and providing details about which immune genes operate in which plant species.

“In the last year, we and others showed that plant NLR immune receptors can carry integrated domains that mimic authentic host targets of pathogen effectors,” coauthor Jonathan Jones of the Sainsbury Laboratory said in a press release. “Interestingly, the identity of such NLR-fusions overlaps significantly with effector targets revealed by other methods, and thus reveal some important new host components that might be targeted by effectors to promote susceptibility.”

“Our method for detecting variations in immune receptors across flowering plants revealed exciting new genes that might be important for plant health,” Krasileva added. “We hope that the NLR-fusions we uncovered will provide clues to the host proteins targeted by pathogens and that this information can be deployed to discover new sources of disease resistance.”