Crop resilience: How does process of DNA repair enhance plant immunity?

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A multi-institution, international study led by Texas A&M AgriLife Research will investigate how a process that triggers DNA repair in plants also plays a role in strengthening their disease immunity.

Understanding key functions of the process, which is well-studied in humans, will help scientists design better disease-control strategies for highly resilient food crops, said Junqi Song, AgriLife Research assistant professor of plant pathology in Dallas. Song leads the $1.1 million National Science Foundation grant project alongside Ping He, Texas A&M University Presidential Impact Fellow and professor of biochemistry and biophysics in Bryan-College Station.

When invading pathogens infect plants, the enzyme poly(ADP-ribose) polymerase attaches the molecule poly(ADP-ribose), or PAR, to certain proteins. This process is PARylation, and it activates a number of responses to pathogens, including DNA repair, immune responses and cell death, among others.

The NSF grant’s official title is “Molecular dissection of protein poly(ADP-ribosyl)ation in plant immunity and pathogen-induced DNA damage”.

“We are most interested in the link between DNA repair and immune responses,” said He. “We know a lot about how they function individually. But new evidence suggests that PARylation could be a mechanical link between them.”

This is the crux of their research, and it is most likely applicable to all crop plants. Among crops, Song said, PARylation and plant immune response are genetically well conserved, or largely universal.

PARylation has been studied extensively in humans, due to its profound medical impact on many inflammatory and malignant disorders, namely cancer and related chemotherapy, he said.

“But the function of PARylation in plants is poorly understood,” Song said.

Over the next two years, Song and He — along with collaborators at academic and research institutions across the globe — aim to identify how PARylation targets immunity genes and proteins. By determining the intricately connected functions of DNA repair and immune responses, they will gain insight into how PARylation protects DNA from pathogen damage throughout an entire plant.

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