Plant cells identify pathogens and react to them by producing a burst of reactive oxygen, which is toxic to bacteria or fungi.


Cells around an infected site will then go into programmed cell death to seal off the disease. A research team from University of California, Davis (UC Davis) has now identified a key step in how plant cells respond to pathogens and identified a family of kinase enzymes that activate the enzymes that make reactive oxygen.


The UC Davis team has now isolated an enzyme, SIK1, in Arabidopsis that is considered the "firing pin" of plant immunity. SIK1 connects the receptors which detect pathogens to the reactive oxygen that kills them. The researchers found that when SIK1 was deleted, the plants were unable to make enough reactive oxygen and were more susceptible to infections. The team is now looking for homologs of SIK1 in crop plants. They want to know if the gene can be tuned up to boost resistance to pathogens in crops, leading to new treatments for plant diseases and breeding of crops that are more resistant to infections.


More details in the UC Davis Blogs.




Figure: The SIK1 protein links plant cell membrane receptors that detect pathogens (left) to enzymes that produce reactive oxygen that attacks and kills them (right). (Coaker lab, UC Davis)