A smart one-two reaction
After recognition of pathogens by plants, often a lot of things simultaneously takes place. Everything to react as soon as possible. Now American and Dutch researchers show that plants initiate the first response to intrudes using a smart one-two like reaction.
An alarm is useful to be notified when something goes wrong. But when thereafter an alarm keeps sounding, then it more likely has a negative than a positive effect. This is the same for the first alarm that plants gives by recognition of pathogens. That alarm is short but intense. But how the plant is regulating this was still unknown. Now researches decided to investigate this.
The alarm signal that is sounded by plants takes the form of a small messenger, PA, which is activating the first line of defence. The researchers discovered that one of the PA producers, DGK5, is working together with one of the pathogen recognisers. When there are pathogens present then this recogniser is turning DGK5 on. This so observed the researchers resulted in more PA.
Using a smart one-two reaction the plant sounds the alarm, and turns this off again
But after detailed studying of DGK5 the researchers noticed something else. That after the turning on of DGK5 by the first pathogen recogniser, a second pathogen recogniser comes along and turns DGK5 off again. This resulted in that for a short time only extra PA is produced. In absence of DGK5 the plant could not react to pathogens. A similar reaction did the researchers observe by absence of the first pathogen recogniser. But was the second pathogen recogniser absent, then the production of PA stayed high.
This smart one-two reaction of pathogen recognisers makes sure that the plant sound the PA alarm. Turning on the first defence response. But because the plant is almost directly turning off this alarm, the PA-messenger is not getting in the way of the rest of the defence reaction.
Literature
Kong et al., (2024) Dual phosphorylation of DGK5-mediated PA burst regulates ROS in plant immunity, Cell https://doi.org/10.1016/j.cell.2023.12.030
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