Plant & zo
The science of plants and more
Heat gives infections a chance
Through higher temperatures due to climate change plants get into more trouble. They get stressed faster. By heat. By drought. But also, it makes them more infection prone. At higher temperatures, the immune response upon pathogen infection does not happen. Giving the pathogens free access. The increasingly common occurrence of heatwaves is a threat to plant immunity. But how heat blocks the immune reaction is still unclear.
By infection an infection-manager takes charge. Directing the actions against the threat. On local level: cell death, blocking pathogens access to the rest of the plant. But also, by sending messengers to the rest of the plant, telling: be ready for action, there is an intruder. But by high temperatures, the infection-manager is nowhere to be seen. American researchers noticed one of the reasons the immune response did not start, there was not enough SA, salicylic acid.
The cause? That is what the researchers wated to know. The first suspects were the temperature sensors. But plants without working temperature sensors still don’t react to pathogens at high temperatures. The temperature sensors are not preventing the immune reaction. Neither does SA, when forcingly produced there is still no action from the infection-manager at high temperatures.
But by heat these proteins rather stay apart, leaving the gene switched off
Something still prevented the infection manager. To find out what, the researchers took a step back. Focussing on two gene-activators of the SA-production genes. How do they react. At high temperatures, it turned out, not much. But they gave the researchers a starting point. These gene-activators have in turn two switch on-buttons, both of which need to be turned on. One button is coupled to the recognition of pathogens. While the until now unknown other button is coupled to heat.
This last button is working in a surprisingly simple way. To turn this button on, three proteins need to come together on the button. But by heat these proteins rather stay apart. The gene stays off, even when pathogens are recognised.
The two gene-activators of the SA-production genes turned out to be the infection-managers. Although they are delegating a lot to SA. There will be no reaction in absence of the infection-managers, not even from SA. We can make plants better equipped to deal with the heat now we know how heat interferes with the immune response. So that plants can defend themselves, regardless of the temperature.
Literature
Kim, J.H., Castroverde, C.D.M., Huang, S., Li C., Hilleary R., Seroka A., Sohrabi R., Medina-Yerena D., Huot B., Wang J., Nomura K., Marr S.K., Wildermuth M.C., Chen T., MacMicking J.D., He S.Y. (2022) Increasing the resilience of plant immunity to a warming climate. Nature https://doi.org/10.1038/s41586-022-04902-y
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