People around the world are donning masks right now to keep from inhaling the novel coronavirus. But plants have a more sophisticated way of keeping infectious diseases from entering their bodies. When they detect certain pathogens, plants will close the small openings on their leaves—akin to the pores on our skin—which are the access points for pathogens to enter into the plant and begin infection. But how exactly do the plants’ immune systems tell their stomata to close? A team of scientists led by Dr. Kathrin Thor have recently found that answer. An enzyme associated with the plant’s immune system causes the cells surrounding the stomata to collapse, compressing the stomata shut when a pathogen is detected on the leaf’s surface. The findings were published this August in the journal Nature.

   Plants’ stomata can close for a variety of reasons, such as diminishing sunlight. Yet, they all initiate the same chain of events. The chain starts with tiny gateways along the surface of cells that surround the stomata. These gateways control how much dissolved calcium can flow into and out of the cells. These are referred to as calcium channels. When calcium starts seeping in, the cells shrivel and collapse into the stomata. (Calcium channels might seem unusual, but they’re actually common in living things—being an integral reason our hearts function properly, for example). The gateways all control calcium flow, but they are each triggered by different stimuli. The authors carefully mutated a set of experimental plants to erase certain gateways. They then sprayed pathogens on them each time to see whether they were still able to close their stomata to save themselves from infection. Through this method, they pinpointed the exact gateway that grants entry to calcium when the plant detects a pathogenic threat.

   While plants do have this safeguard in place, it’s not perfect. Around 10% of crops each year are killed off by disease. That number may increase in the future as higher temperatures further encourage the spread of disease. By understanding how plants protect themselves, we can potentially engineer crops to have even better stomatal response to pathogens. Then plants could shut the door on even more infections.

Kathrin Thor is a post-doctoral fellow at The Sainsbury Laboratory in the UK.

Managing Correspondent: Jordan Wilkerson

Original Article: The calcium-permeable channel OSCA1.3 regulates plant stomatal immunity

Image Credit: flickr

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