Plants have a built-in off-switch for smoke germination signals
Li Q, Chang SH, Tuckey A, Sepulveda C, Varshney K
Plant Signaling
The same smoke chemistry that tells wildflower seeds to sprout after a burn turns out to have a built-in shutoff valve, which could help explain why some seeds germinate right on cue after fire while others hold back.
Certain plant seeds sense chemicals in wildfire smoke and use them as a cue to sprout. Researchers found that Arabidopsis plants make a protein called DLK2 that quietly breaks down that signal after it's done its job, acting like a brake so the germination response doesn't run out of control. This backup system works alongside another gene, and losing both at once makes plants stuck in constant 'smoke signal' mode.
Key Findings
DLK2 is an ancient paralog of the karrikin receptor KAI2 that forms a negative feedback loop attenuating karrikin/KL signaling in Arabidopsis
Loss of DLK2 alone has little effect, but combined with loss of KUF1 it synergistically produces constitutive karrikin-response phenotypes in seedlings
DLK2 hydrolyzes a profluorescent butenolide reporter molecule analogous to the karrikin ligand, suggesting it catabolizes the signal without directly participating in signaling
chevron_right Technical Summary
Scientists discovered a molecular brake that keeps a plant hormone signal from running too long. A gene called DLK2 breaks down the signal molecule itself, helping plants like Arabidopsis fine-tune their response to smoke-derived germination cues.
Abstract Preview
Original paper
Negative feedback regulation of karrikin signaling in Arabidopsis thaliana by an antagonistic paralog of karrikin receptors.
Karrikins (KARs) are a class of butenolide molecules discovered in smoke hypothesized to mimic an undiscovered plant hormone, KAI2 ligand (KL). KAR/KL signaling regulates germination, seedling deve...
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