PHOENIX MOLECULE: Wildfire ash and smoke generate karrikins, which are sensed by a seed protein, KAI2, stimulating the growth of a new plant in the nutrient-rich ashes of its parents.JAMIE SIMON/THE SALK INSTITUTE FOR BIOLOGICAL STUDIESFires leave behind charred and blackened landscapes. But eventually life returns, sometimes more vibrantly than ever, as some plants thrive, taking advantage of a sun-flooded and largely competition-free environment.
In 1990, South African researcher Hannes de Lange showed that it might be more than increased access to sunlight, nutrients, and space that spurs the proliferation of certain plant species following fire. The secret to the success of these plants could lie in smoke. De Lange found that smoke could stimulate seeds of a fire-sensitive South African shrub to germinate. Nearly a decade ago, University of Western Australia researcher Gavin Flematti and colleagues were the first to identify a potent class of smoke compounds—dubbed karrikins after an Aboriginal word for smoke, “karrik”—that signal to seeds that it’s a good time to grow (Science, 305:977, 2004).
“The big mystery remained, how are [karrikins] recognized by plants?” says David Nelson, a geneticist at the University of Georgia ...
