Using a microbe that occurs naturally in eastern cottonwood trees, scientists have boosted the ability of two other plants - willow and lawn grass - to withstand the withering effects of the nasty industrial pollutant phenanthrene.
And these plants can take up 25 to 40 percent more of the pollutant than untreated plants. The approach could avoid the regulatory hurdles imposed on transgenic plants - plants with genes inserted from or exchanged with other plant or animal species - that have shown promise in phytoremediation, the process of using plants to remove toxins from contaminated sites, according to Sharon Doty, associate professor of environmental and forestry sciences and corresponding author on a paper about the new work in Environmental Science & Technology
"Our approach is much like when humans take probiotic pills or eat yogurt with probiotics to supplement the 'good' microbes in their guts," she said. The microbe from the cottonwood was encouraged to colonize the roots of willows simply by dipping rooted and trimmed cuttings in solutions with the microbe. Grasses were treated with microbes in solution as seeds sprouted in soil.
Once integrated into the plants, the microbe supplemented their own microbial defenses. Microbes that take up residence in the inner tissue of plants and don't cause negative symptoms are called endophytes. In nature, endophytes have a welcomed, symbiotic relationship with plants. In polluted soil, for instance, if the right endophytes are present they consume toxins coming up through plant roots. The endophytes get fed and the plant gets help neutralizing pollutants that could kill it. That's been one challenge of phytoremediation: plants removing pollutants can, all too quickly, succumb to the toxins.