It's a battleground down there in the soil where plants and bacteria dwell.
Even though beneficial root bacteria come to the rescue when a plant is being attacked by pathogens, there's a dark side to the relationship between the plant and its white knight.
According to research reported by a University of Delaware scientific team in the September online edition of Plant Physiology, the most highly cited plant journal, a power struggle ensues as the plant and the "good" bacteria vie over who will control the plant's immune system.
"For the brief period when the beneficial soil bacterium Bacillus subtilis is associated with the plant, the bacterium hijacks the plant's immune system," says Harsh Bais, assistant professor of plant and soil sciences, whose laboratory group led the research at the Delaware Biotechnology Institute.
In studies of microbe-associated molecular patterns (MAMPs), a hot area of plant research, the UD team found that B. subtilis produces a small antimicrobial protein that suppresses the root defense response momentarily in the lab plant Arabidopsis.
"It's the first time we've shown classically how suppression by a benign bacteria works," Bais says. "There are shades of gray the bacteria that we view as beneficial don't always work toward helping plants."
In the past, Bais' lab has shown that plants under aerial attack send an SOS message, through secretions of the chemical compound malate, to recruit the beneficial B. subtilis to come help.
In more recent work, Bais and his collaborators showed that MAMP perception of pathogens at the leaf level could trigger a similar response in plants. Through an intraplant, long-distance signaling, from root to shoot, beneficial bacteria are recruited to forge a system-wide defense, boosting the plant's immune system, the team demonstrated. In that study, the Bais team also questioned the overall tradeoffs invol
|Contact: Andrea Boyle Tippett|
University of Delaware