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 involved in plants that are associated with so-called beneficial microbes.
In the latest work, involving the testing of more than 1,000 plants, the researchers shed more light on the relationship. They show that B. subtilis uses a secreted peptide to suppress the immune response in plants. It is known that plants synthesize several antimicrobial compounds to ward off bacteria, Bais says.
The team also shows that when plant leaves were treated with a foliar MAMP — flagellin, a structural protein in the flagellum, the tail-like appendage that bacteria use like a propeller — it triggered the recruitment of beneficial bacteria to the plant roots.
“The ability of beneficial bacteria to suppress plant immunity may facilitate efficient colonization of rhizobacteria on the roots,” Bais says. Rhizobacteria form an important symbiotic relationship with the plant, fostering its growth by converting nitrogen in the air into a nutrient form the plant can use.
“We don’t know how long beneficial bacteria could suppress the plant immune response, but we do know there is a very strong warfare under way underground,” Bais says, noting that his lab is continuing to explore these interesting questions. “We are just beginning to understand this interaction between plants and beneficial soil bacteria.”
The lead author of the research article was Venkatachalam Lakshmanan, a postdoctoral researcher in the Department of Plant and Soil Sciences; Sherry Kitto, professor of plant and soil sciences; Jeffrey Caplan, associate director of UD’s Bio-Imaging Center; Yu-Sung Wu, director of the Protein Production Facility; Daniel B. Kearns, associate professor in the Department of Biology at Indiana University; and Yi-Huang Hsueh , of the Graduate School of Biotechnology and Bioengineering at Yuan Ze University, Taiwan.
The research was supported by grants from the National Science Foundation.
See the original story, including a short animation, at http://www.udel.edu/udaily/2013/sep/soil-bacteria-092112.html
Andrea Boyle Tippett | Newswise Science News
New insight into why Pierce's disease is so deadly to grapevines
11.06.2018 | University of California - Davis
Where are Europe’s last primary forests?
29.05.2018 | Humboldt-Universität zu Berlin
Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.
Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...
The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.
Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.
An international team of scientists has discovered a new way to transfer image information through multimodal fibers with almost no distortion - even if the fiber is bent. The results of the study, to which scientist from the Leibniz-Institute of Photonic Technology Jena (Leibniz IPHT) contributed, were published on 6thJune in the highly-cited journal Physical Review Letters.
Endoscopes allow doctors to see into a patient’s body like through a keyhole. Typically, the images are transmitted via a bundle of several hundreds of optical...
Light detection and control lies at the heart of many modern device applications, such as smartphone cameras. Using graphene as a light-sensitive material for...
Water molecules exist in two different forms with almost identical physical properties. For the first time, researchers have succeeded in separating the two forms to show that they can exhibit different chemical reactivities. These results were reported by researchers from the University of Basel and their colleagues in Hamburg in the scientific journal Nature Communications.
From a chemical perspective, water is a molecule in which a single oxygen atom is linked to two hydrogen atoms. It is less well known that water exists in two...
13.06.2018 | Event News
08.06.2018 | Event News
05.06.2018 | Event News
15.06.2018 | Materials Sciences
15.06.2018 | Ecology, The Environment and Conservation
15.06.2018 | Power and Electrical Engineering