Induced root-secreted phenolic compounds as a belowground plant defense.
Rhizosphere is the complex place of numerous interactions between plant roots, microbes and soil fauna. Whereas plant interactions with aboveground organisms are largely described, unravelling plant belowground interactions remains challenging. Plant root chemical communication can lead to positive interactions with nodulating bacteria, mycorriza or biocontrol agents or to negative interactions with pathogens or root herbivores. A recent study suggested that root exudates contribute to plant pathogen resistance via secretion of antimicrobial compounds. These findings point to the importance of plant root exudates as belowground signalling molecules, particularly in defence responses. In our report, we showed that under Fusarium attack the barley root system launched secretion of phenolic compounds with antimicrobial activity. The secretion of de novo biosynthesized t-cinnamic acid induced within 2 days illustrates the dynamic of plant defense mechanisms at the root level. We discuss the costs and benefits of induced defense responses in the rhizosphere. We suggest that plant defence through root exudation may be cultivar dependent and higher in wild or less domesticated varieties.
Lanoue
Arnaud
A
Université François Rabelais de Tours, EA 2106 Plant Biotechnology and Biomolecules, 31 Avenue Monge, F-37200 Tours, France.
Burlat
Vincent
V
Schurr
Ulrich
U
Röse
Ursula S R
US
D002934:Cinnamates / Q000378:metabolism / Q000494:pharmacology; D005670:Fusarium / Q000187:drug effects / Q000472:pathogenicity*; D001467:Hordeum / Q000737:chemistry* / Q000382:microbiology; D010636:Phenols / Q000378:metabolism* / Q000494:pharmacology; D010935:Plant Diseases / Q000382:microbiology; D053147:Plant Exudates / Q000096:biosynthesis* / Q000494:pharmacology; D018517:Plant Roots / Q000737:chemistry* / Q000382:microbiology; D058441:Rhizosphere
D002934:Cinnamates; D010636:Phenols; D053147:Plant Exudates; C029010:cinnamic acid