Sweet smells prepare plants for future stress: airborne induction of plant disease immunity.
Plants require protection against a wide range of attackers such as insects and pathogens. The adequate plant defense responses are regulated via sophisticated signal cascades, which are activated following the perception of specific cues of the attackers. Plants might, however, gain a significant fitness advantage when pre-empting enemy attack before it actually occurs. Monitoring cues from attacked neighbors can permit plants to reach this goal. We have recently found airborne disease resistance against a bacterial pathogen in uninfected lima bean plants when these were located close to conspecific, resistance-expressing neighbors. The emitters could be chemically induced with benzothiadiazole or biologically with an avirulent pathogen. Unexpectedly, receiver plants, although expressing a functioning resistance, did not show reduced growth rates, which represent a common side-effect of directly induced pathogen resistance. Nonanal was identified as an active volatile and, rather than directly inducing full resistance, primed defense gene expression, which became fully activated only when the plants were subsequently challenged by a virulent pathogen. Priming by airborne signals allows for a more efficient and less costly preparation of plants for future attack and airborne signaling can affect resistance against both major groups of plant enemies: herbivores and pathogens.
Yi
Hwe-Su
HS
Laboratory of Microbial Genomics, Industrial Biotechnology and Bioenergy Research Center, KRIBB, Daejeon, S. Korea.
Ryu
Choong-Min
CM
Laboratory of Microbial Genomics, Industrial Biotechnology and Bioenergy Research Center, KRIBB, Daejeon, S. Korea.
Heil
Martin
M
Departamento de Ingeniería Genética, CINVESTAV Irapuato, Irapuato, Guanajuato, México.
D000388:Air; D060467:Disease Resistance; D007887:Fabaceae / Q000187:drug effects / Q000276:immunology* / Q000382:microbiology*; D009812:Odorants; D010935:Plant Diseases / Q000276:immunology* / Q000382:microbiology; D057865:Plant Immunity / Q000187:drug effects; D044224:Pseudomonas syringae / Q000187:drug effects / Q000502:physiology; D013312:Stress, Physiological / Q000187:drug effects; D055549:Volatile Organic Compounds / Q000737:chemistry / Q000494:pharmacology
D055549:Volatile Organic Compounds