Plants are both components of ecosystems as well as the basis for the nutrition of an increasing world population. However, plants permanently cope with attack from thousands of insect and microbe species, and consequently have evolved complex strategies to repel these attackers. A detailed understanding of the mechanisms of the interactions between plants and insects will help to develop sustainable agriculture. Scientists of the Max Planck Institute for Chemical Ecology in Jena, Germany, gained new insights into the fundamentals of chemical signaling within the plant after herbivore attack and in doing so have highlighted the value of genetically modifying plants for the study of complex ecological interactions in nature. They produced transgenic Nicotiana attenuata (wild tobacco) plants which were silenced in the expression of an lipoxygenase-encoding gene that mediates oxylipin signaling and therefore were unable to defensively respond to insect attack. As expected, when these unresponsive plants were planted into their native habitat, they were heavily attacked by N. attenuata's established herbivores. However, herbivore species that were new to N. attenuata were also found to feed and reproduce successfully on the transgenic plants, revealing that lipoxygenase-dependent signaling determines host selection for opportunistic herbivores and that induced defenses influence herbivore community composition (Sciencexpress, 1 July 2004).

Scientists agree that a deep understanding of the ecological interactions that occur in nature is essential for sustainable agriculture and that the plant traits that are important for resistance to herbivore attack in nature are complex and operate on many spatial scales. They involve both direct defenses (toxins, digestibility reducers etc), that themselves protect plants as well as indirect defe
'"/>

Contact: Prof. Dr. Ian T. Baldwin
baldwin@ice.mpg.de
49-364-157-1101
Max-Planck-Gesellschaft
5-Jul-2004