PARENT SESSION
Oral Session # 21: Herbivory I: Susceptability and Resistance.
Presiding: D Lincoln
Tuesday, August 5. 8:00 AM to 11:30 AM, SITCC Meeting Room 200.

Ecological consequences of altered jasmonate signaling capacity in Nicotiana attenuata.

Halitschke, Rayko^*,1, ¹ Max Planck Institute of Chemical Ecology, Jena, Germany

ABSTRACT- The involvement of jasmonic acid (JA) and related compounds, collectively called jasmonates, in the activation of wound- and herbivore-induced responses has been shown in several plant species. In the wild tobacco plant Nicotiana attenuata the wound-induced accumulation of JA is specifically amplified by fatty acid – amino acid conjugates in the oral secretions of the main natural herbivores of N. attenuata, Manduca sexta and Manduca quinquemaculata. The activation of several direct and indirect defense responses in N. attenuata is mediated by the jasmonate signaling cascade. We isolated genes involved in jasmonate biosynthesis and manipulated the signaling capacity of N. attenuata by antisense expression of these biosynthetic genes. We used transformed N. attenuata plants as model ecological expression system to investigate the signal function of jamonates in N. attenuata′s defense response activation. Analysis of development of M. sexta larvae feeding on transformed plants revealed reduced resistance in plants impaired in JA biosynthesis which is mediated by reduced expression of direct (nicotine accumulation and protease inhibitor activity) and indirect (terpenoid volatile emission) defense traits.

Key words: Manduca sexta, induced defense, Nicotiana attenuata, jasmonic acid