Physiological function and ecological aspects of fatty acid-amino acid conjugates in insects^†

† This review was written in response to the author’s receipt of the JSBBA Award for Young Scientists in 2015.

Abstract

In tritrophic interactions, plants recognize herbivore-produced elicitors and release a blend of volatile compounds (VOCs), which work as chemical cues for parasitoids or predators to locate their hosts. From detection of elicitors to VOC emissions, plants utilize sophisticated systems that resemble the plant–microbe interaction system. Fatty acid–amino acid conjugates (FACs), a class of insect elicitors, resemble compounds synthesized by microbes in nature. Recent evidence suggests that the recognition of insect elicitors by an ancestral microbe-associated defense system may be the origin of tritrophic interactions mediated by FACs. Here we discuss our findings in light of how plants have customized this defense to be effective against insect herbivores, and how some insects have successfully adapted to these defenses.

Graphical abstract

Fatty acid–amino acid conjugates (FACs) in caterpillar regurgitant triggers herbivore-specific plant defenses.

Keywords:

• tritrophic interaction
• FACs
• herbivore-associated elicitors
• VOCs
• microbes

Acknowledgments

The author thanks Professor Naoki Mori (Kyoto University) and Professor James H. Tumlinson (Penn State University) for their guidance and encouragement throughout the course of my research. I also thank my collaborators and colleagues, Dr Irmgard Seidl-Adams for kind support, helpful comments, and discussions.

Disclosure statement

No potential conflict of interest was reported by the author.

Notes

† This review was written in response to the author’s receipt of the JSBBA Award for Young Scientists in 2015.