Document Type


Publication Date



Plants are under constant attack by a suite of insect herbivores. Over millions of years of coexistence, plants have evolved the ability to sense insect feeding via herbivore-associated elicitors in oral secretions, which can mobilize defense responses. However, herbivore-associated elicitors and the intrinsic downstream modulator of such interactions remain less understood. In this study, we show that tobacco hornworm caterpillar (Manduca sexta) oral secretion (OS) induces reactive oxygen species (ROS) in tomato (Solanum lycopersicum) protoplasts. By using a dye-based ROS imaging approach, our study shows that application of plant-fed (PF) M. sexta OS generates significantly higher ROS while artificial diet-fed (DF) caterpillar OS failed to induce ROS in isolated tomato protoplasts. Elevation in ROS generation was saturated after ~140 s of PF OS application. ROS production was also suppressed in the presence of an antioxidant NAC (N-acetyl-L-cysteine). Interestingly, PF OS-induced ROS increase was abolished in the presence of a Ca2+ chelator, BAPTA-AM (1,2-bis(o-aminophenoxy)ethane-N,N,N0,N0-tetraacetic acid). These results indicate a potential signaling cascade involving herbivore-associated elicitors, Ca2+, and ROS in plants during insect feeding. In summary, our results demonstrate that plants incorporate a variety of independent signals connected with their herbivores to regulate and mount their defense responses.

Creative Commons License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.

Publication Title

International Journal of Molecular Sciences



Included in

Biology Commons



To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.