Stomata: A missing link to understanding plant volatile communication

Monday, November 14, 2022

11:42 AM – 11:54 AM PT

Location: Vancouver Convention Centre, Meeting Room 211

Presenting Author(s)

Natalie M. Aguirre

Graduate Student
Texas A&M University
Hockley, Texas

Co-Author(s)

John M. Grunseich

Graduate Student
Texas A&M University
College Station, Texas
AH

Anjel Helms

Assistant professor
Texas A&M University
College Station, Texas

Corn plants (Zea mays) face attack by insect pests which requires complex defense mechanisms to combat herbivory. Upon herbivory by fall armyworm (Spodoptera frugiperda), corn plants release complex mixtures of herbivore-induced plant volatiles (HIPVs) into the air. The HIPVs enhance or “prime” the defense response of non-attacked, neighboring plants upon subsequent herbivory. Recent research identified key compounds within the fall armyworm-induced corn volatile blend that trigger a primed state in neighboring plants, but relatively little is known about the perception mechanism of these compounds. The goal of this study was to determine the role of stomatal pores in the perception of key volatile compounds. We predicted that specific HIPVs (indole or (Z)-3-hexenyl acetate) will not be perceived by corn plants when stomata are closed, preventing defensive priming from occurring. To test this hypothesis, we quantified herbivore defense phytohormone levels in plants exposed to indole or (Z)-3-hexenyl acetate or unexposed plants during various treatments to manipulate stomatal aperture. We found significant increases in phytohormone levels (JA and ABA) from HIPV-exposed plants compared to control when exposure occurred while stomata were open. Closed-stomatal exposures, however, resulted in no differences in JA and ABA compared to control. The defensive plant priming response by indole or (Z)-3-hexenyl acetate exposure did not occur when stomata were closed by darkness or drought. These results suggest stomata could serve as a port of entry required for the perception of key volatile compounds.