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ARS Home » Southeast Area » Gainesville, Florida » Center for Medical, Agricultural and Veterinary Entomology » Chemistry Research » Research » Publications at this Location » Publication #420442
Research Project: Regulation, Biosynthesis, and Function of Plant Chemical Defenses and their Role in Climate-Resilient Agriculture

Location: Chemistry Research

Title: The Airborne herbivore-induced plant volatile indole is converted to benzoxazinoid defense compounds in neighboring maize plants

Author
item Sorg, Ariel
item LUO, ZHIWEI - Purdue University
item Li, Qin Bao
item Roy, Kristin
item BASSET, GILLES - University Of Florida
item KIM, JEONGIM - University Of Florida
item Hunter Iii, Charles
item CHAPPLE, CLINT - Purdue University
item Rering, Caitlin
item Block, Anna

Submitted to: New Phytologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/30/2025
Publication Date: 2/25/2025
Citation: Sorg, A.M., Luo, Z., Li, Q., Roy, K.M., Basset, G.J., Kim, J., Hunter Iii, C.T., Chapple, C., Rering, C.C., Block, A.K. 2025. The Airborne herbivore-induced plant volatile indole is converted to benzoxazinoid defense compounds in neighboring maize plants. New Phytologist. https://doi.org/10.1111/nph.70004.
DOI: https://doi.org/10.1111/nph.70004

Interpretive Summary: When plants come under attack from insect pests they release chemical odors to let other plants know of the danger so they can prepare their defenses against the attackers. ARS scientists from Gainesville, FL in collaboration with scientists from the University of Florida, and Purdue University studied what happens to these airborne chemicals in corn, and how they work to increase defenses of neighboring corn against insect pests. Results from this study showed that one of these chemicals (indole) could be applied as a gas to corn and corn would convert it into anti-insect compounds that are toxic to insect pests. This research could lead to the development of preventative treatments farmers could use to preemptively treat corn in advance of expected pest threats.

Technical Abstract: 1) Herbivore-induced plant volatiles act as danger signals to prime defense responses in neighboring plants, yet in many cases the mechanism behind this priming is not known. Volatile signals may be recognized directly by receptors and/or converted into other active compounds. Here we investigate the metabolic fate of volatile indole, a known priming signal in maize (Zea mays), to determine if its conversion to other compounds could play a role in its priming function. 2) We identified benzoxazinoids as major products from volatile indole using Heavy isotope labeled volatile indole and Pathway of Origin Determination in Untargeted Metabolomics (PODIUM) analysis. We then used benzoxazinoid biosynthesis mutants to investigate their role in indole mediated priming. 3) Labeled volatile indole was converted into DIMBOA-glucoside in a bx2 (benzoxazinone synthesis2) dependent manner. The bx2 mutant plants showed elevated green leaf volatile (GLV) production in response to wounding and Spodoptera frugiperda regurgitant irrespective of indole exposure. 4) Thus, volatile indole is converted into benzoxazinoids, and part of its priming mechanism is due to the enhanced production of these phytoanticipins. However, indole mediated enhanced GLV production does not rely on the conversion of indole to benzoxazinoids, so indole also has other signaling functions.