Volatile characterization of lychee plant tissues (Litchi chinensis) and the effect of key compounds on the behavior of lychee erinose mite (Aceria litchii)

Authors: ATAIDE, LIVIA - University Of Florida; Tabanca, Nurhayat; CANON, MARIA - University Of Florida; Schnell, Elena; Narvaez, Teresa; Cloonan, Kevin; Kendra, Paul; CARRILLO, DANIEL - University Of Florida; REVYNTHI, ALEXANDRA - University Of Florida

Submitted to: Biomolecules EISSN 2218-273X
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/30/2023
Publication Date: 6/2/2023
Citation: Ataide, L.M., Tabanca, N., Canon, M.A., Schnell, E.Q., Narvaez, T.I., Cloonan, K.R., Kendra, P.E., Carrillo, D. 2023. Volatile characterization of lychee plant tissues (Litchi chinensis) and the effect of key compounds on the behavior of lychee erinose mite (Aceria litchii). Biomolecules EISSN 2218-273X. 13:933. https://doi.org/10.3390/biom13060933.
DOI: https://doi.org/10.3390/biom13060933

Interpretive Summary: The invasive lychee erinose mite (LEM), first detected in Florida in 2018, poses a serious threat to the state’s lychee fruit industry. The microscopic mite infests young leaves, stems, and flowers, where feeding causes galls known as erinea and prevents fruit production. Despite early eradication efforts, LEM continued to spread, and is now found in all lychee-growing areas in south Florida. Currently, little is known about the chemical ecology of LEM and there are no known attractants or repellents. Therefore, scientists from the USDA-ARS (Miami, FL) and the University of Florida (Homestead, FL) conducted research to identify potential host-based attractants or host defensive compounds induced by LEM infestation. Volatile collections and GC-MS analyses were used to characterize the chemical profiles of uninfested and infested lychee tissues. This identified 58 volatile organic compounds (VOCs), of which nonanal, decanal, limonene, sabinene, beta-caryophyllene and ar-curcumene were the most abundant. In laboratory bioassays with these six VOCs, the chemical concentration significantly influenced LEM attraction, which was typically best with lower concentrations. Results of this study provide important information on the lychee volatiles attractive to LEM. Further research is needed to evaluate combinations of chemicals and optimal doses for development of a field lure that can be used in pest management programs for LEM.

Technical Abstract: Herbivore-Induced Plant Volatiles (HIPVs) are volatile signals emitted by plants to deter herbivores and attract their natural enemies. To date, it is unknown how lychee plants, Litchi chinensis, respond to the induction of leaf galls (erinea) caused by the lychee erinose mite (LEM), Aceria litchii. Aiming to reveal the role of HIPVs in this plant-mite interaction, we investigated changes in the volatile profile of lychee plants infested by LEM and their role on LEM preferences. The volatile profile of uninfested (flower buds, fruit, leaves and new leaf shoots) and infested plant tissue were characterized under different levels of LEM infestation. Volatiles were collected using head-space-solid phase microextraction (HS-SPME) followed by gas chromatography-mass spectrometry (GC-MS) analyses. Fifty-eight volatiles, including terpenoids, alcohols, aldehydes, alkanes, esters, and ketones classes were identified. Using dual-choice bioassays, we investigated the preference of LEM to uninfested plant tissues and to the six most abundant plant volatiles identified. Uninfested new leaf shoots were the most attractive plant tissues to LEM and LEM attraction or repellence to volatiles were mostly influenced by compound concentration. We discuss possible applications of our findings in agricultural settings.