Atmospheric transformation of plant volatiles disrupts host plant finding

Abstract

Plant-emitted volatile organic compounds (VOCs) play important roles in plant-insect interactions. Atmospheric pollutants such as ozone (O3) can react with VOCs and affect the dynamics and fidelity of these interactions. However, the effects of atmospheric degradation of plant VOCs on plant-insect interactions remains understudied. We used a system comprising Brassica oleracea subsp. capitata (cabbage) and the specialist herbivore Plutella xylostella to test whether O3-triggered VOC degradation disturbs larval host orientation, and to investigate the underlying mechanisms. Larvae oriented towards both constitutive and larva-induced cabbage VOC blends, the latter being the more attractive. Such behaviour was, however, dramatically reduced in O3-polluted environments. Mechanistically, O3 rapidly degraded VOCs with the magnitude of degradation increasing with O3 levels. Furthermore, we used Teflon filters to collect VOCs and their reaction products, which were used as odour sources in behavioural tests. Larvae avoided filters exposed to O3-transformed VOCs and spent less time searching on them compared to filters exposed to original VOCs, which suggests that some degradation products may have repellent properties. Our study clearly demonstrates that oxidizing pollutants in the atmosphere can interfere with insect host location, and highlights the need to address their broader impacts when evaluating the ecological significance of VOC-mediated interactions.

Host Selection, Oviposition and Feeding by a Phytopathogen Vector, Diaphorina citri (Hemiptera: Liviidae), Modulated by Plant Exposure to Formic Acid

“…Volatile organic compounds (VOCs) and their oxidative breakdown products act as important semiochemicals in plantinsect interactions. Herbivorous insects use these chemical cues to differentiate between host and non-host plants (Li et al, 2016), and to locate feeding and oviposition sites. Previously, we reported that citrus volatiles such as β-ocimene and citral undergo oxidative breakdown in air and produce a number of smaller molecules including formic and acetic acids (George et al, 2016).…”

Biofiltration of airborne VOCs with green wall systems-Microbial and chemical dynamics

“…The VOC samples were desorbed on either a PerkinElmer ATD‐100 (Perkin‐Elmer Ltd., Waltham, MA, USA) (small chamber experiments and large chamber experiment 1) or a Markes TD‐100 (Markes International Ltd, Llantrisant, UK) (large chamber experiment 2), and analyzed by gas chromatography‐mass spectrometry (GC‐MS) [Hewlett‐Packard 6890 GC/5973 MSD (Wilmington, DE, USA) for the small chamber experiments and large chamber experiment 1; Agilent 7890A GC/5975C VL MSD (New York, USA) for large chamber experiment 2]. For a full description of thermal desorption and GC‐MS methods see Li et al . The compounds were identified using both authentic standards and the Wiley mass spectral database; concentrations of individual compounds were determined according to the calibration curves of authentic standards.…”

Metabolite database for root, tuber, and banana crops to facilitate modern breeding in understudied crops

“…Metabolomics can prove especially useful when tackling complex traits, that is those with many determinants, as the metabolome inherently reflects environmental factors and other stimuli such as chemical interactions. This is evidenced by the preference for elucidation of 'interactomes' such as the rhizosphere and volatile-ome of plants by incorporating deep sequencing of the microbiome (Hu et al, 2018;Jacoby and Kopriva, 2019) or atmospheric transformation of volatiles (Blande et al, 2014;Li et al, 2016b), respectively. Combining these measurements expands the biological system to the complete local environment and therefore characterization occurs at the ecosystem level.…”