| Title: | Wounding-Induced VOC Emissions in Five Tropical Agricultural Species |
| Author(s): | Portillo-Estrada M; Okereke CN; Jiang Y; Talts E; Kaurilind E; Niinemets U; |
| Address: | "Research Group Pleco (Plants and Ecosystems), Department of Biology, University of Antwerp, 2610 Wilrijk, Belgium. Chair of Crop Science and Plant Biology, Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, 51006 Tartu, Estonia. College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China. Estonian Academy of Sciences, Kohtu 6, 10130 Tallinn, Estonia" |
| DOI: | 10.3390/molecules26092602 |
| ISSN/ISBN: | 1420-3049 (Electronic) 1420-3049 (Linking) |
| Abstract: | "Leaf mechanical wounding triggers a rapid release-within minutes-of a blend of volatile organic compounds. A wounding-induced VOC blend is mainly composed of oxygenated ubiquitous stress volatiles such as methanol and volatile products of lipoxygenase (LOX) pathway (mainly C5 and C6 alcohols and aldehydes and their derivatives), but also includes multiple minor VOCs that collectively act as infochemicals, inducing defences in non-damaged plant leaves and neighbouring plants and attracting herbivore enemies. At present, the interspecific variability of the rate of induction and magnitude of wounding-induced emissions and the extent to which plant structural traits and physiological activity alter these emissions are poorly known. Particularly scarce is information on the induced emissions in tropical agricultural plant species, despite their economic importance and large area of cultivation at regional and global scales. We chose five tropical crops with varying photosynthetic activity and leaf structural characteristics-Abelmoschus esculentus, Amaranthus cruentus, Amaranthus hybridus, Solanum aethiopicum, and Telfairia occidentalis-to characterize the kinetics and magnitude of wounding-induced emissions, hypothesizing that the induced emission response is greater and faster in physiologically more active species with greater photosynthetic activity than in less active species. Rapid highly repeatable leaf wounds (12 mm cuts) were generated by a within-leaf-chamber cutting knife. Wounding-induced VOC emissions were measured continuously with a proton-transfer reaction time-of-flight mass spectrometer and gas-chromatography mass spectrometry was used to separate isomers. Twenty-three ion VOCs and twelve terpenoid molecule structures were identified, whereas ubiquitous stress volatiles methanol (on average 40% of total emissions), hexenal (24%), and acetaldehyde (11%) were the main compounds across the species. Emissions of low-weight oxygenated compounds (LOC, 70% of total) and LOX products (29%) were positively correlated across species, but minor VOC components, monoterpenoids and benzenoids, were negatively correlated with LOC and LOX, indicating a reverse relationship between signal specificity and strength. There was a large interspecific variability in the rate of induction and emission magnitude, but the hypothesis of a stronger emission response in physiologically more active species was only partly supported. In addition, the overall emission levels were somewhat lower with different emission blend compared to the data reported for wild species, as well as different shares for the VOCs in the blend. The study demonstrates that wounding-dependent emissions from tropical agricultural crops can significantly contribute to atmospheric volatiles, and these emissions cannot be predicted based on current evidence of wild plant model systems" |
| Keywords: | "Biodiversity Gas Chromatography-Mass Spectrometry Herbivory Photosynthesis Plant Leaves/chemistry/metabolism Plants/anatomy & histology/*chemistry/*metabolism Quantitative Trait, Heritable Volatile Organic Compounds/*chemistry/metabolism Wounds and Injuri;" |
| Notes: | "MedlinePortillo-Estrada, Miguel Okereke, Chikodinaka N Jiang, Yifan Talts, Eero Kaurilind, Eve Niinemets, Ulo eng advanced grant 322603, Sip-Vol+/FP7 Ideas: European Research Council/ Centre of Excellence EcolChange/European Regional Development Fund/ baseline-funded project P190252PKTT/Estonian University of Life Sciences/ baseline research/University of Antwerp/ Switzerland 2021/05/06 Molecules. 2021 Apr 29; 26(9):2602. doi: 10.3390/molecules26092602" |
