Camacho-Coronel Xicotencatl, Molina-Torres Jorge, Heil Martin
Laboratorio de Ecología de Plantas, CINVESTAV-Irapuato, Departamento de Ingeniería Genética, Irapuato, México.
Laboratorio de Fitobioquímica, CINVESTAV-Irapuato, Departamento de Biotecnología y Bioquímica, Irapuato, México.
Front Plant Sci. 2020 Feb 25;11:121. doi: 10.3389/fpls.2020.00121. eCollection 2020.
Numerous plant-derived volatile organic compounds (VOCs) induce the expression of resistance-related genes and thereby cause an "associational resistance" in neighbouring plants. However, VOCs can also be sequestered by plant cuticular waxes. In case that they maintain their biological activity, such sequestered VOCs could generate a "passive" associational resistance that is independent of any gene expression in the receiver. As a proof of concept, we used major components of the cuticular wax layers of the tree, , and conidia of a fungal pathogen that has not been reported to infect . Wax layers were re-constituted on glass slides and exposed to each of 20 pure VOCs for 1 d and then to ambient air for 1 d or 15 d. Gas chromatography-mass spectrometry (GC-MS) analyses showed that all 20 VOCs were sequestered by the re-constituted wax layers. Exposure to 18 of the VOCs significantly inhibited the germination of conidia on these wax layers after 1 day of exposure to ambient air. Four of the VOCs: 4-heptenol, farnesene, limonene, and 2-decenal, inhibited germination rates to less than 25% of the controls. After 15 d, all VOCs were still detectable, although at strongly reduced concentrations, and no significant inhibition of conidial germination could be detected anymore. Exogenous VOCs can be sequestered by the components of plant cuticular waxes and maintain their biological activity, at least over a certain time span: an effect that could generate a transient "passive associational resistance" to pathogens.
许多植物源挥发性有机化合物（VOCs）可诱导抗性相关基因的表达，从而在邻近植物中产生“关联抗性”。然而，VOCs也可被植物表皮蜡质封存。如果它们保持其生物活性，这种被封存的VOCs可能会产生一种“被动”关联抗性，该抗性独立于受体中的任何基因表达。作为概念验证，我们使用了树木表皮蜡层的主要成分以及一种尚未报道可感染该树木的真菌病原体的分生孢子。将蜡层重新构建在载玻片上，使其暴露于20种纯VOCs中的每一种1天，然后暴露于环境空气中1天或15天。气相色谱 - 质谱（GC - MS）分析表明，所有20种VOCs均被重新构建的蜡层封存。在暴露于环境空气1天后，暴露于其中18种VOCs显著抑制了这些蜡层上分生孢子的萌发。其中4种VOCs：4 - 庚烯醇、法尼烯、柠檬烯和2 - 癸烯醛，将萌发率抑制至对照的25%以下。15天后，所有VOCs仍可检测到，尽管浓度大幅降低，并且再也检测不到对分生孢子萌发的显著抑制。外源VOCs可被植物表皮蜡质成分封存并保持其生物活性，至少在一定时间跨度内如此：这种效应可能会对病原体产生短暂的“被动关联抗性”。
