Volatile-organic compound changes in rose twigs consequent to infection with rose powdery mildew

Abstract

The chemical mechanisms involved in indirect plant-mediated interactions between insects and phytopathogenic fungi on the host plant are poorly understood. Fungus-induced changes in the volatile organic compound (VOC) contents of plants need to be elucidated to address this. Here, changes in VOCs in rose (Rosa chinensis Jacq.) leaves infected with rose powdery mildew (Podosphaera pannosa [Wallr.: Fr.] de Bary) were studied. VOCs were collected from undamaged live leaves of healthy and infected intact rose plants by dynamic headspace adsorption and identified by GC-MS. VOCs were extracted using n-hexane, and 38 chemicals were found to be produced by P. pannosa. A total of 71 VOCs not produced by P. pannosa were produced to different degrees by infected and healthy plants, and 18 of these were produced only by infected plants. Principal component analysis of chromatographic data gave VOC profiles distinguishing between infected and healthy plants. Hexadecanol, octadecanol, tetradecanol, n-butyl hexadecanoate, and n-butyl stearate dominated the VOCs produced by infected plants. These chemicals can be used as markers for detecting mildew-infected rose plants even 4-7 d after infection before symptoms appear. Clear temporal changes in the concentrations of these five chemicals were found. The results improve our understanding of the chemical mechanisms involved in interactions between insects and phytopathogenic fungi.

Investigation of Food Additive Potential of the Rosa damascena Mill. (Isparta Rose): Vinegar with Probiotic Addition

“…Over the storage period, rose vinegar supplemented with probiotics increased the levels of 1-Dodecene and n-Dodecene, aligning with the ndings of [46]. Similarly, the levels of 1-hexadecanol, a volatile organic compound found in roses [47], and 1-Tetradecanol, associated with a fruity and coconut-like aroma [48], along with alcoholderived compounds such as heptadecanol, hexadecanol, and n-tetradecane, increased at the end of the storage period. This observation suggests that probiotic strains contribute to the fermentation process during storage, resulting in higher concentrations of volatile alcohol compounds.…”

Volatile Organic Compounds from Cassava Plants Confer Resistance to the Whitefly Aleurothrixus aepim (Goeldi, 1886)

“…The latter emits volatile compounds such as phytane, heneicosane, and heptadecane, similar to healthy Rosa chinensis Jacq. plants, which easily contract powdery mildew [ 62 ]. Furthermore, the heneicosane and other long-chain alkanes found in this cultivar are attractive to Callosobruchus maculatus (Fabricius) (Coleoptera: Bruchidae), a critical seed pest of Lathyrus sativus L. [ 63 ], which can be connected to the susceptibility of this cultivar to whiteflies.…”

A hymenopteran odorant alerts flies to bury eggs

“…For example, 1-octadecanol is a component in the pheromone blend secreted from the male hairpencil glands of various male lepidopterans to attract females (Bober & Rafaeli, 2010;Teal & Tumlinson, 1989). However, 1-octadecanol has been reported to have repulsive effects on other insects: aphids (Rhopalosiphum padi) avoid leaves coated with Trichoderma fungi, which produce 1-octadecanol (Ganassi et al, 2016), and the beet armyworm, Spodoptera exigua, avoids ovipositing on roses infected with the powdery mildew Podosphaera pannosa (Fa-zhong Yang et al, 2013), due to increased plant production of volatiles like 1-octadecanol (Fazhong Yang et al, 2019). In our system, flies do not seem deterred from ovipositing on food substrates with ant odors or 1-octadecanol, they just lay their eggs deeper into the substrate.…”