Specific Polyphenols and Tannins are Associated with Defense Against Insect Herbivores in the Tropical Oak Quercus oleoides

Abstract

The role of plant polyphenols as defenses against insect herbivores is controversial. We combined correlative field studies across three geographic regions (Northern Mexico, Southern Mexico, and Costa Rica) with induction experiments under controlled conditions to search for candidate compounds that might play a defensive role in the foliage of the tropical oak, Quercus oleoides. We quantified leaf damage caused by four herbivore guilds (chewers, skeletonizers, leaf miners, and gall forming insects) and analyzed the content of 18 polyphenols (including hydrolyzable tannins, flavan-3-ols, and flavonol glycosides) in the same set of leaves using high performance liquid chromatography and mass spectrometry. Foliar damage ranged from two to eight percent per region, and nearly 90% of all the damage was caused by chewing herbivores. Damage due to chewing herbivores was positively correlated with acutissimin B, catechin, and catechin dimer, and damage by mining herbivores was positively correlated with mongolinin A. By contrast, gall presence was negatively correlated with vescalagin and acutissimin B. By using redundancy analysis, we searched for the combinations of polyphenols that were associated to natural herbivory: the combination of mongolinin A and acutissimin B had the highest association to herbivory. In a common garden experiment with oak saplings, artificial damage increased the content of acutissimin B, mongolinin A, and vescalagin, whereas the content of catechin decreased. Specific polyphenols, either individually or in combination, rather than total polyphenols, were associated with standing leaf damage in this tropical oak. Future studies aimed at understanding the ecological role of polyphenols can use similar correlative studies to identify candidate compounds that could be used individually and in biologically meaningful combinations in tests with herbivores and pathogens.

Phenolic Compositions and Antioxidant Properties in Bark, Flower, Inner Skin, Kernel and Leaf Extracts of Castanea crenata Sieb. et Zucc

“…Total phenolic and flavonoid contents of inner skins were also greater than previous results reported by Lee et al [24] that C. crenata possessed only 5.33 mg GAE/g in total phenolic contents, and 0.12 mg QE/g in total flavonoid contents. Phenolic acids and tannins are often stored in plant seeds to protect from pathogen and insect attack [26]; in agreement, inner skins were found to obtain high contents of these compounds in this study.…”

Distribution and characterisation of phenolic compounds in Macaranga pruinosa and associated soils in a tropical peat swamp forest

“…anthocyanins) and protection against ultraviolet (UV) light (e.g. phenylpropanoids) (Lattanzio et al 2012, Constabel et al 2014, Moctezuma et al 2014. The composition and abundance of phenolic compounds within plants vary seasonally and spatially, depending on environmental conditions and different plant structures, for example they are typically higher in mature than immature leaves (Lattanzio et al 2012).…”

Comparative chemistry and biological properties of the solid residues from hydrodistillation of Spanish populations of <em>Rosmarinus officinalis</em> L.

“…The involvement of plant phenolics in the plant mechanism against insects and its role on the feeding behavior of herbivores is well known through the ages, and has been recently reviewed (Lattanzio et al, 2012). Specific polyphenols, either individually or in combination, have been associated with defense against insect herbivores in Quercus oleoides (Moctezuma et al, 2014). Fornoff and Gross (2014) reported the increase in polyphenols as one of the induced resistance and defensive traits of Myriophyllum spicatum to prevent herbivore damage.…”