Specificity of Herbivore Defense Responses in a Woody Plant, Black Poplar (Populus nigra)

Abstract

The specificity of woody plant defense responses to different attacking herbivores is poorly known. We investigated the responses of black poplar ( Populus nigra ) to leaf feeding by three lepidopteran species ( Lymantria dispar, Laothoe populi and Amata mogadorensis ) and two leaf beetle species ( Phratora vulgatissima and Chrysomela populi ). Of the direct defenses monitored, increases in trypsin protease inhibitor activity and the salicinoid salicin were triggered by herbivore damage, but this was not herbivore-specific. Moreover, the majority of leaf salicinoid content was present constitutively and not induced by herbivory. On the other hand, volatile emission profiles did vary among herbivore species, especially between coleopterans and lepidopterans. Monoterpenes and sesquiterpenes were induced in damaged and adjacent undamaged leaves, while the emission of green leaf volatiles, aromatic and nitrogen-containing compounds (known to attract herbivore enemies) was restricted to damaged leaves. In conclusion, indirect defenses appear to show more specific responses to attacking herbivores than direct defenses in this woody plant. Electronic supplementary material The online version of this article (10.1007/s10886-019-01050-y) contains supplementary material, which is available to authorized users.

Poplar protease inhibitor expression differs in an herbivore specific manner

“…All of these traits can be herbivore species-specific and may allow plants to distinguish among attackers and mount adequate and effective defenses against specific herbivores. In black poplar trees, such herbivore-specific reactions could be shown for signaling molecules [ 14 ], as well as chemical defense traits such as volatile emission [ 14 , 31 , 47 ]. In a recent study by Fabisch et al [ 14 ], total PI activity against trypsin was more strongly induced by beetle feeding than by caterpillar feeding on black poplar leaves.…”

“…In black poplar trees, such herbivore-specific reactions could be shown for signaling molecules [ 14 ], as well as chemical defense traits such as volatile emission [ 14 , 31 , 47 ]. In a recent study by Fabisch et al [ 14 ], total PI activity against trypsin was more strongly induced by beetle feeding than by caterpillar feeding on black poplar leaves. However, to date, we do not know which specific genes are responsible for the observed differences in PI activity and whether or not transcription of PI-encoding genes differs between beetle- and caterpillar-fed leaves.…”

Previous herbivory alerts conspecific gravid sawflies to avoid unsuitable host plants

“…These changes could be mediated by phytohormones (like jasmonic or salicylic acid). Actually, jasmonic acid, not salicylic, was induced in poplar trees after feeding of leaf-chewing herbivores in damaged and adjacent undamaged leaves (Fabisch et al ., 2019). Moreover, defoliation by sawflies is known to modify the N content of the foliage and consequently its nutritive value [i.e.…”

Transcriptomic and Metabolomic Analyses to Unravel Responses of Populus Simonii × P. Nigra to attack by Asian Gypsy moth Lymantria Dispar (Lepidoptera: Lymantriidae)

“…The genes involved in phenylpropanoid metabolism signi cantly overexpressed in previously oviposited S. dulcamara plants by lepidopteran herbivore S. exigua [12]. Moreover, pro les of volatile emission did vary in the indirect defenses of Populus nigra to leaf herbivory by lepidopteran species (Lymantria dispar, Laothoe populi and Amata mogadorensis) and beetles species (Phratora vulgatissima and Chrysomela populi) [27]. The transcriptome and metabolome analyses showed the ROS and calcium in early signaling, and salicylic acid (SA) and jasmonic acid (JA) mediated the defence regulation of Arabidopsis thaliana attacked by Brevicoryne brassicae.…”