Physical and Chemical Traits of Grape Varieties Influence Drosophila suzukii Preferences and Performance.

Lisa Weißinger,Caroline Müller,Hanns-Heinz Kassemeyer,Michael Breuer,Evi Bieler,Katja Arand

doi:10.3389/fpls.2021.664636

Abstract

The cuticle-covered surface forms the interface between plant parts, including fruits, and their environment. The physical and chemical properties of fruit surfaces profoundly influence plant-frugivore interactions by shaping the susceptibility and suitability of the host for the attacker. Grapevine (Vitis vinifera, Vitaceae) serves as one of the various host plants of the spotted wing drosophila, Drosophila suzukii Matsumura (Diptera: Drosophilidae), which is invasive in several parts of the world and can cause major crop losses. The susceptibility of wine towards this pest species differs widely among varieties. The objective of our study was to identify physical and chemical traits of the berry surface that may explain the differences in susceptibility of five grape varieties to D. suzukii. Both preferences of adult D. suzukii and offspring performance on intact versus dewaxed (epicuticular wax layer mechanically removed) grape berries were investigated in dual-choice assays. Moreover, the morphology and chemical composition of cuticular waxes and cutin of the different varieties were analyzed. Bioassays revealed that the epicuticular wax layer of most tested grape varieties influenced the preference behavior of adult flies; even less susceptible varieties became more susceptible after removal of these waxes. In contrast, neither offspring performance nor berry skin firmness were affected by the epicuticular wax layer. The wax morphology and the composition of both epi- and intracuticular waxes differed pronouncedly, especially between more and less susceptible varieties, while cutin was dominated by ω-OH-9/10-epoxy-C18 acid and the amount was comparable among varieties within sampling time. Our results highlight the underestimated role of the epicuticular surface and cuticle integrity in grape susceptibility to D. suzukii.

Highlights

Plant-insect interactions have evolved over hundreds of millions of years and are of crucial importance for the earth’s ecosystems (Schoonhoven et al, 2005; Whitney and Federle, 2013)
Dual-choice assays revealed that D. suzukii preferences were clearly affected by berry surfaces for almost all tested grape varieties (Figure 2 and Table 2)
Previous field observations indicated that grape berries of rather less accepted varieties, even if not obviously pre-damaged, can still be attacked sporadically by D. suzukii (Weißinger et al, 2019a)

Summary

Introduction

Plant-insect interactions have evolved over hundreds of millions of years and are of crucial importance for the earth’s ecosystems (Schoonhoven et al, 2005; Whitney and Federle, 2013). These complex interactions can be mutualistic, commensalistic or antagonistic (Schoonhoven et al, 2005; Calatayud et al, 2018). The latter is of particular relevance for agricultural crop production, because insect pests can cause massive degradation and crop loss. Varietyspecific differences in fruit susceptibility to antagonists are of particular importance in viticulture, where distinct physical and chemical properties determine the sensory characteristics and quality of the wine (Vitis vinifera, Vitaceae) (Manso-Martínez et al, 2020; Tonina et al, 2020)

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Conclusion