Glucosinolates and other metabolites in the leaves of Arabidopsis thaliana from natural populations and their effects on a generalist and a specialist herbivore

Abstract

Because many secondary metabolites in plants act as defense against herbivores it has been postulated that these compounds have evolved under selective pressure by insect herbivores. One explanation for the within-species variation in metabolite patterns in a particular species is that different populations are under selection by different herbivores. We tested this hypothesis, using Arabidopsis thaliana plants that originated from dune and inland areas. We analyzed Arabidopsis thaliana leaves using NMR spectroscopy and multivariate data analysis. Major differences in chemical composition were found in water-methanol fractions and were due to higher concentrations of sinigrin and fumaric acid in dune plants. Inland plants showed lower levels of glucose. Quantitative analysis of glucosinolates was performed with HPLC. Individual plants and populations demonstrated differences in glucosinolate composition and concentration. In growth chamber experiments, the generalist herbivore, Spodoptera exigua grew significantly better on the inland plants, while the specialist herbivore Plutella xylostella performed equally well on plants of both origins. Aliphatic glucosinolate as well as total glucosinolate concentrations negatively correlated with larval mass of Spodoptera exigua. No significant correlations, however, were found between larval mass of Plutella xylostella and glucosinolates in the leaves. A specialist and a generalist herbivore were responding differently to plant secondary chemistry, as was also found in several other studies. This is an important indication that differences in glucosinolate concentrations among populations may result from differential selection by different guilds of herbivores.

Effects of glucosinolates on a generalist and specialist leaf-chewing herbivore and an associated parasitoid

“…Alternatively, higher GLS concentrations might induce enhanced NSP biosynthesis 271 that incurs higher energetic costs for the insect. Our finding of a negative correlation between 272 GLS and herbivore performance are in agreement with other studies using S. exigua (Arany et al, 2008;Gigolashvili et al, 2007;Müller et al, 2010) and P. rapae (Agrawal and Kurashige,274 2003). However, opposite to our findings, two other studies did not find major changes in 275 larval development of P. rapae due to increased aliphatic GLS concentrations (Gols et al,276 2008b; Müller et al, 2010).…”

Impact of hydroxylated and non-hydroxylated aliphatic glucosinolates in Arabidopsis thaliana crosses on plant resistance against a generalist and a specialist herbivore

“…In general, generalist herbivores are more negatively affected by GSs. Typically they are influenced by high levels of these secondary compounds with a poor larval performance (Kroymann et al 2003;Arany et al 2008). In the present study, the generalist S. exigua performed equally well on GxS-MSOP lines with general low GS levels as well as on GxS-OHP lines with general high GS levels.…”

A Ni hyperaccumulator and a congeneric non-accumulator reveal equally effective defenses against herbivory

“…It might be that Ni is not acting as an inorganic defense in A. pintodasilvae and that the same components which have antifeeding effect in A. simplex are also present in A. pintodasilvae. For example, glucosinolates that are abundant in the Brassicaceae have documented deterrence effects in generalist herbivores (Arany et al, 2008;Lankau, 2007;Noret et al, 2005;Rask et al, 2000). An alternative scenario would be that Ni defends A. pintodasilvae against herbivores, but that glucosinolates or other organic compounds in A. simplex leaves could counter balance the low concentrations of Ni in this plant species.…”