Glutathione S-transferases in the adaptation to plant secondary metabolites in theMyzus persicae aphid

Abstract

Glutathione S-transferases (GST) in insects play an important role in the detoxification of many substances including allelochemicals from plants. Induction of GST activity in Myzus persicae in response to secondary metabolites from Brassica plants was determined using different host plant species and confirmed using artificial diet with pure allelochemicals added. The 2,4-dinitro-1-iodobenzene (DNIB) was found to be a useful substrate for identifying particular GSTs in insects. GSTs from M. persicae were purified using different affinity chromatography columns and related kinetic parameters were calculated. GST isoenzymes were characterised using electrophoretic methods. Although SDS-PAGE results indicated similarity among the purified enzymes from each affinity column, biochemical studies indicated significant differences in kinetic parameters. Finally, the GST pattern of M. persicae was discussed in terms of insect adaptation to the presence of plant secondary substances such as the glucosinolates and the isothiocyanates, from Brassicaceae host plants.

Species-Specific Glucosylation of DIMBOA in Larvae of the Rice Armyworm

“…2. Five distinct peaks (1)(2)(3)(4)(5) were observed in the frass of M. separata larvae fed on the diet containing DIMBOA, whereas they were absent in the frass of M. separata larvae that had been fed without DIMBOA. By comparing the chromatographic behavior in the HPLC analyses and ESI mass spectra with those of authentic compounds, compounds 2 (t R 21.0 min) and 5 (t R 31.7 min) were identified as DIMBOA (m=z 164, ½M À H À CH 2 O 2 À ) and MBOA (m=z 164, ½M À H À ), respectively (Fig.…”

“…4) Elucidation of the detoxification mechanisms in insects is very important to understand the interactions between plants and herbivores, because tolerance to potentially poisonous plant secondary metabolites is crucial to the determination of the host range of a species. We report in this study the detoxification mechanism of the rice armyworm, Mythimna separata (Lepidoptera: Noctuidae), which feeds on graminaceous plants containing benzoxazinoids (Bxs).…”

Myzus persicaeSulzer aphid contains oxylipins that originate from phloem sap

“…It can be concluded that both compounds even at high concentration (150 nM) do not significantly increase mortality compared to the reference. Aphids are known as formidable pests capable of infesting various host plants (Blackman & Eastop 1994) and of resisting to herbicides (Lan et al 2005), parasites (Oliver et al 2003) and secondary metabolites (Francis et al 2005).…”

Repellent and Fumigant Activities of <i>Tanacetum nubigenum</i> Wallich. ex DC Essential Oils against <i>Tribolium castaneum</i> (Herbst) (Coleoptera: Tenebrionidae)

“…Plant products inter into the tissue and organ of target insects and affect the activity of various detoxifying enzymes 23 . Francis et al 24 investigated the insecticidal mechanisms by determining the activity of detoxifyning enzymes after biological insecticides have entered the target insects. There are two enzymes i.e.…”