Targeting the diuretic hormone receptor to control the cotton leafworm, Spodoptera littoralis

Abstract

The cotton leafworm, Spodoptera littoralis Boisduval (Lepidoptera: Noctuidae), is one of the most devastating pests of crops worldwide. Several types of treatments have been used against this pest, but many of them failed because of the rapid development of genetic resistance in the different insect populations. G protein coupled receptors have vital functions in most organisms, including insects; thus, they are appealing targets for species-specific pest control strategies. Among the insect G protein coupled receptors, the diuretic hormone receptors have several key roles in development and metabolism, but their importance in vivo and their potential role as targets of novel pest control strategies are largely unexplored. With the goal of using DHR genes as targets to control S. littoralis, we cloned a corticotropin-releasing factor-like binding receptor in this species and expressed the corresponding dsRNA in tobacco plants to knock down the receptor activity in vivo through RNA interference. We also expressed the receptor in mammalian cells to study its signaling pathways. The results indicate that this diuretic hormone receptor gene has vital roles in S. littoralis and represents an excellent molecular target to protect agriculturally-important plants from this pest.

Molecular characterization and expression profiles of neuropeptide precursors in the migratory locust

“…Furthermore, we found several solitarious-dependent neuropeptide genes (Lom-MS, Lom-ITP, Lom-EH, Lom-DH-Calc and Lom-AST-CC). As suggested by earlier studies, these genes participate in endocrine regulation on either metabolism or ecdysis behavior (Apone et al, 2014;Arakane et al, 2008;Zandawala, 2012). The coincident expression patterns these genes in the first-and second-stadium solitarious locusts may imply their coordinative regulation on phase-related growth and development at early nymph stage, as affected by their parent phase states.…”

G protein coupled receptors as targets for next generation pesticides

“…Although there is very little information on the physiology and behaviour of D. suzukii, if it is assumed that its DH-receptors are involved in similar processes to those in D. melanogaster, they offer prospective targets for novel pesticides. Such insecticidal potential was demonstrated by knocking down the CRF-like DH-receptor in Spodoptera littoralis larvae through expression of the corresponding dsRNA in tobacco plants (Apone et al, 2014). A similar knockdown strategy against DH 44 or the corresponding receptors could be used to determine any detrimental effects in D. suzukii.…”

Biosynthesis of 8-hydroxyquinoline-2-carboxylic acid, an iron chelator from the gut of the lepidopteran Spodoptera littoralis

“…2). 17,19 Thus, the growth of strongly Fe-dependent bacteria should be reduced or inhibited, as already shown by in vitro experiments 23 using 8-HQA at typical gut concentrations (ca. The biosynthesis proceeds via kynurenine and 3-hydoxykynurenin, as the production is effectively blocked by the KMO-inhibitor mNBA.…”

“…2) and in O. cerasi, but not in M. sexta, A. urticae, Malacosoma sp., P. xylostella and Y. evonymellus. 17 Pupae and adults of S. littoralis do not contain 8-HQA, but in pupae an accumulation 3-hydroxykynurenin (ca. 23 Different compartments of S. littoralis were tested for the presence of 8-HQA.…”

“…16 As this compound was present in high concentrations (up to 5 mmol), 17 we also analyzed closely related species for the presence of 8-HQA (Table S1 †). Our data suggest a conversion of Trp via 3-hydroxykynurenine and ring closure to give 8-HQA.…”