SEQUENCE ANALYSIS OF INSECTICIDE RESISTANCE AND DETOXIFICATION RELATED GENES IN Spodoptera littoralis(LEPIDOPTERA: NOCTUIDAE)

Abstract

The Egyptian cotton leaf worm, Spodoptera littoralis (Boisd. ) is a well-known asone of the most destructive agricultural lepidopterous pests. It is a true generalistspecies with a promiscuous feeding strategy which enables it to attack numerouseconomically important crops all year round including vegetables, ornamentalplants, and cotton. Recently, chemical control has been commonly used to suppresspopulations of S. littoralis; however, a very large number of insecticides have ledtothe emergence ofresistance. An extensive use of insecticides also has other sideeffects, including the elimination of non-targeted organisms, environmentaldamage and harm to human health. Genome-wide high-throughput technologieshelp developing resistance management strategies, especially identifying geneticmechanisms of resistance. The aim of the present study was to produce a de novotranscriptome for S. littoralis as a resource for current and future studies of thispest species by using next-generation sequencing. This resource was then used as areference for identifying genes by encoding the target sites of insecticides currentlyin use for Egyptian cotton leaf worm control. To achieve this, a cDNA library wassequenced using 454 FLX Titanium Sequencing on the Roche platform whichrevealed good coverage of genes encoding insecticide target sites anddetoxification enzymes using a manual annotation. Annotations of assembledsequences were carried out by BLASTx against NCBI non-redundant proteinsequence databases using the software Blast2GO. The genesencodingenzymesinvolvedin insecticide detoxification such as Acetylcholinesterase,Cytochrome p450, Glutathione S-transferase were characterized. Furthermore, aphylogenetic analyses based on three protein sequences were generated in order togive evolutionary insights into insecticide resistance gene families of S. littoralis.

Population variation and polymorphism of the Cotton Pink Bollworm Pectinophora gossypiella (Saunders) (Lepidoptera: Gelechiidae) using Inter Simple Sequence Repeats (ISSRs) as molecular markers

“…Therefore monitoring the effects of these processes on population variation at the molecular scale are urgently needed (Lega etal., 2002). Study of nucleotide diversity is known to assess genetic variation within and among insect populations from different environments across cultivated areas (Vijayan et al, 2006) and build brief relationship through pairwise genetic distance and matrix to show dissimilarity between samples and to draw a phylogeny tree that can created from gel page of electrophoresis bands and lane of different samples or directly from the alignment of multiple sequences (Guz and Dağeri 2017). In this study within population sampling exploited to focus on genetic differentiation among P. gossypiella few populations at a de nite scale, and to investigate the nature genetic variations in the three-governorate population of P. gossypiella that attack cotton crops in closely related geographical areas of Egyptian governorates without insecticide exposure through PCR-ISSR which considered the molecular procedure of ecological genetic diversity pro le produces acquired in the same species and population level to show the environmental differences between sites.…”