Genetic improvements to the sterile insect technique for agricultural pests

The sterile insect technique (SIT) relies on area-wide mass-releases of sterile male pest insects, which mate with their wild counterparts and thereby cause a drop in the wild population. In order to improve SIT efficacy or to avoid potential negative effects of such releases, strains of insects have been developed by genetic means. Methods of strain improvement fall into two categories: those generated by classical genetics and those through transgenesis. Here, we describe development and successes of agriculturally important pest insect strains developed through the former, and how transgenic technology is offering a broad spectrum of potential improvements to SIT in a wider range of insects. Also discussed are future prospects and non-technical challenges faced by transgenic technology. The need for environment-friendly pest control methods in agriculture has never been more pressing. SIT and related technologies offer a solution with proven effectiveness

RNA interference in Lepidoptera: an overview of successful and unsuccessful studies and implications for experimental design

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Unusually Long Palindromes Are Abundant in Mitochondrial Control Regions of Insects and Nematodes

BACKGROUND: Palindromes are known to be involved in a variety of biological processes. In the present investigation we carried out a comprehensive analysis of palindromes in the mitochondrial control regions (CRs) of several animal groups to study their frequency, distribution and architecture to gain insights into the origin of replication of mtDNA. METHODOLOGY/PRINCIPAL FINDINGS: Many species of Arthropoda, Nematoda, Mollusca and Annelida harbor palindromes and inverted repeats (IRs) in their CRs. Lower animals like cnidarians and higher animal groups like chordates are almost devoid of palindromes and IRs. The study revealed that palindrome occurrence is positively correlated with the AT content of CRs, and that IRs are likely to give rise to longer palindromes. CONCLUSIONS/SIGNIFICANCE: The present study attempts to explain possible reasons and gives in silico evidence for absence of palindromes and IRs from CR of vertebrate mtDNA and acquisition and retention of the same in insects. Study of CRs of different animal phyla uncovered unique architecture of this locus, be it high abundance of long palindromes and IRs in CRs of Insecta and Nematoda, or short IRs of 10–20 nucleotides with a spacer region of 12–14 bases in subphylum Chelicerata, or nearly complete of absence of any long palindromes and IRs in Vertebrata, Cnidaria and Echinodermata

De Novo assembly and transcriptome analysis of the mediterranean fruit fly ceratitis capitata early embryos

The agricultural pest Ceratitis capitata, also known as the Mediterranean fruit fly or Medfly, belongs to the Tephritidae family, which includes a large number of other damaging pest species. The Medfly has been the first non-drosophilid fly species which has been genetically transformed paving the way for designing geneticbased pest control strategies. Furthermore, it is an experimentally tractable model, in which transient and transgene-mediated RNAi have been successfully used. We applied Illumina sequencing to total RNA preparations of 8-10 hours old embryos of C. capitata, This developmental window corresponds to the blastoderm cellularization stage. In summary, we assembled 42,614 transcripts which cluster in 26,319 unique transcripts of which 11,045 correspond to protein coding genes; we identified several hundreds of long ncRNAs; we found an enrichment of transcripts encoding RNA binding proteins among the highly expressed transcripts, such as CcTRA-2, known to be necessary to establish and, most likely, to maintain female sex of C. capitata. Our study is the first de novo assembly performed for Ceratitis capitata based on Illumina NGS technology during embryogenesis and it adds novel data to the previously published C. capitata EST databases. We expect that it will be useful for a variety of applications such as gene cloning and phylogenetic analyses, as well as to advance genetic research and biotechnological applications in the Medfly and other related Tephritidae