Evaluation of some potential target genes and methods for RNAi-mediated pest control of the corn earworm Helicoverpa zea.

In this study, we explored the efficacy of knockdown four genes required for proper nervous system function by RNAi, in the corn earworm Helicoverpa zea (Boddie). Three of these genes encode components of validated insecticide target sites. We synthesized cDNA sequences orthologous to the Drosophila melanogaster genes Para (paralytic), TipE (temperature-induced paralysis locus E), GluCl (glutamate-gated chloride channel), and Notch, and used these fragments to synthesize double-stranded RNAs (dsRNAs).

Conserved Patterns of Sex Chromosome Dosage Compensation in the Lepidoptera (WZ/ZZ): Insights from a Moth Neo-Z Chromosome.

Where previously described, patterns of sex chromosome dosage compensation in the Lepidoptera (moths and butterflies) have several unusual characteristics. Other female-heterogametic (ZW/ZZ) species exhibit female Z-linked expression that is reduced compared with autosomal expression and male Z expression. In the Lepidoptera, however, Z expression typically appears balanced between sexes but overall reduced relative to autosomal expression, that is Z ≈ ZZ < AA.

Phenotypic screen for RNAi effects in the codling moth Cydia pomonella.

RNAi-based technologies have the potential to augment, or replace existing pest management strategies. However, some insect taxa are less susceptible to the induction of the post-transcriptional gene silencing effect than others, such as the Lepidoptera. Here we describe experiments to investigate the induction of RNAi in the codling moth, Cydia pomonella, a major lepidopteran pest of apple, pear, and walnut.

An abundant acyl-CoA (Delta9) desaturase transcript in pheromone glands of the cabbage moth, Mamestra brassicae, encodes a catalytically inactive protein.

The principal sex pheromone component produced by females of the cabbage moth, Mamestra brassicae, is derived from the monounsaturated fatty acid, Z11-16:1, whereas two additional trace components are derived from E11-16:1 and Z9-16:1. This report presents the isolation and analysis of cDNAs encoding pheromone gland-specific acyl-CoA desaturases implicated in the production of these unsaturated fatty acids (UFAs). Comparisons of the encoded amino acid sequences of four cDNA fragments isolated by degenerate PCR from cabbage moth pheromone glands established their orthology with previously characterized noctuid desaturases as follows: MbraLPAQ, belonging to the pheromone gland-specific LPAQ desaturase lineage having Delta11 regioselectivity, MbraKPSE-a and MbraKPSE-b, belonging to the pheromone gland-specific KPSE desaturase lineage having Delta9 regioselectivity and a substrate preference for palmitic acid (16:0) over oleic acid (18:0), and MbraNPVE, belonging to the NPVE desaturase lineage having Delta9 regioselectivity and a substrate preference 18:0>16:0.

cis-3-Hexenal production in tobacco is stimulated by 16-carbon monounsaturated fatty acids.

Transgenic tobacco plants O9 and T16 expressing the yeast acyl-CoA Delta9 desaturase and an insect acyl-CoA Delta11 desaturase, respectively, displayed altered profiles of fatty acids compared to wild-type tobacco plants and marked increases in cis-3-hexenal, a major leaf volatile derived from alpha-linolenic acid (18:3). As expected, O9 and T16 plants had increased levels of the major unsaturated fatty acid products formed by the transgenic desaturases they expressed, viz., palmitoleic acid (16:1(Delta9)) and palmitvaccenic acid (16:1(Delta11)), respectively.

Multiple acyl-CoA desaturase-encoding transcripts in pheromone glands of Helicoverpa assulta, the oriental tobacco budworm.

Seven desaturase cDNAs were isolated from pheromone glands of Helicoverpa assulta, a moth producing a sex pheromone blend with high Z9-16:Ald and low Z11-16:Ald, opposite to what is found in other heliothine moths such as Helicoverpa zea. Six of the seven sequences map onto recently defined lepidopteran desaturase sequence lineages and the other is orthologous to a desaturase sequence previously reported only in H. zea.

Ethanol tolerance in the yeast Saccharomyces cerevisiae is dependent on cellular oleic acid content.

In this investigation, we examined the effects of different unsaturated fatty acid compositions of Saccharomyces cerevisiae on the growth-inhibiting effects of ethanol. The unsaturated fatty acid (UFA) composition of S. cerevisiae is relatively simple, consisting almost exclusively of the mono-UFAs palmitoleic acid (Delta(9)Z-C(16:1)) and oleic acid (Delta(9)Z-C(18:1)), with the former predominating.

Evolution of the integral membrane desaturase gene family in moths and flies.

Lepidopteran insects use sex pheromones derived from fatty acids in their species-specific mate recognition system. Desaturases play a particularly prominent role in the generation of structural diversity in lepidopteran pheromone biosynthesis as a result of the diverse enzymatic properties they have evolved. These enzymes are homologous to the integral membrane desaturases, which play a primary role in cold adaptation in eukaryotic cells.

Developmental regulation of alternative exon usage in the house fly Vssc1 sodium channel gene.

Sequence analysis of cDNA clones amplified by PCR from house fly ( Musca domestica L.) Vssc1 voltage-sensitive sodium channel alpha subunit transcript templates identified 11 putative alternatively spliced exons. Nine of these corresponded to the 7 optional exons (designated a, b, e, f, h, i, and j) and 2 mutually exclusive exons (designated c/d) identified previously in the orthologous para sodium channel alpha subunit genes of Drosophila melanogaster and Drosophila virilis, whereas two segments represented new mutually exclusive exons in Vssc1 (designated k/l) located in a region not previously identified as a site of alternative splicing in para.