title: EMS mutagenesis in the pea aphid Acyrthosiphon pisum.
abstract: In aphids, clonal individuals can show distinct morphologic traits in response to environmental cues. Such phenotypic plasticity cannot be studied with classical genetic model organisms such as Caenorhabditis elegans or Drosophila melanogaster. The genetic basis of this biological process remain unknown, as mutations affecting this process are not available in aphids. Here, we describe a protocol to treat third-stage larvae with an alkylating mutagen, ethyl methanesulfonate (EMS), to generate random mutations within the Acyrthosiphon pisum genome. We found that even low concentrations of EMS were toxic for two genotypes of A. pisum. Mutagenesis efficiency was nevertheless assessed by estimating the occurrence of mutational events on the X chromosome. Indeed, any lethal mutation on the X-chromosome would kill males that are haploid on the X so that we used the proportion of males as an estimation of mutagenesis efficacy. We could assess a putative mutation rate of 0.4 per X-chromosome at 10 mM of EMS. We then applied this protocol to perform a small-scale mutagenesis on parthenogenetic individuals, which were screened for defects in their ability to produce sexual individuals in response to photoperiod shortening. We found one mutant line showing a reproducible altered photoperiodic response with a reduced production of males and the appearance of aberrant winged males (wing atrophy, alteration of legs morphology). This mutation appeared to be stable because it could be transmitted over several generations of parthenogenetic individuals. To our knowledge, this study represents the first example of an EMS-generated aphid mutant.
authors: UMR 1349 IGEPP (Institute of Genetics Environment and Plant Protection), Domaine de la Motte, 35657 Le Rheu Cedex, France.
authors: Denis
authors: D
authors: Tagu
authors: Gaël
authors: G
authors: Le Trionnaire
authors: Sylvie
authors: S
authors: Tanguy
authors: Jean-Pierre
authors: JP
authors: Gauthier
authors: Jean-René
authors: JR
authors: Huynh
mesh_terms: D000818:Animals; D001042:Aphids / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development; D005020:Ethyl Methanesulfonate / Q000633:toxicity*; D005260:Female; D049750:Genome, Insect; D005838:Genotype; D007814:Larva / Q000187:drug effects; D008297:Male; D016296:Mutagenesis; D014921:Wings, Animal / Q000002:abnormalities; D014960:X Chromosome / Q000187:drug effects
chemical_list: D005020:Ethyl Methanesulfonate
keywords: EMS; X-linked mutation; mutagenesis; pea aphid