scholarly journals Evidence that the E4 and FE4 esterase genes responsible for insecticide resistance in the aphid Myzus persicae (Sulzer) are part of a gene family

1998 ◽  
Vol 330 (1) ◽  
pp. 169-173 ◽  
Author(s):  
M. Linda FIELD ◽  
L. Alan DEVONSHIRE
Keyword(s):  
Insecticide Resistance ◽  
Gene Family ◽  
Myzus Persicae ◽  
Cpg Island ◽  
Gene Families ◽  
Duplication Event ◽  
Potato Aphid ◽  
Insecticide Exposure ◽  
Genes Encoding ◽  
Multiple Copies

The amplification of genes encoding the esterases E4 and FE4 is a widespread mechanism of insecticide resistance in the peach-potato aphid, Myzus persicae (Sulzer). We present evidence that in susceptible aphids the two genes are adjacent to each other in a head-to-tail arrangement with E4 upstream of FE4 and with approx. 19 kb of intervening sequence. There are also at least two other closely related sequences which might come from other members of an esterase gene family, in line with reports of other insect gene families encoding detoxifying enzymes. The close identity between E4 and FE4 genes indicates a recent duplication and divergence. The subsequent amplifications giving multiple copies of either E4 or FE4 must have involved two separate events, each probably occurring once and then being selected by insecticide exposure and spread by migration. The cloning of sequences upstream of the FE4 gene suggest, by comparison with E4, that the two genes are regulated in different ways. FE4 has sequences corresponding to a conventional promoter (TATA box and CAP site) that are not present in E4; on the other hand, FE4 lacks the CpG island present 5ʹ of E4 genes that may control expression through changes in DNA methylation. The differences are likely to have occurred by the duplication event that gave rise to E4 and FE4 leading to different 5ʹ sequences.

scholarly journals The properties of a carboxylesterase from the peach-potato aphid, Myzus persicae (Sulz.), and its role in conferring insecticide resistance

1977 ◽  
Vol 167 (3) ◽  
pp. 675-683 ◽  
Author(s):  
Alan L. Devonshire
Keyword(s):  
Insecticide Resistance ◽  
Myzus Persicae ◽  
Order Rate Constant ◽  
Preliminary Evidence ◽  
Exchange Chromatography ◽  
Potato Aphid ◽  
First Order ◽  
Different Strains ◽  
Hydrolysis Of ◽  
Peach Potato Aphid

Carboxylesterases from different strains of Myzus persicae were examined to try to understand their contribution to insecticide resistance. Preliminary evidence that they are involved comes from the good correlation between the degree of resistance and the carboxylesterase and paraoxon-degrading activity in aphid homogenates. Furthermore the carboxylesterase associated with resistance could not be separated from the insecticide-degrading enzyme by electrophoresis or ion-exchange chromatography. Homogenates of resistant aphids hydrolysed paraoxon 60 times faster than did those of susceptible aphids, yet the purified enzymes from both sources had identical catalytic-centre activities towards this substrate and also towards naphth-1-yl acetate, the latter being hydrolysed by both 2×106 times faster than paraoxon. These observations provide evidence that the enzyme from both sources is identical, and that one enzyme hydrolyses both substrates. This was confirmed by relating the rate of paraoxon hydrolysis to the rate at which paraoxon-inhibited carboxylesterase re-activated. Both had the same first-order rate constant (0.01min−1), showing clearly that the hydrolysis of both substrates is brought about by the same enzyme. Its Km for naphth-1-yl acetate was 0.131mm, and for paraoxon 75pm. The latter very small value could not be measured directly, but was calculated from substrate-competition studies coupled with measurements of re-activation of the diethyl phosphorylated enzyme. Since the purified enzymes from resistant and susceptible aphids had the same catalytic-centre activity, the 60-fold difference between strains must be caused by different amounts of the same enzyme resulting from mutations of the regulator gene(s) rather than of the structural gene.

Transgenic tobacco expressing an Arisaema heterophyllum agglutinin gene displays enhanced resistance to aphids

2004 ◽  
Vol 84 (3) ◽  
pp. 785-790 ◽  
Author(s):  
Jianhong Yao, Xiuyun Zhao ◽  
Huaxiong Qi, Bingliang Wan ◽  
Fei Chen, Xiaofen Sun ◽  
Shanqian Yu ◽  
Kexuan Tang
Keyword(s):  
Transgenic Plants ◽  
Transgenic Tobacco ◽  
Myzus Persicae ◽  
Transgenic Tobacco Plants ◽  
Insect Bioassay ◽  
Tobacco Plants ◽  
Potato Aphid ◽  
Enhanced Resistance ◽  
Multiple Copies ◽  
Peach Potato Aphid

Tobacco leaf discs were transformed with a plasmid, pBIAHA, containing the selectable marker neomycin phosphotransferase gene (nptII) and an Arisaema heterophyllum agglutinin gene (aha) via Agrobacterium tumefaciens-mediated transformation. Thirty-two independent transgenic tobacco plants were regenerated. PCR and Southern blot analyses confirmed that multiple copies of the aha gene had integrated into the plant genome. Northern blot analysis revealed that the aha gene was expressed at various levels in the transgenic plants. Insect bioassay test showed that transgenic plants expressing multiple copies of the aha gene reduced the rate of population increase of the peach potato aphid (Myzus persicae Sulzer). This is the first report that transgenic tobacco plants expressing the aha gene display enhanced resistance to aphids. Key words: Insect bioassay, Arisaema heterophyllum agglutinin, transformation, transgenic tobacco, peach potato aphid (Myzus persicae Sulzer)

Incidence of insecticide resistance alleles in sexually-reproducing populations of the peach–potato aphid Myzus persicae (Hemiptera: Aphididae) from southern France

2003 ◽  
Vol 93 (4) ◽  
pp. 289-297 ◽  
Author(s):  
T. Guillemaud ◽  
A. Brun ◽  
N. Anthony ◽  
M.H. Sauge ◽  
R. Boll ◽  
...  
Keyword(s):  
Insecticide Resistance ◽  
Myzus Persicae ◽  
Resistance Mechanisms ◽  
Resistance Mutations ◽  
Potato Aphid ◽  
Southern France ◽  
Chemical Treatments ◽  
Before And After ◽  
Almost All ◽  
Peach Potato Aphid

AbstractIntensive chemical treatments have led to the development of a number of insecticide resistance mechanisms in the peach–potato aphid Myzus persicae (Sulzer). Some of these mechanisms are known to be associated with negative pleiotropic effects (resistance costs). Molecular and biochemical methods were used to determine the genotypes or phenotypes associated with four insecticide resistance mechanisms in single aphids from sexually-reproducing populations in southern France. The mechanisms considered were E4 and FE4 carboxylesterase overproduction, modified acetycholinesterase, and kdr and rdl resistance-associated mutations. A new method for determining individual kdr genotypes is presented. Almost all resistant individuals overproduced FE4 carboxylesterase, whereas modified acetylcholinesterase was rare. Both the kdr and rdl resistance mutations were present at high frequencies in French sexually-reproducing populations. The frequencies of insecticide resistance genes were compared before and after sexual reproduction in one peach orchard at Avignon to evaluate the potential impact of selection on the persistence of resistance alleles in the over-wintering phase. The frequencies of the kdr and rdl mutations varied significantly between autumn and spring sampling periods. The frequency of the kdr mutation increased, probably due to pyrethroid treatments at the end of the winter. Conversely, the frequency of the rdl mutation decreased significantly during winter, probably because of a fitness cost associated with this mutation.

Variability among members of the Hor-2 multigene family

Genome ◽  
1993 ◽  
Vol 36 (3) ◽  
pp. 397-403 ◽  
Author(s):  
Vladimir Kanazin ◽  
Evgeny Ananiev ◽  
Tom Blake
Keyword(s):  
Polymerase Chain Reaction ◽  
Gene Family ◽  
Storage Proteins ◽  
Gene Families ◽  
Reaction Sequence ◽  
Chain Reaction ◽  
Genes Encoding ◽  
Polymerase Chain ◽  
Encoding Gene ◽  
Barley Genotypes

The hordeins comprise the major prolamin storage proteins of barley. Two major and one minor gene families encode these alcohol-soluble proteins. The Hor-2 gene family encoding the B-hordeins has been estimated to contain 15–30 copies. Although several genes encoding B-hordeins have been cloned and sequenced, little is known about the mechanisms responsible for the generation of the enormous genetic variability at this locus. Polymerase chain reaction sequence amplification provided a simple technique that permitted the amplification of the Hor-2 gene family members from the genomes of several barley genotypes. Sequence analysis of clones permitted the identification of a region within the Hor-2 structural gene that appears to undergo recombinational and slippage-like gene conversion events. In this report we describe variability of the B-hordein genes, possible mechanisms responsible for it, and implications this may have on the evolution of prolamin-encoding gene families.Key words: barley, hordeins, polymerase chain reaction, polymorphism.

scholarly journals A1-3 chromosomal translocations in Italian populations of the peach potato aphid Myzus persicae (Sulzer) not linked to esterase-based insecticide resistance

2013 ◽  
Vol 103 (3) ◽  
pp. 278-285 ◽  
Author(s):  
Marco Rivi ◽  
Valentina Monti ◽  
Emanuele Mazzoni ◽  
Stefano Cassanelli ◽  
Michela Panini ◽  
...  
Keyword(s):  
Insecticide Resistance ◽  
Myzus Persicae ◽  
Chromosomal Rearrangements ◽  
Molecular Data ◽  
Chromosomal Translocations ◽  
Potato Aphid ◽  
Mediterranean Regions ◽  
The Mediterranean ◽  
First Time ◽  
Peach Potato Aphid

AbstractEsterase-based resistance in the peach-potato aphid, Myzus persicae (Sulzer), is generally due to one of two alternative amplified carboxylesterase genes, E4 or FE4 (fast E4). The E4 amplified form is distributed worldwide and it is correlated with a particular translocation between autosomes 1 and 3, whereas the FE4 form, which has hitherto not been found to be associated with chromosomal rearrangements, is typical of the Mediterranean regions. In this study, we present for the first time cytogenetic and molecular data on some M. persicae parthenogenetic lineages, which clearly show a chromosomal A1-3 translocation associated with esterase FE4 genes and unrelated to high levels of esterase-based resistance.

scholarly journals Cloning and analysis of the esterase genes conferring insecticide resistance in the peach-potato aphid, Myzus persicae (Sulzer)

1993 ◽  
Vol 294 (2) ◽  
pp. 569-574 ◽  
Author(s):  
L M Field ◽  
M S Williamson ◽  
G D Moores ◽  
A L Devonshire
Keyword(s):  
Insecticide Resistance ◽  
Dna Sequences ◽  
Myzus Persicae ◽  
Amino Acid Sequences ◽  
In Vitro Translation ◽  
Cdna Clones ◽  
Nucleotide Substitutions ◽  
Single Nucleotide ◽  
Potato Aphid ◽  
Peach Potato Aphid

Full-length cDNA clones encoding the esterases (E4 and FE4) that confer insecticide resistance in the peach-potato aphid [Myzus persicae (Sulzer)] were isolated and characterized. The E4 cDNA contained an open reading frame of 1656 nucleotides, coding for a protein of 552 amino acids. The FE4 cDNA shared 99% identity with E4 over this region, the most important difference being a single nucleotide substitution resulting in the FE4 mRNA having an extra 36 nucleotides at the 3′ end. The derived amino acid sequences for the N-terminus of E4 and FE4 were identical, with the first 23 residues being characteristic of a signal peptide and the next 40 residues being an exact match to the N-terminal sequence determined by Edman degradation of both purified proteins. The predicted molecular masses of 58.8 and 60.2 kDa for the E4 and FE4 polypeptides were consistent with those previously observed by in vitro translation of mRNA. Five potential N-linked glycosylation sites were present in both polypeptides, in accordance with earlier evidence that the native esterases are glycoproteins. Comparison of the aphid esterase protein sequences with other serine hydrolases provided evidence that their activity involves a charge-relay system with a catalytic triad the same as that found in acetylcholinesterase. Restriction mapping and sequencing of cloned genomic DNA showed that the E4 gene is spread over 4.3 kb with six introns and that the previously reported differences between the 3′ ends of the E4 and FE4 genes result from single nucleotide substitutions and not gross differences in the DNA sequences.

scholarly journals Analysis of amplicons containing the esterase genes responsible for insecticide resistance in the peach-potato aphid Myzus persicae (Sulzer)

1996 ◽  
Vol 313 (2) ◽  
pp. 543-547 ◽  
Author(s):  
Linda M. FIELD ◽  
Alan L. DEVONSHIRE ◽  
Chris TYLER-SMITH
Keyword(s):  
Gene Amplification ◽  
Myzus Persicae ◽  
Gene Copy Number ◽  
Fold Increase ◽  
Gene Copy ◽  
Potato Aphid ◽  
Gene Copies ◽  
Genes Encoding ◽  
Aphid Clone ◽  
Peach Potato Aphid

The amplification of genes encoding an insecticide-detoxifying esterase (E4) in the peach-potato aphid Myzus persicae is one of the few examples where this genetic phenomenon has been shown to be involved in the response of an intact higher organism to artificial selection. Here we report quantitative and qualitative studies of the repeat units (amplicons) containing the E4 genes in a highly resistant aphid clone. Initial studies to quantify esterase sequences showed a 5-11-fold increase in resistant aphids compared with susceptible aphids, suggesting the presence of 10-22 gene copies per diploid genome. A more incisive analysis by pulsed-field gel electrophoresis confirmed the presence of about 12 copies of the E4 gene and showed them to be on about 24 kb amplicons, arranged as a tandem array of direct repeats. This, together with previous results from crossing experiments and with recent in situ hybridization studies, confirms that the E4 gene amplification in this aphid clone is heterozygous at a single locus. However, these data show that the gene amplification alone cannot account for the approx. 60 times higher levels of E4 protein and its mRNA present in this aphid clone, and therefore resistance must involve changes in both esterase gene copy number and gene expression.

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