Recent changes in the distribution of carboxylesterase genes and associated chromosomal rearrangements in Greek populations of the tobacco aphidMyzus persicae nicotianae

Abstract

We present data on the frequency of amplified E4 and FE4 carboxylesterase genes in Myzus persicae s.l. clones collected during the years 2002-2007 and 2012 in Greece. Most clones were of the tobacco aphid, Myzus persicae nicotianae. Samples from 2012 were genotyped with microsatellite DNA markers and a number of them were karyotyped. Aphid clones with amplified FE4 genes predominated in all years, whereas E4 was present in only 3.5% of all samples and always occurred in clones with FE4. Most of the clones examined showed high carboxylesterase activity levels (R2 resistant category). The results showed marked changes in the frequencies of the two carboxylesterase genes in the tobacco aphid populations compared to published data that were collected in Greece in the mid 1990s, when E4 was recorded on its own in 20% of all samples and in 32% of samples from tobacco. A parallel change in karyotype was also observed because the A1,3 translocation, which had a worldwide association with amplified E4 genes in the 1990s, was not detected in the clones analyzed in 2012. Possible causes for these changes are discussed, although selection as a result of pest management practices appears to be the major one. Novel chromosomal rearrangements were also found in M. persicae nicotianae clones. These rearrangements could be a result of clastogenic effects of nicotine, which could persist because of the holocentric nature of aphid chromosomes. The results are discussed in relation to rapid evolution events that have taken place in the tobacco aphid in Greece during the last two decades.

Evolution of imidacloprid resistance in Myzus persicae in Greece and susceptibility data for spirotetramat

“…Indeed, populations/genotypes that exhibit all or most of the resistance mechanisms are not uncommon in Greece and their control with conventional chemical insecticides is becoming difficult . Thus, regular monitoring of the aphid populations accompanied with historical data (see, for example, the evolution of carboxylesterase genes and associated chromosomal rearrangements in the nicotianae populations in Greece) helps to advise for the potential of resistance development and provide information for efficient pest control and resistance management. For that reason we compared samples from different regions, crops and years and we included both M. persicae sub‐species and populations with different frequencies of sexual/asexual genotypes (peach vs. tobacco) …”

“…Considering the traits of aphid biology (short generation times, high fecundity, high rates of population increase, combination of sexual and asexual reproduction) and that cases of rapid evolution events (i.e. changes over perceptible timescales) have already been reported in M. persicae (especially in the nicotianae sub‐species), the selection of a similar P450‐based mechanism capable of detoxifying spirotetramat would seem a realistic possibility, especially when considering the current intense use of this compound. Thus, in order to ensure the sustainable use of spirotetramat, users should carefully follow the resistance management guidelines that have been designed for this product…”

Effect of synthetic insecticides on the larvae of Coccinella septempunctata from Greek populations

“…Foster et al (2007), in their review, cite 13 resistant species, some of them being resistant to six different insecticide groups such as neonicotinoid, pyrethroid and organophosphate insecticides. Among these species important pests are included, such as: M. persicae (Margaritopoulos et al 2007;Kati et al 2014;Voudouris et al 2016Voudouris et al , 2017, A. gossyppii (Shi et al 2011;Herron and Wilson 2011), and Aphis fabae (Scopoli) (Hemiptera: Aphididae) (Ioannidis 2000).…”

Genomic and Cytogenetic Localization of the Carotenoid Genes in the Aphid Genome

“…The standard karyotype of M. persicae comprises 12 chromosomes, including 5 pairs of homologous autosomes and 2 X chromosomes, but several variations in chromosome number and structure have been recently observed in Italy and Greece [Monti et al, 2011[Monti et al, , 2012aRivi et al, 2012Rivi et al, , 2013Kati et al, 2014]. In particular, the most common M. persicae chromosomal variant consists of a reciprocal translocation between autosomes 1 (A1) and 3 (A3) resulting in females with 12 chromosomes with a marked structural difference in heterozygotes [Blackman, 1980;Manicardi et al, 2015b].…”