A naturally occurring chromosomal translocation in Myzus persicae (Sulzer)

Populations of M.persicae from glasshouses in Britain were found to have a structurally heterozygous chromosome complement. Biometric data from somatic metaphase chromosomes, and the pairing configurations of chromosomes at spermatocyte meiosis, indicate either a simple or a reciprocal translocation involving autosomes 1 and 3. All except one of the clones started from these populations showed high levels of esterase activity indicative of resistance to organophosphorus insecticides. The British translocated clones were all androcyclic in reproductive character, but of several distinct genotypes. A similar or identical translocation was found in seven out of nine clones started from M.persicae collected in the field in Japan. The translocation was present in Japanese M.persicae of all reproductive categories, being somehow maintained in the sexual breeding system of the aphid. In breeding experiments, translocation heterozygosity was inherited independently from colour and reproductive characters. The translocation was also found in a sample of M.persicae from southern California.     

Organic farming-compatible insecticides against the aphid Myzus persicae (Sulzer) in peach orchards

Abstract:  Three products allowed in organic farming (kaolin, mineral oil and insecticidal soap) as alternatives to chemical insecticides, were evaluated for the control of Myzus persicae (Sulzer) in a peach orchard. Their efficacy was compared with the neonicotinoid imidacloprid and an untreated control. The experiment was replicated for 2 years (2003 and 2004). The products were applied once in May every year and aphid infestation was recorded three to four times post-treatment. In 2004, the effect of the products on the predatory coccinellid species was also recorded. In 2003, all four products showed good control with average Abbott's efficiency ranging from 80% to 88%. In the next year, however, the products were less effective and only imidacloprid and kaolin reduced aphid population significantly compared with the untreated control, with an average Abbott's efficiency of 62% and 31%, respectively. This reduced efficiency was attributed to high rainfall occurring post-treatment. Regarding the effects on beneficial coccinellids, only imidacloprid and mineral oil reduced their numbers after application. The results showed that the three alternative products and especially kaolin are promising for aphid control in peach orchards. Kaolin has also low side-effects on beneficials and it could be used in organic peach orchards.     

Biological activities of lignans and neolignans on the aphid Myzus persicae (Sulzer)

Lignans and neolignans have been reported to exert different biological activities, including insecticidal ones. Three lignans, secoisolariciresinol (SECO), secoisolariciresinol diglucoside (SDG), and anhydrosecoisolariciresinol (AHS), and one neolignan, dehydrodiconiferyl alcohol-4-β-d-glucoside (DCG), were isolated from flax. Their insecticidal properties were evaluated on the aphid Myzus persicae reared on artificial diet. Life history parameters, i.e., nymphal survival, prereproductive period, and daily fecundity, were assessed and used to calculate the intrinsic rate of natural increase and the doubling time of aphid populations. Compared to the control, SDG and DCG significantly increased aphid mortality by at least 25 %, while SECO and AHS did not affect their survival. SDG did not affect life history parameters, except at the highest concentration of 100 μg/mL, which increased the population’s doubling time by more than 5 days. DCG altered all the life history parameters at all concentrations assayed. SECO induced significant deleterious effects on the aphids, except at the highest concentration of 100 μg/mL. AHS only altered prereproductive period, which increased by at least 2 days at 50 and 100 μg/mL. Lignans and neolignans are potential new bioinsecticides against aphids in the context of alternative management programs.     

Annotated expressed sequence tags and xenobiotic detoxification in the aphid Myzus persicae （Sulzer）

Aphids （Hemiptera： Aphididae） are phytophagous insects that are important agricultural pests. The enormous negative economic impacts caused by aphids worldwide are well known, and are mostly due to their high multiplication rate and the transmission of phytopathogenic viruses. Aphid management strategies mainly involve chemical treatments which are pollutants and are increasingly inefficient, since aphids have developed multiple insecticide-resistant mechanisms. Among the most economically important species is the green peach aptfid Myzus persicae Sulzer （Aphididae： Macrosiphini）, which is able to colonize a wide range of host plants belonging to many different families, and transmits numerous plant viruses. Because of its large prevalence, M. persicae has been the target of massive insecticide treatments; consequently, it has evolved several insecticide-resistant mechanisms. In this work, a collection of expressed genes from M. persicae is presented in order to identify putative genes involved in xenobiotic detoxification. After cDNA cloning and sequencing, 959 expressed sequence tags （EST） were annotated. Most sequences matched known genes corresponded to metabolism proteins （26%）, ribosomal proteins （ 23 % ） and structural proteins （8%）. Among them, several sequences corresponded to proteins putatively involved in sensing, degradation or detoxification of plant xenobiotic products.     

几种药剂对烟蚜毒力的温度效应

在15℃、20℃、25℃、30℃及35℃条件下分别测定了吡虫啉、丁硫克百威和氰戊菊酯对烟蚜毒力的温度效应.结果显示,吡虫啉和丁硫克百威对烟蚜的毒力呈正温度效应,但随着温度上升,烟蚜对吡虫啉的敏感性变化比丁硫克百威大.吡虫啉毒力在35℃时为15℃时的7.12倍;而丁硫克百威为2.88倍.氰戊菊酯对烟蚜的毒力呈负温度效应,在35℃时的毒力约为15℃时的1/5.鉴于这些药剂的毒力受温度影响的规律,建议在气温较低时选用氰戊菊酯等负温度效应的农药,在气温较高时则选用吡虫啉等正温度效应的农药,以充分发挥农药的性能,减少农药使用量、降低防治成本.     

Effect of the antimicrobial peptide indolicidin on the green peach aphid Myzus persicae (Sulzer)

Abstract:  The green-peach aphid, Myzus persicae (Sulzer) (Hem., Aphididae), is a major agricultural pest of a wide range of host plants, causing damage by feeding and indirectly by transmitting viruses. In this study we tested the effect of the antimicrobial peptide indolicidin on M. persicae survival and on its essential bacterial endosymbionts. Artificial diet bioassays showed a significant dose-dependent lethal response of indolicidin on M. persicae survival (LD₅₀ of 209 ± 60  μ g/ml). Histological analysis of indolicidin-treated aphids revealed a lower number of distorted mycetocytes, whereas control aphids showed abundant number of rounded and filled mycetocytes. These results suggest that aphid survival could be affected via reduction of its endosymbionts. Thus, aphid control based on antimicrobial substances against endosymbionts could be a promising strategy that needs to be further explored.     

Within-species variability of the response to 20-hydroxyecdysone in peach-potato aphid (Myzus persicae Sulzer)

Phytoecdysteroids have been proposed as new tools for controlling crop pests because of their endocrine disruption and deterrent effects on insects and nematodes. There is increasing evidence of variability between taxa in sensitivity to phytoecdysteroids, but the genetic variability of this sensitivity within species is unknown. However, knowledge about this intraspecies variability is required for predicting evolution of the pest's response to new control methods. We assessed the variability of the response of the aphid Myzus persicae Sulzer, a major agricultural pest, to 20-hydroxyecdysone (20E). We determined the number of nymphs produced by six clones of M. persicae exposed to various concentrations of 20E and the capacity of these clones to detect 20E in choice experiments. High concentrations of 20E significantly decreased the number of nymphs produced for two clones and both increases and decreases in the number of offspring were detected at low concentrations. Two clones significantly avoided food with 20E, while one significantly preferred it, suggesting that 20E does not always act as a deterrent in this species. We conclude that genetic variability in the response to 20E exists in natural populations of M. persicae. The consequences of this finding on the sustainability of control methods using 20E are discussed.     

The suitability of some plant hosts for the development of the peach-potato aphid, Myzus persicae (Sulzer)

Myzus persicae develop well on Brassica species, particularly those that grow rapidly, such as mustard and turnip, but much less well on sugar beet, spinach and lettuce. They usually develop better on young, rapidly growing leaves than on mature leaves. Two clones of M. persicae behaved similarly on the host plants tested.

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Zusammenfassung Die Entwicklung von Myzus persicae-Alienicolen auf den Sekundärwirten Kohlrüben, Kopfkohl, Chinakohl, Brokkoli, Blumenkohl, Senf, Raps, Grünkohl sowie Zuckerrübe, Spinat und Salat wurde durch wiederholte Erfassung der durchschnittlichen und totalen Larvenproducktion einzelner Jungfern sowie ihrer Mortalität in Gewächshausversuchen verfolgt und mit Auszählung des Befalls von Freilandpflanzen verglichen. Myzus persicae entwickelte sich gut an Brassica-Arten, besonders an raschwüchsigen wie Senf und Kohlrüben, aber viel weniger gut an Zuckerrübe, Spinat and Salat. Sie entwickelt sich gewöhnlich an jungen schnell wachsenden Blättern besser als an ausgereiften. Zwei Klone von Myzus persicae verhielten sich an den geprüften Wirtspflanzen ähnlich.

     

Inheritance and meiotic behaviour of a de novo chromosome fusion in the aphid Myzus persicae (Sulzer)

A de novo tandem fusion between autosomes 2 and 3 (A2+3), arising in the course of laboratory crosses of sexual morphs of two clones of the aphid Myzus persicae, was stable through more than 180 generations of parthenogenetic (clonal) reproduction. Studies of its inheritance through the sexual phase, and segregation from an amplified esterase marker gene, showed that crossing over occurred during oogenesis, but not in spermatogenesis, confirming previous cytological observations. Only a small number of progeny resulted from attempts at selfing fusion heterozygotes, and none of these was homozygous for the fusion. A2+3 paired in parallel alignment with the separate A2 and A3 to form a trivalent at prophase I of spermatogenesis. Fusion heterozygotes had a segregation problem at anaphase I of meiosis, A2+3 forming a chromatin bridge between the daughter spermatocytes in about 42% of dividing cells, which could be attributed to alternate orientation in the trivalent (A2 and A3 paired with opposite sides of A2+3) in the preceding metaphase I. Males heterozygous for an A2 dissociation were also studied and found to have much less of a segregation problem, despite showing similar orientation patterns at metaphase I. Possible reasons for this difference and the significance of the findings in relation to karyotype evolution in aphids are discussed.     

Studies on the morphometry of the green peach aphid, Myzus persicae (Sulzer) (Homoptera: Aphididae)

Aphids are one of the most important groups of phytophagous insects because of their polyphenism, host alternation, heteroecious behavior and reproductive habits. Laboratory culture of the aphid Myzus persicae on the host plant Brassica pekinensis Hubner was maintained seasonally for biometrical studies. The metric analysis revealed gradual developmental changes from the first instar nymph to the adult stage in size, shape, and a number of characters. The transitional changes were sufficiently distinct to allow differentiation of each of the life stages irrespective of the season. A key to the nymphal stages of the pest is provided.     

Segregation of autosomes during spermatogenesis in the peach-potato aphid (Myzus persicae) (Sulzer) (Hemiptera: Aphididae)

Most aphids are cyclic parthenogens, so are ideal models in studies of the mechanisms and consequences of sex and recombination. However, owing to a shortage of physical and genetic markers, there have been few studies of the most fundamental genetic processes in these organisms. For example, it is not known whether autosomal segregation during male spermatogenesis is in Mendelian proportions: we address that question here. The aphid Myzus persicae has a typical karyotype of 2n = 12 in females (XX), while males are XO (2n = 11). During male meiosis, only the spermatocytes with an X chromosome are viable. We hypothesized that assortment of autosomes might be non-random because chromosomal imprinting leading to elimination of the paternal autosomes is seen in the closely related coccoids. In other aphid models, we have observed segregation distortions at single microsatellite loci (Wilson, 2000). Such distortions may have nothing to do with 'selfish' behaviour, but may be caused by mutation accumulation causing fitness differentials. Thus single-locus distortions might be predicted to be more likely to be detected via the male lines of clones that have lost the ability to reproduce sexually (male-producing obligate parthenogenesis (androcyclic)). Using microsatellites we show that genetic imprinting or selfish autosome behaviour does not occur in male M. persicae. Generally, loci segregated in Mendelian proportions in both sexes of cyclically parthenogenetic (holocyclic) clones. However, in androcyclic clones, segregation distortions consistently involved the same two autosomes. This is consistent with linkage of markers to deleterious mutations associated with a loss of sexual reproduction.     

Ultrastructure of antennal sensilla of the peach aphid Myzus persicae Sulzer, 1776

The antennal sensilla of alate Myzus persicae were mapped using transmission electron microscopy and the ultrastructure of sensilla trichoidea, coeloconica, and placoidea are described. Trichoid sensilla, located on the tip of the antennae, are innervated by 2–4 neurons, with some outer dendrites reaching the distal end of the hair. Coeloconic sensilla in primary rhinaria are of two morphological types, both equipped with two dendrites. Dendrites of Type II coeloconic sensilla are enveloped in the dendrite sheath, containing the sensillum lymph. In sensilla coeloconica of Type I, instead, dendrites are enclosed by an electron opaque solid cuticle, with no space left for the sensillum lymph. The ultrastructure of big placoid sensillum reveals the presence of three groups of neurons, with 2–3 dendrites in each neuron group, while both small placoid sensilla are equipped with a single group of neurons, consisting of three dendrites. Both large and small placoid sensilla bear multiple pores on the outer cuticle. The function of these sensilla is also discussed. J. Morphol. 276:219–227, 2015. © 2014 Wiley Periodicals, Inc.     

Toxicity of Nicotiana gossei domin to Myzus persicae (Sulzer)

Resistance in Nicotiana species to the green peach aphid appears to result from the production of a toxic material produced by the aerial parts of the plant. Materials exuded from the leaf hairs which are transferred to glass micro-beakers are toxic to several species of aphids. The symptoms of such poisoning resemble those of nicotine poisoning, but resistance does not appear to be correlated with the amount of nicotine in the leaf.

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Zusammenfassung Nicotiana-Arten erzeugen einen Stoff, der für die grüne Pfirsichlaus, Myzus persicae und verschiedene andere Blattlausarten giftig ist. Dieser Giftstoff scheint von den Haaren der Pflanzen ausgeschieden zu werden. Er wird von den Blattläusen aufgenommen, während sie über die Pflanzen laufen, und vermutlich durch die Kutikula absorbiert. Wenn man diese Exsudate mit Kamelhaarpinseln von den Blättern resistenter Pflanzen in Mikrobecher überträgt, werden die Blattläuse verschiedener Art getötet, sobald sie in diese Becher gesetzt werden. Die von N. gossei, einer hoch resistenten Art, übertragene Substanz blieb in diesen Behältern wenigstens 28 Tage lang toxisch.Das erste Symptom der Vergiftigung ist eine Lähmung der Hinterbeine. Die beiden anderen Beinpaare werden kurz danach betroffen, sodass sich die Blattläuse nicht mehr aufrecht halten können. Die Endsymptome bestehen in ziemlich raschen, jedoch nicht heftigen Zuckungen der Beine und Antenne. Es scheint keinerlei Beziehung zwischen der Anfälligkeit der Nicotiana-Arten und der Nicotiana tabacum-Sorten durch die Grüne Pfirsichlaus und dem Nikotingehalt der Blätter zu bestehen. Reziproke interspezifische Pfropfungen zwischen resistenten und anfälligen Nicotiana-Arten verursachen keinerlei Veränderungen in der Resistenz von Unterlagen und Reissern.

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The investigation reported in this paper is in connection with a project of the Kentucky Agricultural Experiment Station and is published with the approval of the Director.     

Continuous occurrence of intra-individual chromosome rearrangements in the peach potato aphid, Myzus persicae (Sulzer) (Hemiptera: Aphididae)

Analysis of the holocentric mitotic chromosomes of the peach-potato aphid, Myzus persicae (Sulzer), from clones labelled 50, 51 and 70 revealed different chromosome numbers, ranging from 12 to 14, even within each embryo, in contrast to the standard karyotype of this species (2n?=?12). Chromosome length measurements, combined with fluorescent in situ hybridization experiments, showed that the observed chromosomal mosaicisms are due to recurrent fragmentations of chromosomes X, 1 and 3. Contrary to what has generally been reported in the literature, X chromosomes were frequently involved in recurrent fragmentations, in particular at their telomeric ends opposite to the nucleolar organizer region. Supernumerary B chromosomes have been also observed in clones 50 and 51. The three aphid clones showed recurrent fissions of the same chromosomes in the same regions, thereby suggesting that the M. persicae genome has fragile sites that are at the basis of the observed changes in chromosome number. Experiments to induce males also revealed that M. persicae clones 50, 51 and 70 are obligately parthenogenetic, arguing that the reproduction by apomictic parthenogenesis favoured the stabilization and inheritance of the observed chromosomal fragments.     

桃蚜自然种群初级和次级共生菌的分子鉴定

蚜虫不仅带有专性初级内共生菌,还常常带有不同类群的兼性次级共生菌。本研究采用真细菌16S rDNA的通用引物,从桃蚜Myzus persicae (Sulzer)烟草种群体内扩增出1.5 kb的共迁移目的条带,然后将其克隆,并在阳性克隆筛选时进行了RFLP分析。当采用EcoRⅠ进行单酶切分析时,目的片段被切割成～650 bp和～850 bp两个小片段;当采用EcoRⅠ和HindⅢ进行双酶切分析时,该蚜群共生菌酶切谱带被分成2组,其中1组(GroupⅠ)只具有一个EcoRⅠ酶切位点,而另1组(Group Ⅱ)不仅具有一个EcoRⅠ酶切位点,还具有一个HindⅢ酶切位点,而且GroupⅠ为优势共生菌群。在此基础上分别对2组共生菌的16S rDNA全序列（～1.5 kb）进行了测定,结果表明：GroupⅠ属于泛菌属Pantoea,与成团泛菌Pantoea agglomerans亲缘关系最近（同源性达99.70%）,而Group Ⅱ属于蚜虫的专性内共生菌,即Buchnera aphidicola（同源性达99.50%）。这是在蚜虫体内存在泛菌次级共生菌的首次报道。     

混配杀虫剂对烟蚜的毒力测定

选用氰戊菊酯乳油为底药,与其它3种药剂分别按有效成份进行不同比例的混配,测定其对烟蚜的毒力差异.实验结果表明:氰戊菊酯乳油与辛硫磷乳油按3:2进行混配时,其共毒系数最大,为825.96;其次是按1:1进行混配时,其共毒系数为462.45;最小的为2:3进行混配时,其共毒系数为244.62.氰戊菊酯乳油与灭多威乳油按1:1进行混配时,其共毒系数最大,为367.09;其次是按3:2进行混配时,其共毒系数为297.08;最小的为2:3进行混配时,其共毒系数为157.32.氰戊菊酯乳油与吡虫啉按2:3进行混配时,其共毒系数最大,为1558.28;其次是3:2进行混配时,其共毒系数为603.01;最小的为1:1进行混配时,其共毒系数为326.13.各个配比的共毒系数均大于100,均表现出增效作用.     

寄主转换对烟蚜种群特征的影响

试验结果表明：除从油菜上转到桃树上不成功外,烟蚜可在昌,油菜和桃树之间的成功转换,且同寄主之间的转换比异寄主之间的转换生殖前期短,产仔量大。烟蚜寄主转换以ｒｍ值的大小依次为桃树转油菜－烟草转油菜－油菜转烟草－桃树转烟草－烟草转桃树。     

Fast chromosomal evolution and karyotype instability: recurrent chromosomal rearrangements in the peach potato aphid Myzus persicae (Hemiptera: Aphididae)

The occurrence of karyotype variations with respect to both chromosome number and structure has been frequently reported in aphids. Here, we review recent data attesting to the presence of recurrent chromosomal changes in the karyotype of the peach potato aphid Myzus persicae, where clones presenting metaphases with different chromosome number (from 12 to 17) have been observed, also comparing plates obtained within the same embryo. According to the available data, M. persicae autosomes 3 and 1 are the chromosomes mostly involved in changes compared to other autosomes, suggesting that they could have sites more susceptible to fragmentation. Chromosomal fissions involving the X chromosomes have also been observed, suggesting that they may have fragile sites located at the termini opposite to the nucleolar organizer regions‐bearing telomere. The presence of holocentric chromosomes and reproduction by apomictic parthenogenesis, together with a constitutive expression of telomerase, could explain the inheritance of the observed chromosomal instability in aphids. Considering that chromosomal changes may affect the host choice and could also favour speciation, it would be intriguing to confirm whether the observed karyotype variants have effects over short temporal and spatial scales.