RESUMO
A novel system for spider mite control was developed with a slow-release sachet containing Neoseiulus californicus (McGregor) (Acari: Phytoseiidae) protected by a waterproof shelter. Monitoring the efficacy of the predator release system for spider mite control at a Japanese pear greenhouse requires discrimination of N. californicus from other indigenous phytoseiid mite species inhabiting the study site and subsequent identification of the released N. californicus. The report of our earlier study described a PCR-based method for discrimination of N. californicus species. For the present study, we first examined phytoseiid mite species composition in the greenhouse. Subsequently, we developed microsatellite markers to identify the released N. californicus. Finally, we installed the predator release system in the greenhouse and conducted a population survey of phytoseiid and spider mites. Results demonstrated that approximately 1 month is necessary for distribution of the released N. californicus on the leaves.
Assuntos
Ácaros e Carrapatos/fisiologia , Controle Biológico de Vetores , Pyrus/parasitologia , Tetranychidae , Animais , Japão , Comportamento Predatório , Controle de Ácaros e CarrapatosRESUMO
Herbivore-induced plant volatiles (HIPVs) are important cues for natural enemies to find their hosts. HIPVs are usually present as blends and the effects of combinations of individual components are less studied. Here, we investigated plant volatiles in a tritrophic system, comprising the parasitoid wasp Lytopylus rufipes Nees (Hymenoptera: Braconidae), the Oriental fruit moth Grapholita molesta (Busck) (Lepidoptera: Tortricidae), and Japanese pear, Pyrus pyrifolia 'Kosui', so as to elucidate the effects of single components and blends on wasp behaviors. Bioassays in a four-arm olfactometer, using either shoots or their isolated volatiles collected on adsorbent, revealed that female wasps preferred volatiles from host-infested shoots over those from intact shoots. Analyses identified (Z)-3-hexenyl acetate (H), linalool (L), (E)-ß-ocimene (O), (E)-3,8-dimethyl-1,4,7-nonatriene (D), and (E,E)-α-farnesene (F). Among them, only F was induced by infestation with G. molesta. When tested singly, only O and D elicited positive responses by L. rufipes. Binary blends of HO and DF elicited a positive response, but that of HD elicited a negative one, even though D alone elicited a positive response. Remarkably, wasps did not prefer either the ODF or HL blends, but showed a highest positive response to a quinary blend (HLODF). These results show that synergism among volatiles released from host-infested plants is necessary for eliciting high behavioral responses in L. rufipes, enabling L. rufipes to find its host efficiently.
Assuntos
Comportamento de Busca por Hospedeiro/efeitos dos fármacos , Pyrus/química , Compostos Orgânicos Voláteis/farmacologia , Vespas/fisiologia , Monoterpenos Acíclicos , Alcenos/farmacologia , Animais , Comportamento Animal/efeitos dos fármacos , Feminino , Cromatografia Gasosa-Espectrometria de Massas , Herbivoria , Mariposas/fisiologia , Brotos de Planta/química , Brotos de Planta/metabolismo , Brotos de Planta/parasitologia , Pyrus/metabolismo , Pyrus/parasitologia , Sesquiterpenos/farmacologia , Compostos Orgânicos Voláteis/químicaRESUMO
Cydia pomonella, Euzophera pyriella Yang, and Grapholitha molesta are destructive pest species of Korla fragrant pears in Xinjiang. They are also quarantine pests of concern in a number of countries. Identification of these small pest larvae by morphological characters is difficult, and misidentifications will influence appropriate quarantine decisions. Here, a 520 bp fragment of mitochondrial cytochrome oxidase subunit I (COI) was first amplified and sequenced from each species, and a diagnostic region was observed. Subsequently, the species-specific primer and probe sets of quantitative real-time PCR (qPCR) were designed, which amplified a 114-116 bp fragment of COI genes. This method was validated by amplification DNA extracted from single, multiple, and mixed pest samples. Results indicated that this method allows rapid discrimination and reliable identification of larvae, pupae, and adult specimens of all three species, which could help the international export trading of Korla fragrant pears and related products.
Assuntos
Complexo IV da Cadeia de Transporte de Elétrons/genética , Lepidópteros/classificação , Pyrus/parasitologia , Animais , Proteínas de Insetos/genética , Lepidópteros/genética , Filogenia , Reação em Cadeia da Polimerase , Análise de Sequência de DNA , Especificidade da EspécieRESUMO
The oriental fruit moth Grapholita molesta (Busck) is a globally important insect pest. In some parts of its geographic range, the oriental fruit moth shifts its attack from peach orchards to pear orchards late in the growing season. The phenological effects of host plants on the performance of the moth were evaluated by examining the development and fecundity of the moth reared on peach (Prunus persica variety "Shahong") and pear (Pyrus bretshneideri variety "Dangshan Su") collected at various times of the growing season under laboratory conditions. Results showed that the moth developed faster on shoots and fruits of peach than on those of pear. The preimaginal survival rate was the highest on peach shoots, and the moth could not survive on pear fruit collected on May 10. For both peach and pear, the boring rates of neonatal larvae were significantly higher on shoots than on fruits, and the pupal mass of females was significantly higher on fruits than on shoots. The boring rate increased with pear fruits growing during later days. Fecundity was significantly less on pear shoots than on the other plant materials. The results of this study suggest a possible host adaptation process in oriental fruit moth.
Assuntos
Fertilidade , Mariposas/crescimento & desenvolvimento , Prunus persica/parasitologia , Pyrus/parasitologia , Animais , Comportamento Alimentar , Feminino , Frutas/parasitologia , Larva/crescimento & desenvolvimento , Mariposas/fisiologia , Brotos de Planta/parasitologia , Estações do AnoRESUMO
The European pear psylla, Cacopsylla pyri L. (Hemiptera: Psyllidae), is one of the most serious arthropod pests of pear. Since proper control of this pest is essential, better understanding of the complex plant-pest relationship is mandatory. This research deals with constitutive polyphenolic profiles in leaves of 22 pear cultivars of diverse origin (P. communis, P. pyrifolia, and P. pyrifolia × P. communis) and different resistance to psylla. The study was designed to show which differences in the polyphenolic profile of leaves from resistant and susceptible pear cultivars could be utilized as information in subsequent breeding programs. The results demonstrated that the leaves of Oriental pear cultivars contained much higher amounts of p-hydroxybenzoic acid, ferulic acid, aesculin, and naringin, that, together with detected 3-O-(6â³-O-p-coumaroyl)-hexoside, apigenin, apigenin 7-O-rutinoside, and hispidulin, indicated a clear difference between the species and might represent phenolics responsible for psylla resistance.
Assuntos
Hemípteros/fisiologia , Doenças das Plantas/parasitologia , Folhas de Planta/química , Polifenóis/química , Pyrus/parasitologia , Animais , Resistência à Doença , Doenças das Plantas/imunologia , Folhas de Planta/imunologia , Folhas de Planta/parasitologia , Polifenóis/imunologia , Pyrus/química , Pyrus/imunologiaRESUMO
BACKGROUND: The pear psylla, Cacopsylla pyri L. (Hemiptera: Psyllidae), is one of the most serious insect pests of pears in Turkey. In recent years, psyllid management has become increasingly difficult because of the development of insecticide resistance and the withdrawal of registered chemicals from the market. In this study, the field efficacy of an emulsifiable concentrate formulation of the entomopathogenic fungus, Metarhizium brunneum Petch strain F52 (Hypocreales: Clavicipitaceae), containing 5.5 × 10(9) conidia mL(-1) , was evaluated against C. pyri in south-western Turkey (Antalya) in two consecutive years, 2010 and 2011. RESULTS: The results showed that the F52 product at 100 mL 100 L(-1) water reduced the number of psyllid eggs and young nymphs (first and second instars), causing up to 79 and 88% mortality, respectively, 7 days after treatment in the first year, and 72 and 82% mortality in the second year. However, it was less active against the older nymphs (third to fifth instars ) and achieved only up to 51% mortality 7 days after treatment in the first year, and 48% mortality in the second year. CONCLUSION: The results suggest that the M. brunneum strain F52 product can be used as an alternative to conventional chemicals in controlling C. pyri early in the season.
Assuntos
Hemípteros/microbiologia , Metarhizium/fisiologia , Controle Biológico de Vetores/métodos , Doenças das Plantas/parasitologia , Pyrus/parasitologia , Animais , Feminino , Hemípteros/fisiologia , Masculino , Doenças das Plantas/prevenção & controle , TurquiaRESUMO
BACKGROUND: Codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae), is a major pest of apple, pear and walnut production in North America. Management programs are based on preventing larval entry into the fruit or nut and are typically timed by heat-driven models that are synchronized to field populations by first capture of overwintering moths in pheromone traps. Unfortunately, trap capture is affected by a range of environmental parameters as well as by the use of mating disruption, which makes detecting first flight difficult, thus complicating implementation of management programs. The present goal was to evaluate data collected from a broad range of locations across North America to see whether average first spring emergence times could be predicted. RESULTS: Average emergence time on a degree-day scale from 1 January was predictable using latitude and elevation. Sites at elevations of <400 m fit a simple quadratic equation using latitude, but, when higher elevations were included, a multiple regression using elevation was required. CONCLUSIONS: The present models can be used to simplify management programs for codling moth in areas where heat-driven models that require extensive trapping to synchronize with emergence are currently used.
Assuntos
Controle de Insetos , Mariposas/crescimento & desenvolvimento , Animais , Larva/crescimento & desenvolvimento , Malus/parasitologia , Modelos Biológicos , América do Norte , Doenças das Plantas/parasitologia , Doenças das Plantas/prevenção & controle , Pyrus/parasitologia , Estações do AnoRESUMO
In the Belgian fruit growing area, sawflies are generally common but minor pests in pome fruit. Though, intensity and frequency of sawfly damage in apple and pear is increasing the last years in IPM and especially in organic orchards. The main species are apple sawfly (Hoplocampa testudinea Klug) and pear sawfly (Hoplocaompa brevis Klug) and recently also pear shoot sawfly (Janus compressus Fabricius). Here we report efficacy results on all three sawfly species fromtrial of three consecutive years (2011, 2012, and 2013). Flights and embryonic development were monitored and small plot efficacy trials were executed. Control of apple sawfly was complete (97.6% Abbott -trial 2011) when thiacloprid at 120 g/ha LWA was applied at the moment embryos are visible in the sawfly eggs. In 2012, a trial was executed on pear sawfly. Applications with thiacloprid were executed when the embryo was visible in the pear sawfly eggs and earlier at the start of egg laying. At both application timings, 100% Abbott efficacy was reached. A number of other active ingredients were tested at the moment embryos are visible in the sawfly eggs and very interesting efficacy results were reached for thiofanate-methyl, indoxacarb, spinosad, pyrethrins + piperonyl butoxide (PBO) and acetamiprid. In 2013, a preflowering application with pyrethrins + PBO reached the highest control against this pest. The most effective active ingredients of the pear sawfly trial were applied also in a trial on pear shoot sawfly. Efficacies were low or lacking, except for thiacloprid. Thiacloprid is in pear growing in Belgium only registered before flowering and after harvest. Therefore further research is needed to test the effect of earlier applications against this pest. This is a valuable efficacy study on occasionally occurring pests that are able to cause considerable economic losses.
Assuntos
Himenópteros/efeitos dos fármacos , Inseticidas/farmacologia , Malus/parasitologia , Doenças das Plantas/prevenção & controle , Pyrus/parasitologia , Animais , Himenópteros/crescimento & desenvolvimento , Controle de Insetos , Doenças das Plantas/parasitologiaRESUMO
Detailed information on plant penetration activities by pear psylla Cacopsylla pyri L. (Hemiptera Psyllidae) is essential to study phytoplasma transmission of "Candidatus Phytoplasma pyri" responsible of pear decline disease (PD) and to trace and evaluate resistant traits in new pear tree selections for advanced breeding programs. The electrical penetration graph technique or (full) EPG may relevantly contribute to this knowledge. C. pyri EPG waveforms were characterized on basis of amplitude, frequency, voltage level, and electrical origin. Additionally, stylet tracks and the putative location of stylet tips in the plant tissue were histologically related to EPG waveforms by light and transmission electron microscopy observations after stylectomy. More than one waveform occurred in the same tissue: PA, PB, PC1 and PC2 were all detected in the mesophyll, and PE1 and PE2 were both recorded in the phloem. Waveform PE1 was always preceded by transient waveform PD, as previously described in other psyllids. Interestingly, no brief intracellular punctures (potential drop waveforms) were observed during plant penetration, opposite of what is usually recorded in aphids and other Sternorrhyncha.
Assuntos
Comportamento Alimentar/fisiologia , Hemípteros/fisiologia , Pyrus/parasitologia , Animais , Fenômenos Eletrofisiológicos , Hemípteros/ultraestrutura , Microscopia Eletrônica de Transmissão , Ninfa/fisiologiaRESUMO
Estimation of demographic parameters is important for understanding the functioning of natural populations and the underlying ecological and evolutionary processes that may impact their dynamics. Here, we used sibship assignment methods to shed light on the local dynamics of codling moth females in eight orchards in a 90-ha domain near Valence, France. Based on full-sib inference among 1,063 genotyped moths, we estimated (1) the effective number of females that had offspring, (2) their fertility and (3) the distribution of their oviposition sites within and among orchards. The average number of females in all the orchards increased between the first (~130) and the second (~235) annual generations. The average fertilities of the females were similar at each generation according to the host plant considered (apple, pear, or walnut), but differed between commercial (~10) and non-treated (~25) apple orchards. Females mainly clustered their eggs on contiguous trees along orchard borders, but they also occasionally dispersed their eggs among different orchards independently of the cultivated host plants or the inter-orchard distances (up to 698 m) during the second annual generation. The mean distance between two oviposition sites was 30 m. Sibship estimates of both the effective number of females and the inter-orchard migration rates (~5%) were in agreement with the observed genetic differentiation among the eight orchards (0.006 < F ( st ) < 0.013). These results confirm and extend previous field and laboratory observations in Cydia pomonella, and they demonstrate that sibship assignments based on genetic data are an interesting alternative to mark-release-recapture methods for inferring insect population dynamics.
Assuntos
Estruturas Genéticas/genética , Mariposas/genética , Irmãos , Migração Animal , Animais , Simulação por Computador , Demografia , Feminino , Fertilidade , França , Frutas/parasitologia , Deriva Genética , Loci Gênicos , Marcadores Genéticos , Genótipo , Juglans/parasitologia , Escore Lod , Malus/parasitologia , Repetições de Microssatélites/genética , Mariposas/fisiologia , Dinâmica Populacional , Pyrus/parasitologia , Reprodução/genéticaRESUMO
BACKGROUND: Increasing attention has been paid to enhancing biological control through habitat management in agricultural systems for enhanced pest management. Pest management benefits can be realised by intercropping, which can increase natural enemy abundance and, in turn, reduce pest abundance. In this study, the composition and temporal dynamics of arthropod communities in pear orchards when intercropped with aromatic plants were investigated, and the effectiveness and applicability of aromatic plants as intercrops for enhancing insect control were assessed. RESULTS: When compared with natural grasses or clean tillage, intercropping significantly reduced pest abundance and increased the ratio of natural enemies to pests. Intercropping also shortened the occurrence duration and depressed the incidence peak in annual dynamics curves of the pest subcommunity and the arthropod community, mainly because of the repellent effects of aromatic plants. Equally important, intercropping significantly reduced the numbers of major pests, such as Psylla chinensis, Aphis citricola and Pseudococcus comstocki, while their incidence period was delayed to varying degrees, and the numbers of their dominant natural enemies (Coccinella septempunctata, Phytoseiulus persimilis and Chrysoperla sinica) increased. CONCLUSION: Intercropping with aromatic plants led to a considerable improvement in arthropod pest management by enhancing the activity of the beneficial arthropod community within the pear orchard ecosystem.
Assuntos
Ageratum/crescimento & desenvolvimento , Artrópodes/fisiologia , Ocimum basilicum/crescimento & desenvolvimento , Controle Biológico de Vetores/métodos , Doenças das Plantas/parasitologia , Pyrus/parasitologia , Satureja/crescimento & desenvolvimento , Satureja/metabolismo , Ageratum/metabolismo , Agricultura , Animais , Repelentes de Insetos/metabolismo , Ocimum basilicum/metabolismo , Doenças das Plantas/prevenção & controle , Pyrus/crescimento & desenvolvimentoRESUMO
The means by which European mountain ash ringspot-associated virus (EMARaV), a minus-strand ssRNA virus and the type member of the genus Emaravirus, is naturally spread, is unknown. In attempts to identify an EMARaV vector, galls induced by the eriophyid mite Phytoptus pyri were frequently found on infected leaves. By immunofluorescence microscopy, the presence of EMARaV nucleocapsid protein P3 was demonstrated in P. pyri individuals collected from diseased plants. Furthermore, RT-PCR analysis of entire P. pyri individuals revealed the presence of both viral genomic ss(-)RNAs and antigenomic ss(+)RNAs, suggesting that P. pyri might be a candidate vector of EMARaV.
Assuntos
Ácaros e Carrapatos/virologia , Bunyaviridae/genética , RNA Viral , Sorbus/virologia , Proteínas Virais , Ácaros e Carrapatos/ultraestrutura , Animais , Bunyaviridae/isolamento & purificação , Microscopia Eletrônica de Varredura , Folhas de Planta/parasitologia , Tumores de Planta/parasitologia , Pyrus/parasitologia , RNA Viral/genética , RNA Viral/isolamento & purificação , Proteínas Virais/genética , Proteínas Virais/isolamento & purificaçãoRESUMO
Mealybugs are under a strict regulation at foreign trades of agricultural products because they are one of the most economically damaging groups of insects on food crops and ornamental plants. However, the absence of morphological characteristics enabling the discrimination of early life stages often cause a significant delay or rejection of a shipment when infested fruit is discovered, causing significant economic loss. A polymerase chain reaction-based method for species identification was developed for six mealybug species known to infest Korean pears including two regulated insects, Planococcus kraunhiae (Kuwana) and Crisicoccus matsumotoi (Siraiwa). Six sets of species-specific primers were designed based on the sequence comparison of the internal transcribed spacer 1 and 2 regions. Efficiency tests against 29 mealybug samples showed that this method could effectively discriminate different mealybug species regardless of their developmental stages. Blind tests against 11 field collected mealybug nymph samples indicated that a single polymerase chain reaction is enough to discriminate unidentified mealybugs collected on Korean pears. This new method will facilitate trade and export requirements, as well as identify the species at any stage of mealybug intercepted.
Assuntos
Hemípteros/classificação , Hemípteros/genética , Pyrus/parasitologia , Animais , DNA Espaçador Ribossômico/genética , Variação Genética , República da Coreia , Especificidade da EspécieRESUMO
During the 1960s, the California pear industry, on a per acre basis, was among the heaviest users of pesticides. Each season, multiple sprays of up to 14 active ingredients (chlorinated hydrocarbons, organophosphates and carbamates) were typically applied for control of insects and mites. The cost of control escalated while damage from arthropod pests increased owing to greater pest resistance and more pest resurgence. The pear industry suffered classic symptoms of the 'pesticide treadmill'. By the late 1960s, key pear industry leaders demanded action. Simultaneously, newly emerging concepts of IPM were being developed and funded. With public awareness and environmental activism on the rise in the wake of Rachel Carson's Silent Spring, the stage was set for change. This paper elucidates how pear growers, university researchers and extension agents, environmentalists, government regulators, private consultants, farm chemical suppliers and others contributed to the reduction in insecticide use in California pear orchards. Today, arthropod IPM in pears is characterized as relatively low input, biologically intensive and very successful. For example, in 2008 many pear growers only applied between three and five active ingredients (mainly organically certified) per season for control of arthropods.
Assuntos
Controle de Pragas/história , Praguicidas/história , Doenças das Plantas/parasitologia , Pyrus/parasitologia , Animais , Artrópodes/efeitos dos fármacos , Artrópodes/fisiologia , California , História do Século XX , Controle de Pragas/métodos , Controle Biológico de Vetores/história , Controle Biológico de Vetores/métodos , Praguicidas/farmacologia , Doenças das Plantas/históriaRESUMO
Anoplophora glabripennis, the Asian longhorned beetle, is a wood-boring insect that can develop in a wide range of healthy deciduous hosts and requires gut microbes to aid in wood degradation and digestion. Here we show that larval A. glabripennis harbor a diverse gut bacterial community, and this community can be extremely variable when reared in different host trees. A. glabripennis reared in a preferred host (Acer saccharum) had the highest gut bacterial diversity compared with larvae reared either in a secondary host (Quercus palustris), a resistant host (Pyrus calleryana), or on artificial diet. The gut microbial community of larval A. glabripennis collected from field populations on Brooklyn, NY, showed the highest degree of complexity among all samples in this study. Overall, when larvae fed on a preferred host, they harbored a broad diversity of gut bacteria spanning the alpha-, beta-, gamma-Proteobacteria, Firmicutes, Actinobacteria, and Bacteroidetes. Cellulase activities (beta-1,4-endoglucanase, beta-1,4-exoglucanase, and beta-1,4-glucosidase) in the guts of larvae fed in a preferred host (A. saccharum) or a secondary host (Q. palustris) were significantly higher than that of artificial diet fed larvae. Larvae that fed on wood from a resistant host (P. calleryana) showed suppressed total gut cellulase activity. Results show that the host tree can impact both gut microbial community complexity and cellulase activity in A. glabripennis.
Assuntos
Celulase/metabolismo , Besouros/microbiologia , Trato Gastrointestinal/microbiologia , Árvores , Acer/parasitologia , Animais , Besouros/enzimologia , Trato Gastrointestinal/enzimologia , Larva/enzimologia , Larva/microbiologia , Pyrus/parasitologia , Quercus/parasitologiaRESUMO
Predatory bugs (Anthocoris sp.) are key predators of the pear sucker (Psyllo pyri) in pear orchards. In order to enhance biological control it is important to verify if crop protection products applied against Psylla pyri display potential short- or long-term detrimental effects on Anthocoris populations. This study focuses on the impact of thiacloprid (Calypso 480 SC), applied at preblossom for the control of the first generation pear sucker Psylla pyri, on subsequent population build up of Anthocoris nemoralis later in the season. Hereto, five large-scale trials on pear Conference were conducted. Two types of orchards were selected: the first type is surrounded by abundant vegetation from which Anthocorids easily can fly in when attracted by the presence of prey (Psylla pyri); the second type has no "reservoir" vegetation around the orchard and here it is considered that mostly the residential population of Anthocorids constitutes the predation. In all five trials positioning of thiacloprid preblossom did not prevent the normal population build up of the predatory Anthocoris sp. population later in the season. As both in orchards with surrounding vegetation and in orchards without adjacent vegetation a regular build up of the Anthocoris sp. population was observed, the outcomes of this study indicate that a preblossom application of Calypso 480 SC can be considered as "selective in time" for further Anthocoridae dynamics.
Assuntos
Heterópteros/efeitos dos fármacos , Inseticidas/toxicidade , Piridinas/toxicidade , Pyrus/parasitologia , Tiazinas/toxicidade , Animais , Larva/efeitos dos fármacos , Neonicotinoides , Controle Biológico de Vetores , Fatores de TempoRESUMO
Pear psylla, Cacopsylla pyricola (Förster) (Hemiptera: Psyllidae), a major economic pest of pears, uses a female-produced sex attractant pheromone. We compared the chemical profiles obtained from cuticular extracts of diapausing and post-diapause winterform males and females to isolate and identify the pheromone. Post-diapause females produced significantly more of the cuticular hydrocarbon, 13-methylheptacosane, than post-diapause males and diapausing females. In olfactometer assays, conspecific males were attracted to synthetic racemic 13-methylheptacosane, whereas females were not, indicating that the behavioral response to this chemical is sex-specific. Furthermore, 13-methylheptacosane was as attractive to males as a cuticular extract of females, suggesting that this chemical was largely responsible for the female attractiveness. A field study showed that males but not females were attracted to 13-methylheptacosane, confirming the olfactometer results. This study provides evidence that 13-methylheptacosane is a sex attractant pheromone for C. pyricola winterform males. This is the first identification of a sex pheromone in the Psylloidea. Our results open the path to developing monitoring tools and possibly new strategies for integrated pest management of this insect.
Assuntos
Hemípteros/química , Pyrus/parasitologia , Atrativos Sexuais/química , Animais , Feminino , Cromatografia Gasosa-Espectrometria de Massas , Hemípteros/metabolismo , Masculino , Atrativos Sexuais/isolamento & purificação , Atrativos Sexuais/metabolismoRESUMO
Dysaphis pyri is an important aphid pest of European pear (Pyrus communis) cultivars, none of which are currently reported to be resistant. In this study, we produced a progeny of the European pear Comice crossed with an accession of snow pear (Pyrus nivalis) that segregated for resistance to D. pyri in a Mendelian fashion, indicating the presence of a major gene, Dp-1. Following screening of the parents and seedlings with microsatellite markers, cosegregation analysis indicated that Dp-1 is flanked by NH006b and NH014a on linkage group 17, 2.3 and 3.6 cM away, respectively. Evidence is also presented for the duplication of linkage groups 9 and 17, which is a consequence of the allopolyploid origin of pear.
Assuntos
Afídeos , Imunidade Inata/genética , Repetições de Microssatélites/genética , Doenças das Plantas/genética , Pyrus/genética , Região 3'-Flanqueadora/genética , Região 5'-Flanqueadora/genética , Animais , Mapeamento Cromossômico , Cromossomos de Plantas , Genes de Plantas/fisiologia , Interações Hospedeiro-Parasita/genética , Pyrus/parasitologiaRESUMO
The occurrence of pear decline, a disease found in some pear (Pyrus spp.) orchards of Taiwan in recent years, is accompanied by an outbreak of Cacopsylla chinensis (Yang & Li). Two major morphological forms (summer and winter forms) with a variety of intermediate body color and two phylogenetic lineages of this psyllid have been described. The work herein used sequences of mitochondrial cytochrome oxidase I (COI) and 16S rDNA regions to delineate the genetic differentiation of this color-variable insect and to elucidate their relationship. Sequence divergence and phylogenetic analysis have shown that C. chinensis individuals could be divided into two lineages with 3.3 and 2.3% divergence of COI and 16S rDNA, respectively. All specimens from China were found to belong to lineage I. Restriction fragment length polymorphism analysis of COI with restriction enzymes AcuI, AseI, BccI, and FokI on 263 specimens of six populations from Taiwan produced two digestion patterns, which are in agreement with the two lineages described above. Both patterns could be found in each population, with most individuals belonging to lineage I and 5-21% of the individuals belonging to lineage II. Because these two lineages included summer as well as winter morphological forms, the lineage differentiation is apparently not related to morphological characters of this psyllid. Because the invasive records are not in favor of a sympatric differentiation, this psyllid is more likely introduced as different populations from countries in temperate regions.
Assuntos
DNA Mitocondrial/química , Complexo IV da Cadeia de Transporte de Elétrons/genética , Hemípteros/genética , RNA Ribossômico 16S/genética , Animais , Hemípteros/química , Filogenia , Reação em Cadeia da Polimerase , Polimorfismo de Fragmento de Restrição , Pyrus/parasitologia , Estações do Ano , TaiwanRESUMO
The molecular interaction between pear tree (Pyrus spp.) and the phloem-feeding psylla Cacopsylla pyri (Linnaeus) was investigated through the construction and characterization of cDNA subtracted libraries. Genes expressed upon insect infestation were identified in the susceptible pear cultivar Bartlett and in the resistant selection NY10355. In both interactions, genes involved in the plant defense response were induced, confirming the observed similarity between the response to pathogens and to insects with piercing/sucking mouthparts. However, the two expression profiles were found to be different, with more genes involved in the response to biotic and abiotic stress being activated in the resistant plant than in the susceptible one. Further characterization of the identified genes could lead to the development of molecular markers associated with tolerance/resistance to pear psylla.