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Lotfali Dolatti

Bio: Lotfali Dolatti is an academic researcher from University of Tabriz. The author has contributed to research in topics: Aphis & Rhopalosiphum. The author has an hindex of 1, co-authored 1 publications receiving 133 citations.

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TL;DR: The results show cross-species application of known microsatellite loci is a highly promising source of codominant markers for population genetic and evolutionary studies in aphids.
Abstract: Despite the relative ease of isolating microsatellites, their development still requires substantial inputs of time, money and expertise For this reason there is considerable interest in using existing microsatellites on species from which markers were not cloned We tested cross-species amplification of 48 existing aphid loci in species of the following genera: Aphidinae: Aphidini: Aphis and Rhopalosiphum ; Aphidinae: Macrosiphini: Acyrthosiphum , Brevicoryne , Diuraphis , Illinoia , Macrosiphoniella , Macrosiphum , Metopeurum , Metapolophium , Myzus , Phorodon , Sitobion and Uroleucon and Neuquenaphidinae: Neuquenaphis Our results show cross-species application of known microsatellite loci is a highly promising source of codominant markers for population genetic and evolutionary studies in aphids

135 citations


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TL;DR: The pea aphid complex illustrates how ecological divergence can be sustained among many hybridizing populations and how insect host races blend into species by gradual reduction of gene flow.
Abstract: Sympatric populations of insects adapted to different host plants, i.e., host races, are good models to investigate how natural selection can promote speciation in the face of ongoing gene flow. However, host races are documented in very few model systems and their gradual evolution into good species, as assumed under a Darwinian view of species formation, lacks strong empirical support. We aim at resolving this uncertainty by investigating host specialization and gene flow among populations of the pea aphid complex, Acyrthosiphon pisum. Genetic markers and tests of host plant specificity indicate the existence of at least 11 well-distinguished sympatric populations associated with different host plants in Western Europe. Population assignment tests show variable migration and hybridization rates among sympatric populations, delineating 8 host races and 3 possible species. Notably, hybridization correlates negatively with genetic differentiation, forming a continuum of population divergence toward virtually complete speciation. The pea aphid complex thus illustrates how ecological divergence can be sustained among many hybridizing populations and how insect host races blend into species by gradual reduction of gene flow.

387 citations

Journal ArticleDOI
TL;DR: The population structure and symbiont community of the pea aphid (Acyrthosiphon pisum), which feeds on a range of legume species and is known to form genetically differentiated host‐adapted populations, is studied.
Abstract: Polyphagous insect herbivores experience different selection pressures on their various host plant species. How this affects population divergence and speciation may be influenced by the bacterial endosymbionts that many harbor. Here, we study the population structure and symbiont community of the pea aphid (Acyrthosiphon pisum), which feeds on a range of legume species and is known to form genetically differentiated host-adapted populations. Aphids were collected from eight legume genera in England and Germany. Extensive host plant associated differentiation was observed with this collection of pea aphids comprising nine genetic clusters, each of which could be associated with a specific food plant. Compared to host plant, geography contributed little to genetic differentiation. The genetic clusters were differentiated to varying degrees, but this did not correlate with their degree of divergence in host use. We surveyed the pea aphid clones for the presence of six facultative (secondary) bacterial endosymbionts and found they were nonrandomly distributed across the aphid genetic clusters and this distribution was similar in the two countries. Aphid clones on average carried 1.4 species of secondary symbiont with those associated with Lathyrus having significantly fewer. The results are interpreted in the light of the evolution of specialization and ecological speciation.

208 citations

Journal ArticleDOI
TL;DR: Comparison of cDNA libraries identified aphid genes with tissue-specific expression patterns, and gene expression that is induced by feeding on Nicotiana benthamiana, and 2423 genes that are novel to science and potentially aphid-specific were identified.
Abstract: The green peach aphid, Myzus persicae (Sulzer), is a world-wide insect pest capable of infesting more than 40 plant families, including many crop species. However, despite the significant damage inflicted by M. persicae in agricultural systems through direct feeding damage and by its ability to transmit plant viruses, limited genomic information is available for this species. Sequencing of 16 M. persicae cDNA libraries generated 26,669 expressed sequence tags (ESTs). Aphids for library construction were raised on Arabidopsis thaliana, Nicotiana benthamiana, Brassica oleracea, B. napus, and Physalis floridana (with and without Potato leafroll virus infection). The M. persicae cDNA libraries include ones made from sexual and asexual whole aphids, guts, heads, and salivary glands. In silico comparison of cDNA libraries identified aphid genes with tissue-specific expression patterns, and gene expression that is induced by feeding on Nicotiana benthamiana. Furthermore, 2423 genes that are novel to science and potentially aphid-specific were identified. Comparison of cDNA data from three aphid lineages identified single nucleotide polymorphisms that can be used as genetic markers and, in some cases, may represent functional differences in the protein products. In particular, non-conservative amino acid substitutions in a highly expressed gut protease may be of adaptive significance for M. persicae feeding on different host plants. The Agilent eArray platform was used to design an M. persicae oligonucleotide microarray representing over 10,000 unique genes. New genomic resources have been developed for M. persicae, an agriculturally important insect pest. These include previously unknown sequence data, a collection of expressed genes, molecular markers, and a DNA microarray that can be used to study aphid gene expression. These resources will help elucidate the adaptations that allow M. persicae to develop compatible interactions with its host plants, complementing ongoing work illuminating plant molecular responses to phloem-feeding insects.

135 citations

Journal ArticleDOI
TL;DR: It is hypothesized that the new availability or abundance of resources triggered a cascade of divergence events in this newly formed complex of pea aphids, implying that the pea Aphid complex ranks among the most rapid adaptive radiations yet documented.
Abstract: Adaptation to different resources has the potential to cause rapid species diversification, but few studies have been able to quantify the time scale of recent adaptive radiations. The pea aphid, Acyrthosiphon pisum, a model of speciation for host-specialized parasites, consists of several biotypes (races or species) living on distinct legume hosts. To document this radiation, we used rapidly evolving sequences from Buchnera, the maternally transmitted bacterial endosymbiont of aphids. Analyses of Buchnera pseudogene sequences revealed that 11 host-associated biotypes sort mostly into distinct matrilines despite low sequence divergence. A calibration based on divergence times of 7 sequenced genomes of Buchnera allowed us to date the last maternal ancestor of these biotypes between 8,000 and 16,000 years, with a burst of diversification at an estimated 3,600–9,500 years. The recency of this diversification, which is supported by microsatellite data, implies that the pea aphid complex ranks among the most rapid adaptive radiations yet documented. This diversification coincides with post-Pleistocene warming and with the domestication and anthropogenic range expansion of several of the legume hosts of pea aphids. Thus, we hypothesize that the new availability or abundance of resources triggered a cascade of divergence events in this newly formed complex.

98 citations

Journal ArticleDOI
TL;DR: It is found that PAUS is not responsible for causing host plant specialization in pea aphid, and examination of aphids in which PAUS presence has been naturally manipulated supports this conclusion.
Abstract: Symbioses are ubiquitous in nature. However, these interactions, in particular those which are facultative from the perspective of the host, are still poorly understood. One major question is whether facultative symbionts affect host fitness, and in particular whether they can benefit the host. In pea aphid, host plant specialization was found to be associated with the presence of Pea Aphid U-type Symbiont [Proc. R. Soc. Lond. B 270 (2003) S209]. Host and symbiont genomes are normally co-transmitted, making it difficult to determine which is responsible for causing this variation in fitness. Here antibiotic treatment is used to selectively remove the symbiont, thus partitioning symbiont and host genomes. I find that PAUS is not responsible for causing host plant specialization. Examination of aphids in which PAUS presence has been naturally manipulated also supports this conclusion. Additional work will be necessary to determine the forces maintaining this symbiont in host populations, and whether it benefits the host insect under different conditions.

93 citations