RESUMO
The European lantern fly Dictyophara europaea (Linnaeus, 1767), is a polyphagous dictyopharid planthopper of Auchenorrhyncha commonly found throughout the Palaearctic. Despite abundant data on its distribution range and reports on its role in the epidemiology of plant-pathogenic phytoplasmas (Flavescence dorée, FD-C), literature regarding the biology and host plants of this species is scarce. Therefore, the aims of our study were to investigate the seasonal occurrence, host plant associations, oviposition behaviour and immature stages of this widespread planthopper of economic importance. We performed a 3-year field study to observe the spatio-temporal distribution and feeding sources of D. europaea. The insects's reproductive strategy, nymphal molting and behaviour were observed under semi-field cage conditions. Measurement of the nymphal vertex length was used to determine the number of instars, and the combination of these data with body length, number of pronotal rows of sensory pits and body colour pattern enabled the discrimination of each instar. We provide data showing that D. europaea has five instars with one generation per year and that it overwinters in the egg stage. Furthermore, our study confirmed highly polyphagous feeding nature of D. europaea, for all instars and adults, as well as adult horizontal movement during the vegetation growing season to the temporarily preferred feeding plants where they aggregate during dry season. We found D. europaea adult aggregation in late summer on Clematis vitalba L. (Ranunculaceae), a reservoir plant of FD-C phytoplasma strain; however, this appears to be a consequence of forced migration due to drying of herbaceous vegetation rather than to a high preference of C. vitalba as a feeding plant. Detailed oviposition behaviour and a summary of the key discriminatory characteristics of the five instars are provided. Emphasis is placed on the economic importance of D. europaea because of its involvement in epidemiological cycles of phytoplasma-induced plant diseases.
Assuntos
Cadeia Alimentar , Hemípteros/fisiologia , Oviposição , Phytoplasma/fisiologia , Doenças das Plantas/microbiologia , Vitis , Animais , Feminino , Hemípteros/anatomia & histologia , Hemípteros/crescimento & desenvolvimento , Masculino , Ninfa/anatomia & histologia , Ninfa/crescimento & desenvolvimento , Ninfa/fisiologia , Dinâmica Populacional , Estações do Ano , Sérvia , Vitis/crescimento & desenvolvimento , Vitis/microbiologiaRESUMO
Eriophyoids are an ancient group of highly miniaturized, morphologically simplified and diverse phytoparasitic mites. Their possible numerous host-switch events have been accompanied by considerable homoplastic evolution. Although several morphological cladistic and molecular phylogenetic studies attempted to reconstruct phylogeny of Eriophyoidea, the major lineages of eriophyoids, as well as the evolutionary relationships between them, are still poorly understood. New phylogenetically informative data have been provided by the recent discovery of the early derivative pentasetacine genus Loboquintus, and observations on the eriophyoid reproductive anatomy. Herein, we use COI and D1-2 rRNA data of 73 eriophyoid species (including early derivative pentasetacines) from Europe, the Americas and South Africa to reconstruct part of the phylogeny of the superfamily, and infer on the basal divergence of eriophyoid taxa. In addition, a comparative CLSM study of the female internal genitalia was undertaken in order to find putative apomorphies, which can be used to improve the taxonomy of Eriophyoidea. The following molecular clades, marked by differences in genital anatomy and prodorsal shield setation, were found in our analyses: Loboquintus(Pentasetacus((Eriophyidae + Diptilomiopidae)(Phytoptidae-1, Phytoptidae-2))). The results of this study suggest that the superfamily Eriophyoidea comprises basal paraphyletic pentasetacines (Loboquintus and Pentasetacus), and two large monophyletic groups: Eriophyidae s.l. [containing paraphyletic Eriophyidae sensu Amrine et al. 2003 (=Eriophyidae s.str.) and Diptilomiopidae sensu Amrine et al. 2003] and Phytoptidae s.l. [containing monophyletic Phytoptidae sensu Boczek et al. 1989 (=Phytoptidae s.str.) and Nalepellidae sensu Boczek et al. 1989]. Putative morphological apomorphies (including genital and gnathosomal characters) supporting the clades revealed in molecular analyses are briefly discussed.
Assuntos
Ácaros/classificação , Filogenia , Animais , Proteínas de Artrópodes/genética , Proteínas de Artrópodes/metabolismo , Evolução Biológica , Complexo IV da Cadeia de Transporte de Elétrons/genética , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Genitália/ultraestrutura , Microscopia Confocal , Ácaros/genética , Ácaros/ultraestrutura , RNA Ribossômico 28S/genética , RNA Ribossômico 28S/metabolismoRESUMO
Alder yellows phytoplasma (AldYp) is classified as a member of the 16SrV-group of phytoplasmas and is closely related to Flavescence dorée (FD), a quarantined pathogen of economic importance affecting vineyards across Europe. AldYp is associated with common (Alnus glutinosa) and grey alder (A. incana), and has been reported in France, Italy, Germany, Austria, Switzerland, the Baltic region, Serbia, and Montenegro (1,2,4). For Macedonian vineyards, so far, neither infection of grapevine with 16SrV-group of phytoplasmas nor the presence of the main FD phytoplasma vector, Scaphoideus titanus, has been recorded. However, the presence of FD-related phytoplasma was detected in wild Clematis vitalba. In September and October 2013, leaves with petioles from A. glutinosa exhibiting leaf discoloration and yellowing were collected from two sites (41°23'43â³ N, 22°54' E and 41°23' N, 22°53' E) in southeast Macedonia near the village of Smolare (Strumica district). Eight samples were collected from each site. Leaves of six asymptomatic alder seedlings collected from the same sites served as a control. Nucleic acids were extracted from fresh leaf midribs and petioles using a DNeasy Plant Mini Kit (Qiagen, Hilden, Germany). Initial phytoplasma identification was carried out by nested PCR assay of the 16S rRNA gene, using universal primers P1/P7 and R16F2n/R16R2 followed by RFLP with MseI endonuclease (Fermentas, Vilnius, Lithuania), as previously reported (4). Characterization of detected phytoplasmas was performed by amplifying two genetic loci specific for the members of the 16SrV group phytoplasmas; the ribosomal protein gene operon (rp) using primers rp(V)F1/rpR1 and rp(V)F1A/rp(V)R1A (3), and the non-ribosomal metionine aminopeptidase (map) gene using primer set FD9f5/MAPr1 and FD9f6/MAPr2 (1). The PCR amplicons were sequenced and deposited in NCBI GenBank database under the accession numbers KJ605448 to 52 (map) and KJ605453 to 57 (rp). The obtained sequences were compared with reference sequences of the 16SrV-group phytoplasmas (1,3) using the neighbor-joining method in MEGA5 (5). The presence of phytoplasma was detected in 14 of 16 symptomatic alder samples, while all control plants tested negative. The MseI restriction profiles were identical among all 14 samples and with the reference strains of the 16SrV group phytoplasmas (EY1 - 16SrV-A, FD-C - 16SrV-C, and FD-D - 16SrV-D). The rp-based phylogeny enabled identification of four diverse phytoplasma strains among the AldYp strains from Macedonia. Three strains clustered within the rpV-E subgroup while one belonged to rpV-L subgroup. Phylogenetic analysis of the more variable genetic locus, map, showed the presence of five diverse phytoplasma strains. Four strains belonged to the map-FD2 (FD-D, FD92) cluster, while one grouped within the map-FD1 (FD70) cluster. To our knowledge, this is the first report of 16SrV phytoplasma group occurrence on alder in Macedonia. The significant similarity between AldYp strains and FD sensu stricto indicate the risk of pathogen exchange between the wild ecosystem and the grapevine (1). Alder trees naturally infected with the FDp-related strains could therefore represent a serious risk for FD outbreak in Macedonian vineyards if local S. titanus populations developed. References: (1) G. Arnaud et al. Appl. Environ. Microbiol. 73:4001, 2007. (2) T. Cvrkovic et al. Plant Pathol. 57:773, 2008. (3) M. Martini et al. Int. J. Syst. Evol. Microbiol. 57:2037, 2007. (4) S. Radonjic et al. Plant Dis. 97:686, 2013. (5) K. Tamura et al. Mol. Biol. Evol. 28:2731, 2011.
RESUMO
Alder yellows phytoplasmas (AldYp) of the 16SrV-group associated with common alder (Alnus glutinosa) and grey alder (A. incana) are closely related to the grapevine yellows (GY)-associated quarantine phytoplasma Flavescence dorée (FDp). AldYp have been reported in several countries where epidemic appearance of FDp has been confirmed (France, Italy, and Serbia) (1,2). To date, the presence of 16SrV-group of phytoplasmas has not been reported in Montenegro; however, the main vector of FD phytoplasma, Scaphoideus titanus, has been identified in Montenegrin vineyards since 2008. During a survey in September 2011, in the northern part of Montenegro, 12 symptomatic alder trees showing symptoms of leaf discoloration, ranging from yellow to light green, were sampled. Six samples, each comprising several symptomatic leaves, were collected from A. glutinosa at streamside in woodlands near the town Kolasin and other six samples from A. incana close to the river Lim near the town of Bijelo Polje. Leaves of six young A. glutinosa seedlings were used as controls. Total DNA was extracted from fresh leaf midribs and petioles using the DNeasy Plant Mini Kit (Qiagen, Hilden, Germany). Nested PCR assay was conducted on 16S rRNA gene using phytoplasma generic primers P1/P7 and F2n/R2 followed by RFLP with MseI endonuclease (Fermentas, Vilnius, Lithuania) (3). Confirmation of identification and characterization of phytoplasma positive samples was performed by amplifying the non-ribosomal metionine aminopeptidase (map) gene using FD9f5/MAPr1 and FD9f6/MAPr2 primer set (1), specific for the members of the 16SrV group phytoplasmas. Amplification products were sequenced and deposited in GenBank (KC188998 through 9001). Comparison of the map gene sequences was performed by phylogenetic analysis along with 20 reference sequences of the 16SrV-group members (1), using the neighbor-joining method in MEGA5 software (4). 16S rRNA gene amplification revealed the presence of phytoplasmas in 11 out of 12 symptomatic samples, while Mse I restriction analysis and comparison with reference strains (AldYp and FDp from Serbia) enabled affiliation of detected phytoplasmas to the 16SrV-group. None of the controls were positive for any phytoplasma. Phylogenetic analysis of the Montenegrin AldYp map gene sequences revealed presence of four different strains clustering within the previously defined clusters of the 16SrV-group members (1). Three different strains associated with symptomatic A. glutinosa were identified and they clustered either within the FD1, FD2, or PGY-C cluster, while a single detected strain from A. incana proved to be identical with PGY-A isolate of AldY phytoplasma infecting grapevine in Germany (AM384892). To our knowledge, this is the first report of the association of 16SrV-group phytoplasmas with common and grey alder in Montenegro, as well as the first report of FD-related phytoplasmas in Montenegro. Since alder trees are considered as a possible natural reservoir of the FD phytoplasmas (1), the finding of alders naturally infected with strains related to the FDp (FD1 and FD2 clusters) indicate a possible threat of economic importance to the grape production in Montenegro, which should be addressed in further research. References: (1) G. Arnaud et al. Appl. Environ. Microbiol. 73:4001, 2007. (2) T. Cvrkovic et al. Plant Pathol. 57:773, 2008. (3) I-M. Lee et al. Int. J. Syst. Evol. Bacteriol. 48:1153, 1998. (4) K. Tamura et al. Mol. Biol. Evol. 28:2731, 2011.
RESUMO
Maize redness (MR), induced by stolbur phytoplasma ('Candidatus Phytoplasma solani', subgroup 16SrXII-A), is characterized by midrib, leaf, and stalk reddening and abnormal ear development. MR has been reported from Serbia, Romania, and Bulgaria for 50 years, and recent epiphytotics reduced yields by 40 to 90% in South Banat District, Serbia. Potential vectors including leafhoppers and planthoppers in the order Hemiptera, suborder Auchenorrhyncha, were surveyed in MR-affected and low-MR-incidence fields, and 33 different species were identified. Only Reptalus panzeri populations displayed characteristics of a major MR vector. More R. panzeri individuals were present in MR-affected versus low-MR fields, higher populations were observed in maize plots than in field border areas, and peak population levels preceded the appearance of MR in late July. Stolbur phytoplasma was detected in 17% of R. panzeri adults using nested polymerase chain reaction but not in any other insects tested. Higher populations of R. panzeri nymphs were found on maize, Johnsongrass (Sorghum halepense), and wheat (Triticum aestivum) roots. Stolbur phytoplasma was detected in roots of these three plant species, as well as in R. panzeri L(3) and L(5) nymphs. When stolbur phytoplasma-infected R. panzeri L(3) nymphs were introduced into insect-free mesh cages containing healthy maize and wheat plants, 89 and 7%, respectively, became infected. These results suggest that the MR disease cycle in South Banat involves mid-July transmission of stolbur phytoplasma to maize by infected adult R. panzeri. The adult R. panzeri lay eggs on infected maize roots, and nymphs living on these roots acquire the phytoplasma from infected maize. The nymphs overwinter on the roots of wheat planted into maize fields in the autumn, allowing emergence of phytoplasma-infected vectors the following July.