Diversidade genética de Tibraca limbativentris Stål (Hemiptera: Pentatomidae) de Santa Catarina e do Rio Grande do Sul, usando marcadores RAPD

Abstract

-The work was carried out to test DNA extraction protocols and to characterize populations of Tibraca limbativentris Stål, an important rice insect-pest. Insects were collected in Joinville, Rio do Oeste and Turvo, in Santa Catarina State, and Agudo, Uruguaiana, Pelotas and Palmares do Sul, in Rio Grande do Sul State, and six literature-referenced protocols, besides a new one, were tested. DNA from ten individuals of each population was extracted using the best protocol and RAPD reactions were carried out with ten initiators. The new protocol showed the best results and was used in the PCR reactions, that generated 151 polymorphic bands, allowing to access genetic differences among all the populations; no individuals from one population were clustered with individuals from another. The largest intrapopulacional similarity was found in Uruguaiana (22%), and the smallest in Palmares do Sul (50%), which was also the most divergent population in relation to the others. The Gst was 0.5215, and the Nm was 0.4588; these values refl ect the low similarity between the populations. The smallest genic fl ow was obtained when Palmares do Sul and Pelotas were included in the comparisons, in accordance with the largest divergence of these two populations in relation to the others. There was no signifi cant relation between geographic distance and genetic similarity, which can refl ect unknown model of dispersion of T. limbativentris. New studies exploring the species dispersion strategies may help to understand the insect distribution and to unveil the main factors linked to the genetic variability within and between populations.KEY WORDS: Insecta, rice stem bug, irrigated rice, molecular marker RESUMO -O trabalho objetivou testar protocolos de extração de DNA e caracterizar populações de Tibraca limbativentris, Stål, importante inseto-praga do arroz. Os insetos foram coletados em Joinville, Rio do Oeste e Turvo, em Santa Catarina, e Agudo, Uruguaiana, Pelotas e Palmares do Sul, no Rio Grande do Sul. Testaram-se seis protocolos de extração de DNA citados na literatura, e um novo protocolo adequado à espécie em questão. DNA de dez indivíduos de cada população foi extraído usando o melhor protocolo e reações de RAPD foram realizadas com dez iniciadores. O novo protocolo mostrou os melhores resultados e foi utilizado nas reações de PCR, que geraram 151 bandas polimórfi cas, permitindo acessar diferenças genéticas entre todas as populações; não ocorreram indivíduos de uma população agrupados com os de outra. A maior similaridade intrapopulacional foi encontrada em Uruguaiana (22%), e a menor em Palmares do Sul (50%), também a população mais divergente das demais. O valor Gst foi 0,5215, e de Nm 0,4588; esses valores refl etem a pouca similaridade entre as populações. O menor Nm foi apresentado quando Palmares do Sul e Pelotas foram incluídos nas comparações, em consonância com a maior divergência apresentada por essas populações em relação às outras. Não se observou relação entre a distância geográfi ca e a similaridade ...

Genetic polymorphism, molecular characterization and relatedness of Macrobrachium species (Palaemonidae) based on RAPD-PCR

“…As important characteristics, such markers must be exclusive to the species in question and preferentially monomorphic, that is, found with 100% frequency among the individuals analyzed (Castiglioni and de Campos Bicudo, 2005;Rampelotti et al, 2008;Rahman et al, 2009).…”

Genetic variability of Dactylopius opuntiae (Homiptera, Dactylopiidae) on forage cactus in northeast Brazil

“…Silva et al (2009) reported high polymorphism (89.2%) of B. tabaci populations in okra, beans, and chili, as well as high genetic similarity (80.76 and 44%) tested with 12 RAPD primers. Rampelotti et al (2008) detected in populations of the bug-of-thatched rice, Tibraca limbativentris Stal (Hemiptera: Pentatomidae), a high level of polymorphism (98%) with the primer OPA 04, considered the most polymorphic.…”

GENETIC VARIATION OF LEAFHOPPER, Nephotettix virescens DISTANT ACTIVE TRANSMITTERS FROM ENDEMIC AND NON ENDEMIC AREAS OF RICE TUNGRO DISEASE BASED ON RAPD MARKER

“…DNA bands profile of N. virescens active transmitter from endemic and non endemic were coded binary by visual criteria of presence (1) and absence (0) band for each fragment sizes found in different primary, but only strong and consistent bands considered. The banding pattern allowed us to calculate the similarity index of Jaccard (Hidayat et al, 1996;Rampelotti et al, 2008). The procedures were performed using the program NTSYS (version 2.1).…”

“…According to Brooker (1999), gene expressions were not always different in morphology, but may also different in the molecular-product or physiological properties. The Randomly Amplified Polymorphic DNA-Polymerase Chain Reaction (RAPD-PCR) is a technique commonly used in studies of genetic variation within or between geographic populations (Naber et al, 2000;Margaritopoulos et al, 2000;Rampelotti et al, 2008). However, studies on molecular tagging conferring N. virescens from endemic and non endemic tungro disease were limited and lack information on the character of DNA.…”