Diversidade genética de Zabrotes subfasciatus Boheman (Coleoptera: Bruchidae) avaliada com marcadores ISSR

• Autor(a) principal: Souza, Giselle Anselmo de
• Data de Publicação: 2007
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/4818
• topic: Marcadores moleculares; Zabrotes subfasciatus; Bruquídeo; Molecular markers; Zabrotes subfasciatus; CNPQ::CIENCIAS BIOLOGICAS::GENETICA::GENETICA MOLECULAR E DE MICROORGANISMOS

The Zabrotes subfasciatus Boheman (Coleoptera: Bruchidae) is a species probably originated from Central America. It became an agricultural pest since it was established and continually began to reproduce in stored seeds and later diffused throughout tropical and subtropical regions. In stores, those insects cause damages to the grains, by boring them and giving them an unpleasant flavor, therefore depreciating their commercial value. In seeds, the pest consumes the reserves of the cotyledons, therefore endangering germination. This study was conducted to estimate the genetic diversity in Z. subfasciatus populations, by using the molecular markers ISSR (Inter Simple Sequence Repeat). Twelve populations of Z. subfasciatus amostradas were sampled in eight Brazilian states as totaling 269 individuals, then they were evaluate. Five primers ISSR (UBC 807, UBC 808, UBC 809, UBC 811, UBC 891) were used, whereas a total of 51 polymorphic bands averaging 10 bands by each primer were amplified. The percent polymorphism within each population ranged from 74.51 to 92.16, with an average percentage of 83.82. The expected heterozygozite corrected by Nei in 1978 ranged from 0.2253 to 0.;3281 with some 0.2885 average, whereas the genetic diversity index by Shannon and Weaver (HE) ranged from 0.2908 to 0.4805, as averaging 0.4167. At species level, those two indexes showed the values 0.3636 and 0.5393 respectively. The FST values between the population pairs obtained by molecular variance analysis (AMOVA) ranged from 0.06804 to 0.6165. The genetic distance by Nei used in estimation of the genetic divergence among populations ranged from 0.0563 to 0.3250. The AMOVA allowed for the partition of the genetic variation into two levels: either inside and among populations. Higher genetic variation was observed inside population, with 66% of the total variation. Only 34% genetic variation were observed among populations. The Mantel` test showed low correlation between geographical distance and FST, genetic identity and FST, and between the Nei´genetic distance and FST. According to the results, the following conclusions were drawn: the genetic variability of the species is still considered as low in Brazil, probably due to the recent introduction of the pest; and those Zabrotes subfasciatus populations showed to be not geographically structured in Brazil.