Diversidade genética de Diaphorina citri Kuwayama, 1908 (Hemiptera: Psyllidae) e caracterização molecular das linhagens de Wolbachia associadas / Genetic diversity of Diaphorina citri Kuwayama, 1908 (Hemiptera: Psyllidae) and molecular characterization of the associate strains of Wolbachia

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

24/01/2012

RESUMO

Diaphorina citri Kuwayama, 1908 (Hemiptera: Psyllidae) is an exotic insect in Brazil, first recorded in the 40s. Although it causes direct damage, D. citri only received attention as a pest in 2004, when the \"Huanglonbing\" (HLB) disease was confirmed infecting citrus in Brazil, and subsequently related to D. citri as vector. Currently, there is no cure for diseased plants, and the management of HLB is based on the removal of infected trees and psyllid control, which is based on classical biological control, natural predation and chemical control. However, the continuous use of pesticides is always problematic due to the imbalance it can cause in agrosystems. Therefore, investigations on the populations structure of D. citri in Brazil and possible alternative measures for vector/disease control or management are highly desired. Thus, this study was aimed to i) evaluate the intra and interpopulation genetic diversity of D. citri and verify the existence of population structuring in Brazil, especially in the main citrus producing region of the country, ii) determine the natural rate of infection and characterize the Wolbachia strains associated with different populations of D. citri and iii) investigate the relationship among host haplotypes and the strains of Wolbachia, in order to provide data for the alternative control of this vector. The analysis of genetic diversity was done using the cytochrome oxidase I (COI) gene as a molecular marker. The fixation rates F calculated indicated the presence of genetic structure, while the molecular diversity indices pointed to a recent population expansion of D. citri in Brazil. The multilocus sequence typing analysis (\"multilocus sequencing typing - MLST\") for Wolbachia demonstrated the presence of five new sequence-types (STs = 173, 174, 175, 225 and 236), while only four were identified when using the wsp sequences as markers. The ST-173 was the predominant ST associated with D. citri, being present in all populations, while others were specific to certain populations. Analysis of the hostsymbiont relationship did not reveal the existence of specific interactions between host haplotypes and the STs of Wolbachia, or the decrease of nucleotide diversity of D. citri in populations infected by more than one ST. The effects of Wolbachia diversity on the host bioecology are still unknown, but the fact that Wolbachia is fixed in all populations and that there is a ST broadly distributed throughout the D. citri populations highlights the use of Wolbachia for the development of alternative strategies to control D. citri.

ASSUNTO(S)

bacteria bactérias diversidade genética dna mitocondrial genetic diversity genética de populações insetos vetores mitochondrial dna population genetics simbiose. symbiosis vector insects

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