|Novelli, V. M.|
|Mineiro, J. L. C.|
|Machado, M. A.|
Submitted to: Experimental and Applied Acarology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/5/2008
Publication Date: 8/1/2008
Citation: Novelli, V., Freitas-Astua, J., Segatti, N., Mineiro, J., Arthur, V., Bastaniel, M., Hilf, M.E., Gottwald, T.R., Machado, M. 2008. Effects of radiation (Cobalt-60) on the elimination of Brevipalpus phoenicis (Acari: Tenuipalpidae) Cardinum endosymbiont. Experimental and Applied Acarology. DOI 10.1007/s10493-008-9176-4. Interpretive Summary: Citrus leprosis virus causes leprosis, a destructive disease of citrus found primarily in Brazil. The virus is vectored by mites. The mites contain bacteria (endosymbionts) that live in various tissues in their bodies and which are passed to the offspring through the eggs. In some mites these bacteria influence whether the mite progeny will be male or female and whether the mite will act as a virus vector. This work describes irradiation of mites to remove the bacteria from the mites so comparison of vector capability can be compared between mites with bacteria and mites without bacteria.
Technical Abstract: Brevipalpus phoenicis (Geijskes) (Acari: Tenuipalpidae) is a polyphagous mite with worldwide distribution and it is also a vector of several plant viruses. In citrus, B. phoenicis transmits Citrus leprosis virus (CiLV), the causal agent of leprosis, a disease that costs millions of dollars/year for its prevention and control. B. phoenicis mites reproduce through thelytokous, producing haploid females. This characteristic is attributable to the presence of an endosymbiont bacterium of the Cardinium genus; however, very little is known about the biological and ecological implications of the presence of this endosymbiont in Brevipalpus mites. Our group investigates the role of Cardinium in the transmission of CiLV to citrus plants and hence, our goal was to eliminate the bacterium from the mite to future analyze its role in virus transmission. We assessed the effectiveness of different doses of radiation from a Cobalt-60 source to cure Cardinium sp. from B. phoenicis populations. The efficiency of irradiation on the elimination of the endosymbiont was determined by counting the number of females and males obtained in the F1 generation after irradiation and confirming the presence of the endosymbiont by PCR. Both radiation treatments influenced the oviposition period and the number of eggs laid by irradiated females. Also, irradiation eliminated the Cardinium endosymbiont and increased the number of males in progeny of the exposed populations. Although macroscopic morphological variations were not observed among the treated mites, the mortality was higher compared to the non-irradiated control group.