ABSTRACT
Abstract Chrysodeixis includens has become the major Lepidopteran pest of soybean crops, especially in the Brazilian Cerrado (savanna) region. A native isolate of Chrysodeixis includens nucleopolyhedrovirus (ChinNPV) from this region, Buritis, MG, was assessed for its biological and molecular features. In addition, in vitro co-infection with Anticarsia gemmatalis multiple nucleopolyhedrovirus (AgMNPV), another virus of an important soybean pest, was tested. The ChinNPV-Buritis isolate presented an average LC50 of 7,750 occlusion bodies (OBs)/ml of diet in C. includens larvae. Analysis of restriction endonuclease profiles of viral DNA revealed similarities with previously described ChinNPV isolates IE, IF, and IG from Brazil, although the presence of submolar bands indicates genetic heterogeneity. Optical microscopy analysis in conjunction with quantitative PCR (qPCR) demonstrated in vitro infection of this isolate in IPLB-SF-21AE, Sf9, and BTI-Tn-5B1-4 cell lines, but the amount of ChinNPV tends to decrease through serial passages. The qPCR method developed in this study successfully detected both AgMNPV and ChinNPV from cell culture and from infected larvae. The cell line Tn-5B1-4 is indicated for future development of in vitro production and co-infection studies.
Subject(s)
Bombyx , Nucleopolyhedroviruses , Biological Control Agents , LarvaABSTRACT
Apple plants from France introduced in Brazil for research purposes were subjected to a phytosanitary analysis at the Plant Quarantine Laboratory of Embrapa Genetic Resources and Biotechnology (Cenargen). After grafting onto healthy apple rootstock, some plants showed phytoplasma-infection symptoms. Polymerase Chain Reaction (PCR) tests yielded DNA fragments of the expected size for phytoplasmas. DNA sequencing revealed an identity of the 16S rDNA nucleotide sequence of 98-99% with 'Candidatus Phytoplasma solani'. This phytoplasma species is responsible for losses in European apple orchards and has not been reported in Brazil. According to the Federal Legislation on Plant Protection, the plants were incinerated to avoid the introduction of this exotic pest in Brazil.(AU)
Plantas de macieira originárias da França introduzidas no Brasil para fins de pesquisa foram submetidas à análise no Laboratório de Quarentena Vegetal da Embrapa Recursos Genéticos e Biotecnologia (Cenargen). Após realizar a enxertia em porta-enxertos sadios, algumas plantas apresentaram sintomas típicos de infecção por fitoplasmas. Os testes por meio da técnica de reação em cadeia da polimerase (PCR) obtiveram fragmentos de DNA do tamanho esperado para fitoplasmas. O sequenciamento de DNA revelou uma identidade de 98-99% da região 16 rDNA dos fitoplasmas encontrados com o fitoplasma 'Candidatus Phytoplasma solani'. Essa espécie de fitoplasma é responsável por perdas em pomares de maçã europeus e não foi relatada no Brasil. De acordo com a Legislação Federal de Proteção de Plantas, as plantas de macieira foram incineradas para evitar a entrada dessa praga exótica no Brasil.(AU)