Data/hora: 01/06/2024 00:32:41

Biblioteca(s): | Embrapa Agropecuária Oeste.
Data corrente: | 25/08/2004
Data da última atualização: | 25/08/2004
Autoria: | ALMEIDA, R. P. de.
Título: | Trichogramma and its relationship with Wolbachia: identification of Trichogramma species, phylogeny, transfer and costs of Wolbachia symbionts.
Ano de publicação: | 2004
Fonte/Imprenta: | 2004.
Páginas: | 142 p.
Idioma: | Inglês
Notas: | Thesis (Doctor) - Wageningen Universiteit, Wageningen, 2004.
Conteúdo: | Identification of Trichogramma individuals has long been very difficult. No reliable character was known for the identification of species in this genus, until the utility of male genitalia was recognized in 1968, some 135 years after the first Trichogramma was described (T. evanescens Westwood, 1833). However, the presence of completely parthenogenetic lines in this species remained an identification problem because the no reliable female characters exist that allowed identification. The discovery of Wolbachia as a cause for the complete parthenogenesis in this genus has allowed the identification of such thelytokous lines. Antibiotic treatment could revertWolbachia infected thelytokous species to sexual ones, thus producing males and allowing their identification in the morphological system.  However, the lack of morphological identification of Trichogramma females was only solved with the use of molecular techniques based on rDNA sequencing of the internal transcribed spacer 2 (ITS2) region. Here, this technique was proved to be a reliable tool for the identification of T. cacoeciae, a thelytokous species where the parthenogenetic reproduction is not due to Wolbachia infection. In this thesis we report the first record of this species in Peru (Chapter 2). This species is the only elytokousTrichogramma known in which Wolbachia is not present. T. cacoeciaepresence in South America is discussed. Identification of seventeen native/introduced Trichogramma species using rDNA sequences was done. A molecular key based on restriction analysis allowed identification of the species through the size of the PCR product and the generation of the restriction patterns. Thelytoky in Trichogramma species caused by Wolbachia collected in Peru, Colombia and USA were reported (Chapter 3).Phylogenetic analysis and comparison of DNA sequences of the Wolbachiawsp gene allowed for the recognition of new Wolbachia group ?Ato? in the clade of Wolbachia that infect Trichogramma species. The construction of Wolbachiaphylogenetic tree showed four distinct groups. The similarities in the Wolbachiasequences for the studied groups suggested the possibility of horizontal transmission between Trichogramma species (Chapter 4). Natural inter- and intraspecific horizontal transfer of PI Wolbachiabetween wasps of the genus Trichogramma was shown. Wolbachiainfection in uninfected Trichogramma females was possible when infected and uninfected immature wasps shared the same host egg. On the whole, intraspecificinterspecific transfer (Chapter 5). In T. atopovirilia, Wolbachia infection did not lead to any negative effect on the walking activity, walking speed or other behaviour components studied (Chapter 6).Finally, an overview of the most important outcomes and conclusions of this thesis is presented   (Chapter 7).
Palavras-Chave: | Análise filogenética; Morfologia; Polimerase.
Thesagro: | Controle Biológico; DNA; Espécie; Inseto; Reprodução.
Categoria do assunto: | --
Registro original: | Embrapa Agropecuária Oeste (CPAO)
Exemplares: | CPAO - (22400-1) - ADP - TS - -- - T 05/04 -  - 04.00079 - DIS