Título:	Estudos biológicos e moleculares de um isolado necrótico de bean yellow mosaic virus (BYMV), não transmitido por afídeos
Autor(es):	Mello, Raquel Neves de
Orientador(es):	Costa, Cláudio Lúcio Resende, Renato de Oliveira
Assunto:	Vírus - BYMV Afídeos Potyvirus
Data de publicação:	28-Jan-2021
Data de defesa:	1996
Referência:	MELLO, Raquel Neves de. Estudos biológicos e moleculares de um isolado necrótico de bean yellow mosaic virus (BYMV), não transmitido por afídeos. 1996. xiv, 83 f. Dissertação (Mestrado em Ecologia)—Universidade de Brasília, Brasília, 1996.
Abstract:	Bean yellow mosaic virus is a virus species identified as a member of the genus Potyvirus within the Potyviridae family. These viruses are aphid transmitted in a nonpersistent manner. The transmission depends upon both virus encoded proteins: the coat protein (CP) and the heiper component proteinase (HC-Pro). Mutational studies in some of the amino acids domains demonstrated that both proteins are related with the loss of transmission of these viruses by aphids. Mutations on the highly conserved triplet D/NAG, located at the CP N-terminal, and on KITC and PTK boxes, located at HC-Pro N-terminal and C-terminal respectively, were associated with the lack of vector transmissibility. Fifteen different species of aphids were tested for the transmission of a BYMV necrotic strain, denoted BYMVn. None of them was able to transmit this virus strain. Dependent transmission assay, using BCMV as helper virus, was also negative. Ten different inocullum sources for virus acquisition by the aphid were also tested and no virus transmission was obtained. In order to elucidate the molecular basis of this non aphid-transmissibility of the viruses, part of the N-terminal of the BYMVn coat protein was sequenced. Total RNA was extracted from plants infected with BYMVn and used as template for cDNA synthesis. This cDNA was used as template for amplification by PCR and the product (414 bp from the CP N-terminal) was cloned in the pGemT Vector and sequenced. A nucleotide sequence of 170 bases from 5’ region and 208 base from 3’ region of that fragment was obtained The triplet NAG showed to be conserved in the BYMVn coat protein and it can not be associated to inability of the virus to be aphid transmitted. Further molecular analysis of the HC-Pro may show if mutations on KITC or PTK boxes are involved on the BYMVn transmissibility by aphids. Approximately 40% of N-terminal coat protein of BYMVn was sequenced. The similarity values found may correspond to the real difference between the BYMVn CP and the other previously isolates characterize. Differences ranging from 18,3 - 29,6% of nucleotides sequences, and 12 - 25,5% at amino acids levei demonstrate that even in the some species of potyvirus, significant variations in the nucleotides and amino acids sequences can be found and it can express the biological differences observed between BYMVn and the other BYMV isolates. Analysis of the amino acid similarities and identities between BYMVn and the other isolates demonstrated that the necrotic isolate is closer related to the S strain. 65 Additional western blot studies showed that CP of BYMVn has a molecular welght of about 30 kDa, showing no changes In its serologlcal reactivlty. The HPLC peptlde profile of tryptlc dlgest CP showed that this technlque can be used to separate spoclos wlthln tho potyvirus gonus, but it doos not allow us to locnlo smoll dlfferoncos In the amino acld sequence responslble for aphid transmission.
Unidade Acadêmica:	Instituto de Ciências Biológicas (IB)
Informações adicionais:	Dissertação (mestrado)—Universidade de Brasília, Instituto de Ciências Biológicas, 1996.
Programa de pós-graduação:	Programa de Pós-Graduação em Ecologia
Aparece nas coleções:	Teses, dissertações e produtos pós-doutorado

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