RESUMO
The AV promoter expressing AV1 and AV2 genes and AC1 promoter expressing AC1 gene are present in opposite orientation in the intergenic region of Mungbean yellow mosaic India virus (MYMIV). Transient Agrobacterium-mediated delivery of putative promoter constructs into Nicotiana benthamiana and different legumes, followed by reporter gene (beta-d-glucuronidase, GUS) assay, identified the promoter region of both AC1 and AV genes that is necessary for transcriptional initiation. Transcription activator protein-independent activity of AV promoter and differential regulation of AC1 promoter are unique to MYMIV. The AV promoter is a composite core promoter having both TATA box and Initiator elements (TATA(+)Inr(+)). Many transcription factor binding sites were identified in the upstream promoter sequences of both virion and complementary sense genes, which might be used in the transcription regulation studies of the host plant as well as the virus.
Assuntos
Geminiviridae/genética , Geminiviridae/fisiologia , Nicotiana/virologia , Regiões Promotoras Genéticas , Rhizobium/genética , Fusão Gênica Artificial , Sequência de Bases , Sítios de Ligação , Expressão Gênica , Genes Reporter , Glucuronidase/análise , Glucuronidase/genética , Dados de Sequência Molecular , RNA Mensageiro/análise , RNA Viral/análise , Rhizobium/crescimento & desenvolvimento , Nicotiana/microbiologia , Transcrição GênicaRESUMO
Agroinoculations were performed with DNA A and DNA B components of Mungbean yellow mosaic India virus (MYMIV) isolates differing in their infectivity on cowpea. Exchange of genomic components of the MYMIV isolates occurred in all the leguminous species but not in cowpea. Extremely low viral DNA accumulation and atypical leaf curl symptoms produced by reassortants in cowpea suggest barriers both for replication and systemic movement despite genetic similarity.
