Analysis of in vitro Translation of Bean Yellow Mosaic Virus RNA: Inhibition of Proteolytic Processing by Antiserum to the 49K Nuclear Inclusion Protein

In vitro translation of bean yellow mosaic virus (BYMV) RNA in rabbit reticulocyte lysate without dithiothreitol (DTT) resulted in the accumulation of high M r products. These were readily processed to low M r mature proteins after the addition of DTT followed by a 2 h incubation. Immunoprecipitation analyses of the partially processed high M r products with antisera to the 49K and 54K nuclear inclusion (NI) proteins, cylindrical inclusion (CI) protein, tobacco vein mottling virus helper component (HC) protein and capsid protein (CP) resolved the following BYMV RNA genome map: 5′ end, 32K unidentified protein, 48K HC, 42K unidentified protein, 73K CI, 49K NI, 54K NI, 32K CP, 3′ end. The addition of the 49K NI protein antiserum inhibited the proteolytic processing of the high M r translation products. The inhibition of processing was diminished by diluting the 49K NI antiserum or by adding purified 49K NI protein. Preimmune serum or the antisera to the 54K NI, CI and capsid proteins were not as effective in inhibiting the proteolytic processing. These results provide evidence that the 49K NI protein or a related protein may have a protease function in the processing of the potyvirus polyproteins

Detección del virus del mosaico amarillo dorado en líneas de habichuela y en la maleza común de las leguminosas Macroptilium lathy mides en Puerto Rico.

Bean golden yellow mosaic virus (BGYMV) is a geminivirus transmitted by whiteflies (Genus: Bemisia). This virus causes significant fosses in common bean (Phaseolus vulgaris L.). Serological techniques such as enzymelinked immunosorbent assay (ELISA) have been widely used for detection of viruses. We evaluated existing monoclonal antibodies (3F7,2G5 and 5C5) for the detection of BGYMV isolates in bean fines in Puerto Rico. Monoclonal antibody 3F7 was the most effective in detecting the virus in tissues of line DOR 364 and susceptible cuftivars Top Crop and Quest. However, it was not effective in the detection of BGYMV in lines of DOR 303, which showed typical symptoms. Sampfes from Macroptilium lathyroides, a weed that might be a possible reservoir of the virus, were also tested for viraf infection. ELISA tests were inconclusive for detection of geminiviruses in M. lathyroides. Polymerase Chain Reaction (PCR) was also used to complement BGYMV diagnosis in M. lathyroides and in bean lines that showed symptoms but were negative for the ELfSA test. Two sets of primers, specific for Begomovirus such as BGYMV, were used in PCR experiments. Using PCR, we were able to detect the virus in the line DOR 303 and in M. lathyroides tissues.El virus del mosaico dorado amarillo de la habichuela (BGYMV) es un geminivirus transmitido por moscas blancas (Género: Bemisia). Este virus causa pérdidas económicas considerables en la habichuela común (Phaseolus vulgaris L.), Las técnicas serológicas como ELISA, se han utilizado ampliamente en la detección de viruses. Se evaluaron tres anticuerpos monoclonales existentes (3F7, 2G5 y 5C5) en la detección del BGYMV en varias líneas de habichuela en Puerto Rico. El anticuerpo monoclonal 3F7 resultó el más efectivo en detectar el virus en tejidos de habichuela de la línea DOR 364 y los cultivares susceptibles Top Crop y Quest. Sin embargo, no fue efectivo en detectar el virus en la línea DOR 303 aún en presencia de síntomas típicos.También se evaluaron muestras de Macroptilium lathyroides, una maleza que puede ser reservorio del virus. Las pruebas de ELISA resultaron inconclusas en la detección de geminiviruses en M. lathyroides. Se utilizó la reacción en cadena de la poíimerasa (PCR) para complementar el diagnóstico de! BGYMV en M. lathyroides y líneas de habichuela con síntomas de virosis pero negativas a la prueba de ELISA. Se utilizaron tíos pares de iniciadores en las pruebas de PCR, específicos para Begomovirus como el BGYMV. Utilizando PCR fue posible detectar el virus en los tejidos de la línea DOR 303 y en M. lathyroides