-
[show abstract]
[hide abstract]
ABSTRACT: Shallot virus X (ShVX), a type species in the genus Allexivirus of the family Alfaflexiviridae has been associated with shallot plants in India and other shallot growing countries like Russia, Germany, Netherland, and New Zealand. Coat protein (CP) and nucleic acid binding protein (NB) region of the virus was obtained by reverse transcriptase polymerase chain reaction from scales leaves of shallot bulbs. The partial cDNA contained two open reading frames encoding proteins of molecular weights of 28.66 and 14.18 kDa belonging to Flexi_CP super-family and viral NB super-family, respectively. The percent identity and phylogenetic analysis of amino acid sequences of CP and NB region of the virus associated with shallot indicated that it was a distinct isolate of ShVX.
Indian Journal of Virology 06/2011; 22(1):63-5. · 0.28 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Reduced seed production in onion is associated with Onion yellow dwarf virus (OYDV), a filamentous Potyvirus. Onion is also infected with other filamentous virus particles suspected to be Allexivirus. RT-PCR was used to detect mixed infection of both the viruses in leaves and bulbs. A duplex RT-PCR was developed, which simultaneously detected the presence of these two viruses in winter (Rabi) onion bulb. In summer (Kharif) onion bulbs only Allexivirus was detected. The absence of OYDV in summer crop is discussed. The sequencing of RT-PCR amplified products confirmed the identity of OYDV and Allexivirus, the latter showing closer identity to Garlic virus C (GVC)/Garlic mite-borne mosaic virus. This makes the first detection of an Allexivirus in onion crop in India. The duplex RT-PCR to detect these viruses (OYDV and Allexivirus) would be an improvement for indexing of viruses in onion bulbs for seed production.
Indian Journal of Virology 06/2010; 21(1):64-8. · 0.28 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Citrus yellow mosaic virus (CYMV), a non-enveloped bacilliform DNA virus causes a severe mosaic disease in sweet oranges in India. CYMV is weakly immunogenic, thus serodiagnosis is not a preferred method for its detection. As an alternative a rapid and reliable detection protocol by polymerase chain reaction (PCR) was developed. However, high levels of polyphenolics and tannins in citrus leaves generally interfered with obtaining good quality DNA, and thus affected the reliable detection of virus by PCR. Consequently, we evaluated the addition of sodium sulphite to a DNA extraction protocol used previously and compared the two methods with a commercially available plant DNeasy Kit (Qiagen). The addition of sodium sulphite improved the yield, quality and stability of DNA. The CYMV DNA was not only amplified at lower template DNA concentration, but also provided better DNA yields. In addition, the sodium sulphite extracted DNA survived at various temperatures much longer than those extracted without addition of sodium sulphite or with the commercial kit. The amplified product of CYMV DNA was cloned, sequenced and found to have 89% sequence identity with the only other sequenced Indian isolate of CYMV.
Journal of Virological Methods 10/2003; 112(1-2):153-6. · 2.01 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Citrus yellow mosaic virus (CYMV), a non-enveloped bacilliform DNA virus causes a severe mosaic disease in sweet oranges in India. CYMV is weakly immunogenic, thus serodiagnosis is not a preferred method for its detection. As an alternative a rapid and reliable detection protocol by polymerase chain reaction (PCR) was developed. However, high levels of polyphenolics and tannins in citrus leaves generally interfered with obtaining good quality DNA, and thus affected the reliable detection of virus by PCR. Consequently, we evaluated the addition of sodium sulphite to a DNA extraction protocol used previously and compared the two methods with a commercially available plant DNeasy Kit (Qiagen). The addition of sodium sulphite improved the yield, quality and stability of DNA. The CYMV DNA was not only amplified at lower template DNA concentration, but also provided better DNA yields. In addition, the sodium sulphite extracted DNA survived at various temperatures much longer than those extracted without addition of sodium sulphite or with the commercial kit. The amplified product of CYMV DNA was cloned, sequenced and found to have 89% sequence identity with the only other sequenced Indian isolate of CYMV.
Journal of Virological Methods.
-
[show abstract]
[hide abstract]
ABSTRACT: SUMMARY A duplex RT-PCR was standardized for the simulta- neous detection of Onion yellow dwarf virus (OYDV) and Garlic latent virus (GarLV), a synonym for the rec- ognized species Shallot latent virus (SLV) in garlic, which allowed the successful identification of both viruses in cloves and leaves. The titre of OYDV was higher both in leaves and bulbs compared with SLV. In the leaves, OYDV was detected up to an RNA dilution of 10 -4 while SLV could be detected up to an RNA dilu- tion of 10 -3 . Duplex RT-PCR detected both viruses in ten commercial garlic cultivars. The procedure is cost- effective and sensitive and will be highly useful in quar- antine and certification programmes.
