Sek-Man Wong

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A protoplast isolation protocol was developed for kenaf (Hibiscus cannabinus L.) leaf tissue from potted plants. The kenaf protoplast system was further established to support replication of Hibiscus chlorotic ringspot virus (HCRSV). Kenaf protoplasts were isolated using 0.8% cellulase and 0.5% macerase digestion for 16 h at 25°C. Average yields ranged from(More)
Defective (D) RNAs were generated in tobacco upon passage of two isolates of Cucumber mosaic virus (CMV) initially derived from RNA transcripts of cDNA clones. In both cases, the D RNA was derived by a single in-frame deletion of either 339 or 411 nt within the 3a gene of Fny-CMV RNA 3 or M-CMV RNA 3, respectively. The generation of D RNAs was rare and(More)
The use of internal ribosome entry sites (IRESs) is one of the unorthodox mechanisms exploited by viruses to initiate the translation of internal genes. Herein, we report a plant virus exploiting an IRES and its 3'-untranslated region (UTR) to express its internal genes, notably the 3'-proximal viral coat protein gene. Hibiscus chlorotic ringspot virus(More)
RNA plant viruses use various translational regulatory mechanisms to control their gene expression. Translational enhancement of viral mRNAs that leads to higher levels of protein synthesis from specific genes may be essential for the virus to successfully compete for cellular translational machinery. The control elements have yet to be analyzed for members(More)
Salicylic acid (SA)-induced resistance to Cucumber mosaic virus (CMV) in tobacco (Nicotiana tabacum) results from inhibition of systemic virus movement and is induced via a signal transduction pathway that also can be triggered by antimycin A, an inducer of the mitochondrial enzyme alternative oxidase (AOX). In Arabidopsis thaliana, inhibition of CMV(More)
Viral nervous necrosis disease (VNN), caused by nervous necrosis virus (NNV), leads to mass mortality in mariculture. However, phenotypic selection for resistance against VNN is very difficult. To facilitate marker-assisted selection (MAS) for resistance against VNN and understanding of the genetic architecture underlying the resistance against this(More)
Hibiscus chlorotic ringspot virus (HCRSV) from naturally infected Hibiscus rosa-sinensis L. loses virulence in its experimental systemic host Hibiscus cannabinus L. (kenaf) after serial passages in a local lesion host Chenopodium quinoa. Here we report the genetic changes responsible for the loss of virulence at the molecular level. A remarkable covariation(More)
The nucleotide sequence of the coat protein gene of cymbidium mosaic virus (CyMV) has been determined from a cDNA clone that encompassed the 3′-region of the virus genome. The 0.75 kb coat protein open reading frame (ORF) codes for a 24kD polypeptide. The coat protein coding region was separated from the 3′-poly(A) terminal of the viral genome by an 80 base(More)
Post-transcriptional gene silencing (PTGS) and virus-encoded gene-silencing suppressors are defence and counterdefence strategies developed by host and pathogens during evolution. Using a green fluorescence protein-based transient suppression system, the coat protein (CP) of Hibiscus chlorotic ringspot virus (HCRSV) was identified as a strong gene-silencing(More)
ABSTRACT We have developed a piezoelectric DNA-sensor based on DNA-RNA hybridization for the detection of two orchid viruses, Cymbidium mosaic virus (CymMV) and Odontoglossum ringspot virus (ORSV). Specific oligonucleotide probes modified with a mercaptohexyl group at the 5'-phosphate end were directly immobilized onto 10-MHz AT-cut quartz crystal(More)