Quantitative analysis of transcripts of the open reading frames of Sugarcane yellow leaf virus genome by one-multiplex RT-PCR: evidence for a high transcript level of suppressor gene in sink leaves.

摘要

The transcript levels of four genome parts of the Sugarcane yellow leaf virus representing the different open reading frames were determined in sink leaves, source leaves and mature internodes of two SCYLV-susceptible and one SCYLV-resistant Hawaiian sugarcane cultivar. Amplification products were resolved by capillary gel electrophoresis and detected by fluorescence spectrophotometry. Sink leaves had higher transcript levels of ORF0-1, which codes for a suppressor protein, than source leaves and internodes. The transcript levels for ORF3-4, which code for capsid protein and movement protein, were significantly lower in source leaves in two of the three cultivars than in sink leaves and internodes. The differences between the cultivars could not be related to SCYLV resistance, however. We propose the transcription of the viral open reading frames, especially of the gene for the suppressor protein, is modulated in the plant.