ABSTRACT Isolates of citrus tristeza virus (CTV) differ widely in their biological properties. These properties may depend on the structure of viral RNA populations comprising the different isolates. As a first approach to study the molecular basis of the biological variability, we have compared the sequences of multiple cDNA clones of the two terminal regions of the RNA from different CTV isol...

SUMMARY Citrus tristeza virus (CTV) has within the 3'-half of the genome ten open reading frames (ORFs) that are expressed through a series of 3'-coterminal subgenomic (sg) messenger (m)RNAs that, in general, function as monocistronic mRNAs with only the 5'-most ORF translated. Yet only nine sg mRNAs have been detected, suggesting that ORF 3, which is predicted to encode a small hydrophobic pro...

Fourier transform infrared (FTIR) spectroscopy has the ability to quickly identify the presence of specific carbohydrates in plant materials. The presence of the disease huanglongbing (HLB) in the leaves of infected citrus plants has a distinctive spectrum that can be used to distinguish an infected plant from a healthy plant. However, many citrus diseases display similar visible symptoms and a...

Citrus tristeza virus (CTV) produces more than thirty 3'- or 5'-terminal subgenomic RNAs (sgRNAs) that accumulate to various extents during replication in protoplasts and plants. Among the most unusual species are two abundant populations of small 5'-terminal sgRNAs of approximately 800 nucleotides (nt) termed low-molecular-weight tristeza (LMT1 and LMT2) RNAs. Remarkably, CTV replicons with al...

Typing of CTV based on coat protein (CP) gene has been approached in diverse ways. The basis for the assay focused on in this paper was presented some years ago and has been subject to several improvements since its appearance. Although the results obtained with this assay have been presented in diverse scientiic meetings, theses and technical seminars, so far no paper has explained the rationa...

The genetic variation of Citrus tristeza virus (CTV) was analysed by comparing the predominant sequence variants in seven genomic regions (p33, p65, p61, p18, p13, p20 and p23) of 18 pathogenically distinct isolates from seven different countries. Analyses of the selective constraints acting on each codon suggest that most regions were under purifying selection. Phylogenetic analysis shows dive...