Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 3/15/2010
Publication Date: 6/1/2010
Citation: Roy, A., Choudhary, N., Damsteegt, V.D., Hartung, J.S., Brlansky, R. 2010. Complete 3' end genome analysis of the asymptomatic citrus tristeza virus isolate B192 and its eight single aphid transmitted subisolates. Phytopathology 100(6):S111. Interpretive Summary:
Technical Abstract: The most important viral disease of citrus is caused by Citrus tristeza virus (CTV). CTV infection often exists in field isolates as a complex of multiple genotypes. Aphid transmission is important for CTV dispersal. The complete 3' terminal half sequences of the asymptomatic CTV isolate B192 and its single aphid transmitted (AT) sub-isolates were compared. Using genotype specific primers, the CTV-B192 source was identified as mixture of T30 and VT genotypes. However the T30 genotype was absent in 1st or 2nd level AT sub-isolates. Moreover, two AT sub-isolates contained additional T3 genotype along with VT in mixed infections. These plants showed symptoms of severe vein clearing, vein corking in Mexican lime and stem pitting in sweet orange and grapefruit. The VT genotype was the minor genotype in the source isolate but was identified as the major and most transmissible genotype in the AT sub-isolates. Sequence analyses of p6, p23, p27, p33, p61 and p65 genes of CTV-B192 were homologous with asymptomatic isolate T30 while the sequence of p13, p18 and p25 genes were phylogenetically related to the New Zealand resistance breaking isolates than the T36 group isolates. The p20 sequence showed a 93% sequence identity with T36 isolates. The complete 3' terminal half sequence derived from the source and AT sub-isolates clustered with asymptomatic T30 and symptomatic VT genotypic isolates, respectively, in the phylogenetic tree.