|Yokomi, Raymond - Ray|
|HAJERI, S - Central California Tristeza Eradication Agency|
|BEDERSKI, K - Topara Nursery|
|GIAMPETRUZZI, A - National Research Council - Italy|
|LOCONSOLE, G - National Research Council - Italy|
|SAPONARI, M - National Research Council - Italy|
Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: 5/12/2014
Publication Date: 8/9/2014
Citation: Yokomi, R.K., Hajeri, S., Bederski, K., Giampetruzzi, A., Loconsole, G., Saponari, M. 2014. Novel mild strains of Citrus tristeza virus from California and Peru. Phytopathology. 104:S3.133.
Technical Abstract: Citrus tristeza virus (CTV) has caused great economic losses to citrus worldwide. CTV isolates from California were identified which reacted to MCA13 but were mild in biological indexing tests. Molecular markers were developed to differentiate these isolates from established CTV genotypes and the isolates were designated as having a California non-standard mild (CaNS-M) genotype. Full-length genomes of representative CaNS-M isolates were obtained through deep sequencing. Alignment of these full-length sequences indicated close relatedness to reference genome NZRB-G90 (New Zealand resistance breaking [RB]). These California isolates were differentiated into two sub-groups: subgroup 1 (RB genotypes) included Fillmore and CCTEA115 that had 100% sequence identity with NZRB-90; and sub-group 2 (non-RB genotypes) included S1 and CCTEA65 that had 81% sequence identity with NZRB-G90. Characterization of CTV isolates obtained from 15-year cross-protected citrus trees from Peru showed a mixture of VT and a non-standard genotype similar to RB-CaNS-M. A similar RB-CaNS-M isolate was identified from surviving trees in California which were infected with a severe VT genotype of CTV. Therefore, CaNS-M genotypes may have potential to cross-protect against severe strains of CTV. In depth characterization of the minor variants related to these non-standard genotypes and biological tests are underway to validate this hypothesis.