Location: Crop Diseases, Pests and Genetics
Title: Molecular diversity of Citrus tristeza virus in California Authors
Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: May 10, 2013
Publication Date: June 30, 2013
Citation: Wang, J., Yokomi, R.K., Lee, R.F., Folimonova, S., Vidalakis, G. 2013. Molecular diversity of Citrus tristeza virus in California. Phytopathology. 103:S2.156. Technical Abstract: Citrus tristeza virus (CTV) is a serious citrus pathogen worldwide. Recent genetic studies have identified five standard CTV genotypic groups: T30, VT, T36, T3, and B165/T68. Field surveys performed in California in 2008-2010 identified primarily MCA13-negative CTV isolates with T30-like genotype. CTV isolates with T30-like genotypes in single or mixed infections with T36-nonstandard and/or VT/T3-like genotypes were also identified. These T30-like isolates caused no significant damage on citrus grafted on CTV resistant or tolerant rootstocks under California conditions. In order to elucidate the origin of the California CTV isolates, the genetic diversity of in planta CTV collections from the Citrus Clonal Protection Program at the University of California, Riverside, and the Central California Tristeza Eradication Agency were analyzed. The analysis of more than 300 CTV isolates intercepted or collected across all major California citrus-growing regions between 1960 and 2008 showed that T30 genotypes were abundant in California but a few T36-, VT-, T3- and B165/T68-like genotypes were also present at some point in time. Several CTV genotypes that could not be categorized in any known genotypic groups were also identified and classified as having a non-standard genotype. The CTV genetic diversity identified provided a valuable view of past CTV occurrence in California that will be critical for exclusion, identification, or eradication of exotic CTV isolates as well as for the development of CTV management strategies such as cross-protection.