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ARS Home » Pacific West Area » Parlier, California » San Joaquin Valley Agricultural Sciences Center » Crop Diseases, Pests and Genetics Research » Research » Publications at this Location » Publication #348209

Research Project: Characterization and Management of Citrus Pathogens Transmitted by Phloem-Feeding Insect Vectors

Location: Crop Diseases, Pests and Genetics Research

Title: Preinfection of citrus by RB strains of Citrus tristeza virus (CTV) negatively affected expression of a modified T36 CTV vector

item SELVARAJ, VIJAYANANDRAJ - Foreign Agricultural Service (FAS, USDA)
item MAHESHWARI, YOGITA - Foreign Agricultural Service (FAS, USDA)
item HAJERI, S - Central California Tristeza Eradication Agency
item Yokomi, Raymond - Ray

Submitted to: International Organization of Citrus Virologists Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 3/27/2018
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Genetically modified T36 Citrus tristeza virus (T36-mCTV) is showing promise in Florida to mitigate huanglongbing (HLB) by expressing antimicrobial peptides and RNAi against the presumed pathogen, “Candidatus Liberibacter asiaticus” (CLas), and its vector, the Asian citrus psyllid (ACP). To this end, the T36-mCTV vector, clone 527, carrying a green fluorescent protein (GFP) gene and a truncated citrus phytoene desaturase (tPDS) gene was established in a quarantine greenhouse in California. Citrus macrophylla preinfected with California wild type (wt) CTV isolates representing the VT, T30, S1, RB and T36 genotypes were used to examine coinfection and expression of the T36-mCTV. As expected, a T36-wt prevented superinfection by T36-mCTV by cross-protection, however, T30, S1, or VT did not prevent establishment or expression of T36-mCTV. Surprisingly, Resistance-breaking (RB) strains significantly reduced titer and GFP expression of T36-mCTV. Moreover, RB strains prevented photo bleaching expression by the tPDS gene in the T36-mCTV as compared to control treatments. The data showed that RB strains induced some superinfection exclusion of the T36-mCTV, suggesting RB strains can reduce efficacy of the T36-based mCTV gene expression and potential control of HLB. Therefore, another genotype of a mild mCTV strain, not limited by the RB strain, should be developed for use against CLas and ACP.