Publications - Faculty - Recently Submitted Faculty Publications 2010
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Brlansky - Archives of Virology
The prevalence of the citrus tristeza virus trifoliate resistant breaking genotype among Puerto Rican isolates
Avijit Roy, Nandlal Choudhary, John S. Hartung and R. H. Brlansky
Abstract Citrus tristeza virus (CTV) isolates have been grouped into six genotypes: T3, T30, T36, VT, B165 and resistance breaking (RB) based on symptoms, host range and genomic sequence data. The RB genotype has recently been identified with the novel property of replicating in trifoliate orange trees, a non-host for the other five genotypes. Puerto Rican CTV isolate B301 caused mild vein clearing symptoms in Mexican lime but did not induce seedling yellows or stem pitting reactions in appropriate indicator Citrus spp., which are typical host reactions by the isolate T30. The isolate B301 was not detected by the genotype specific primers (GSPs); which identifies the five other CTV genotypes. A primer pair for RT-PCR amplification of the CTV-RB genotype was designed from the heat shock protein (p65) region based on the complete genomic sequences of trifoliate RB isolates from New Zealand and Hawaii available in the GenBank databases. The amplicon sequence from isolate B301 was similar to that of other trifoliate RB isolates. In addition, B301 was successfully inoculated into ‘Carrizo citrange’ (a trifoliate hybrid) but did not induce any symptoms. Furthermore, the complete genome sequence of B301 followed by the phylogenetic analysis revealed that the isolate is part of the RB clade with other trifoliate RB isolates from New Zealand and Hawaii. Additional CTV isolates obtained from Puerto Rico were tested with the RB-GSP and confirmed the presence of hidden trifoliate RB genotypes in mixed infection with known CTV genotypes. Although this is the first report of a CTV trifoliate RB genotype from Puerto Rico, this genotype has been present there prior to 1992.
