|Mavrodieva, Vessela - USDA-APHIS-NPGBL|
|Garnsey, Stephen - USDA-ARS-USHRL (RET)|
Submitted to: Phytopathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 7, 2004
Publication Date: May 12, 2005
Citation: Hilf, M.E., Mavrodieva, V.A., Garnsey, S.M. 2005. Genetic marker analysis of a global collection of isolates of citrus tristeza virus: characterization and distribution of CTV genotypes and association with symptoms. Phytopathology. 95:909-917. Technical Abstract: Genetic markers amplified by sequence specific primers designed from the partial or complete genome sequences of Citrus tristeza virus (CTV) isolates T3, T30, T36 and VT were used to assess the genetic relatedness of isolates in an international collection of 372 exotic isolates of CTV by comparing the pattern of markers amplified from viral cDNA. Using these marker patterns, 85 isolates were judged similar to the T3 isolate, 81 to T30, 11 to T36, 89 to VT, 51 were mixedly infected by two or more identifiable viral genotypes, and 55 could not be assigned unequivocally to a group defined by the marker patterns. An analysis of the sequence of markers amplified from a small group of isolates by distance and maximum parsimony procedures supported the grouping of isolates based upon the marker patters. Specific disease symptoms induced in select citrus host plants were shared across molecular groups, although symptom severity collectively was least severe among isolates grouped by markers with the T30 isolate, and collectively was most severe among isolates grouped by markers with the T3 isolate. Individual isolates within a group showed a wide spectrum of gain or loss of symptom type and symptom severity.