ARS | Publication request: MOLECULAR CLONING, INFECTIVITY AND SEQUENCE ANALYSIS OF A NEW CURTOVIRUS SPECIES ISOLATED FROM SPINACH

Submitted to: International Geminivirus Symposium
Publication Type: Abstract Only
Publication Acceptance Date: December 10, 2003
Publication Date: February 20, 2004
Citation: Baliji, S., Black, M.C., French, R.C., Stenger, D.C., Sunter, G. 2004. Molecular cloning, infectivity and sequence analysis of a new curtovirus species isolated from spinach. International Geminivirus Symposium. (Not published in journal.)

Technical Abstract: A curtovirus causing curly top symptoms was isolated from diseased spinach plants in Uvalde, Texas, USA in 1996. Viral DNA was purified and an infectious clone obtained. Agroinoculation, using a construct bearing full-length tandem repeats of the cloned viral genome, indicated that the virus has a wide host range including spinach, sugar beet, French beans, pumpkin, Nicotiana benthamiana, and Arabidopsis thaliana. Symptoms (severe curling of leaves and stunting) produced in spinach inoculated with cloned viral DNA were identical to those observed in field-infected spinach, thereby demonstrating Koch's postulates. Viral single-stranded and double-stranded DNA forms typical of curtovirus infection were detected in infected host plants by Southern hybridization. The complete nucleotide sequence of the infectious clone comprises 2925 nucleotides, with seven open reading frames encoding proteins similar to those of other curtoviruses. Sequence comparisons revealed that the spinach curtovirus shared less than 84% nucleotide sequence identity relative to four previously characterized curtovirus species (Beet curly top virus, Beet severe curly top virus, Beet mild curly top virus, and Horseradish curly top virus). These results indicate that the spinach curtovirus characterized here represents a new species of the genus Curtovirus, for which we propose the name Spinach curly top virus.