Molecular and biological comparison of two Tomato yellow ring virus (TYRV) isolates: challenging the Tospovirus species concept.
Two strains of Tomato yellow ring virus (TYRV, genus Tospovirus), one from tomato (referred to as TYRV-t) and the other from soybean and potato (denoted TYRV-s), collected from different geographical regions in Iran, were compared. Their genomic S RNA segments differed in size by 55 nucleotides. Comparison of the S RNA intergenic regions revealed the absence of a stretch of 115 nucleotides within the S RNA segment of TYRV-s and, conversely, of 56 nts in that of TYRV-t, apparently a stable genetic difference as it was also found in another isolate of TYRV-s collected from potato. Sequence comparison of the N protein ORFs revealed an identity of 92% between the N proteins of both strains, and the observed strong cross-reaction of TYRV-s in DAS-ELISA with a polyclonal antiserum directed against the TYRV-t N protein confirmed this high identity. Host range analysis revealed several differences, e.g. TYRV-s, but not TYRV-t, being able to systemically infect Nicotiana species, and TYRV-s being localised in tomato. The observed molecular and biological differences of both viruses call into question the currently used criteria for Tospovirus species demarcation.
Hassani-Mehraban
A
A
Laboratory of Virology, Wageningen University, Wageningen, The Netherlands.
Saaijer
J
J
Peters
D
D
Goldbach
R
R
Kormelink
R
R
D001483:Base Sequence; D003001:Cloning, Molecular; D017931:DNA Primers / Q000235:genetics; D007492:Iran; D018551:Solanum lycopersicum / Q000821:virology; D008969:Molecular Sequence Data; D019590:Nucleocapsid Proteins / Q000235:genetics; D010802:Phylogeny; D010935:Plant Diseases / Q000821:virology; D012367:RNA, Viral / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D011198:Solanum tuberosum / Q000821:virology; D013025:Glycine max / Q000821:virology; D013045:Species Specificity; D017865:Tospovirus / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification*
D017931:DNA Primers; D019590:Nucleocapsid Proteins; D012367:RNA, Viral