Population diversity in grapevine yellow speckle viroid-1 and the relationship to disease expression.
Vitis vinifera cultivars Zinfandel-1A and Mission were found to harbor different grapevine yellow speckle viroid-1 (GYSVd-1) variants and characterized to define the relationship to yellow speckle (YS) and vein-banding (VB) diseases. Products from the left terminal (T1), pathogenic (P), and a portion of the central (C) domains of Zinfandel-1A and Mission displayed distinct single-stranded conformation polymorphism (SSCP) patterns, presumably reflecting nucleotide changes in the P domain. The two selections were shown to contain homogeneous populations of type 1 and type 2 GYSVd-1 variants described in Australia. Symptoms of YS were induced only in vines containing the type 2 variant by treatment at a constant temperature of 32 degreesC in continuous light. SSCP of Pagadebit selections from Italy revealed the nonsymptomatic variant was essentially identical to Zinfandel-1A, whereas symptomatic selections were unlike any other previously described. Nucleotide sequence confirmed that nonsymptomatic selections from Italy contained the GYSVd-1 type 1 variant. A total of 43 changes were spread throughout the T1, C, V, and T2 domains from symptomatic selections. This study establishes the Australian type 1 variant as the non-symptom-inducing form of GYSVd-1 and type 2 as the symptom-inducing variant. The distinct symptom-inducing variant from Italy is proposed as a new type 3 variant of GYSVd-1.
Department of Plant Pathology, University of California Riverside, Riverside, California, 92521, USA.
J A
JA
Szychowski
R
R
Credi
K
K
Reanwarakorn
J S
JS
Semancik
D001483:Base Sequence; D018076:DNA, Complementary / Q000032:analysis; D004279:DNA, Viral; D014644:Genetic Variation; D007558:Italy; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D010942:Plant Viruses / Q000145:classification / Q000235:genetics*; D017354:Point Mutation; D019685:Rosales / Q000821:virology*; D017422:Sequence Analysis, DNA; D014772:Viroids / Q000145:classification / Q000235:genetics*
D018076:DNA, Complementary; D004279:DNA, Viral