Articles
PHYTOPLASMA DISEASES OF URBAN TREE AND SHRUB SPECIES IN WESTERN CANADA
Article number
496_5
Pages
55 – 62
Language
Abstract
Focused attention has been given only recently to the decline problems in urban trees and shrubs in western Canada, although the occurrence of witches’-broom (WB) diseases of pincherry (Prunus pensylvania) and shrubby cinquefoil (Potentilla fructicosa) were first recognized in Alberta in 1975 (Hiruki, unpublished data). WB diseases of willows (Salix spp.) and chokecherry (Prunus virginiana) occurred in 1997 were found associated with phytoplasmas.
Comparative molecular studies were carried out on the phytoplasmas associated with these WB diseases, all of which cause serious damages to respective host species in the central area of Alberta.
Phytoplasma isolates of aster yellows (AY27), clover proliferation, elm yellows and Canada peach X disease were included as internal references.
Following PCR amplification with P1/P6 primers of 16S rRNA genes, nested PCR was performed with universal primers R16F2n/R2. PCR products from each phytoplasma isolate were subjected to digestion treatments with each of the restriction enzymes AluI, MseI, Sau3AI, HpaII, HhaI, and RsaI for restriction fragment length polymorphism and DNA heteroduplex mobility analyses.
The results indicated that 1997 isolates of phytoplasma associated with WB of willows is a member of the 16S rRNA group I (aster yellows and related phytoplasmas), and those of pincherry and chokecherry are members of the 16S rRNA group III (X-disease and related phytoplasmas), the isolate of shrubby cinquefiol phytoplasma is a member of the 16S rRNA group VI. This is the first report of phytoplasma identification of pincherry and shrubby cinquefoil WB.
Comparative molecular studies were carried out on the phytoplasmas associated with these WB diseases, all of which cause serious damages to respective host species in the central area of Alberta.
Phytoplasma isolates of aster yellows (AY27), clover proliferation, elm yellows and Canada peach X disease were included as internal references.
Following PCR amplification with P1/P6 primers of 16S rRNA genes, nested PCR was performed with universal primers R16F2n/R2. PCR products from each phytoplasma isolate were subjected to digestion treatments with each of the restriction enzymes AluI, MseI, Sau3AI, HpaII, HhaI, and RsaI for restriction fragment length polymorphism and DNA heteroduplex mobility analyses.
The results indicated that 1997 isolates of phytoplasma associated with WB of willows is a member of the 16S rRNA group I (aster yellows and related phytoplasmas), and those of pincherry and chokecherry are members of the 16S rRNA group III (X-disease and related phytoplasmas), the isolate of shrubby cinquefiol phytoplasma is a member of the 16S rRNA group VI. This is the first report of phytoplasma identification of pincherry and shrubby cinquefoil WB.
Publication
Authors
C. Hiruki, K.R. Wang
Keywords
Mollicutes, witches’-broom, Potentilla, Prunus, Salix, nested PCR
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