Et. Steenkamp et al., Double-stranded RNA and associated virulence in South African isolates of Sphaeropsis sapinea, CAN J BOTAN, 76(8), 1998, pp. 1412-1417
Citations number
52
Categorie Soggetti
Plant Sciences
Journal title
CANADIAN JOURNAL OF BOTANY-REVUE CANADIENNE DE BOTANIQUE
Sphaeropsis sapinea (Fr.) Dyke & Sutton is an opportunistic pathogen of var
ious Pinus spp., causing severe shoot blight and dieback. Some isolates of
S, sapinea display characteristics such as reduced virulence, reduced growt
h rate, lack of pigmentation, altered colony morphology, and suppressed con
idiation. South African isolates of S. sapinea displaying a range of growth
patterns, including reduced growth rate and atypical morphology, were scre
ened for the presence of double-stranded RNA (dsRNA). They were also tested
for relative virulence in pathogenicity tests. Double stranded RNA was iso
lated by means of phenol extraction and cellulose chromatographic purificat
ion A single species of dsRNA (+/- 4.3 kilobase pairs in size) was obtained
from two slow-growing isolates and two isolates with more regular growth.
The virulence of these dsRNA-containing isolates was tested on mature Pinus
patula Schlecht, et Cham, trees. Although reduced virulence was positively
correlated with slower growth in vitro, the presence of dsRNA could not be
linked to either of these characteristics.