Zusammenfassungen der Arbeitskreisbeiträge - Die DPG

POSSSIBLE ROLE OF DSRNA MYCOVIRUSES OF RHIZOCTONIA SOLANI IN
SUPPRESSION OR DECREASE OF SUGAR BEET DAMPING OFF DISEASE
Shoaei Naeeni, Saloomeh 1
1
unitC7, No6,20th Str., Velenjak.Tehran, iran
Contact: saloomeh1981@yahoo.com
A search for double- stranded RNA (dsRNA) was counducted amoung 72 isolates of the
pathogenic basidiomycete Rhizoctonia solani isolated of sugar beet in Iran. Nucleic acids
were extracted from freeze- dried mycelia and dsRNA was sepreated by celllulose CF-11
chromatography and confirmed by digestion with specific nuclease ( RNase A), dsRNA was
detected by agarose electrophoresis. 1-10 kb dsRNA was isolated from 25 isolates. To partial
curing of dsRNA we attempt to remove dsRNA by excising hyphal tips from PDA containing
the cyclohexamide (75ppm) and dsRNA removed in 14 isolates. All of these 14 isolates in
two treat of contain and free dsRNA , was examined in more details. These isolates had
pronounced morphological changes, including reduction in mycelial growth in isolates
110,144,193, reduced virulence toward sugar beet ( sugar beet damping off disease) in
isolates 156, 185, 110, 85-62-Az-4 and decrease laccase activity in isolates 151, 238, 185,
263, 110, 144, 85-61-Az-1, 85-62-Az-4. Collectively, these results suggest that this double-
stranded RNA viruses in some isolates (110,185,156, 85-62-Az-4) associated with
hypovirulence and it show the potential of using dsRNA mycoviruses as biological control
against Rhizoctonia solani.
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