Occurrence of diverse dsRNA in a Korean population of the chestnut blight fungus, Cryphonectria parasitica.
We analysed 676 isolates from 33 Korean Cryphonectria parasitica subpopulations in Korea for dsRNA incidence and diversity. dsRNA was detected in 84 isolates. Although the dsRNA banding patterns varied in several minor bands, infected isolates could be categorized into two groups. The most common banding pattern occurred in 77 isolates and contained a 12.7-kb band indicative of Cryphonectria hypovirus 1 (CHV1), and several accompanying minor bands with sizes ranging from 0.9-5kb. Northern blot analysis revealed that all 12.7-kb fragments in the dsRNA-containing isolates hybridized to probes corresponding to open reading frames (ORFs) A and B from the reference CHV1 strain (GenBank accession no. M57938). In addition, the sequence of a 1.4-kb cDNA fragment from a representative isolate of the most common group showed 99% sequence similarity to ORF A of CHV1. However, the other group of seven isolates had distinctive bands of 3.5 and 3.3kb, but not the 12.7-kb band. Sequence comparison showed that cloned fragments of these dsRNAs were similar to those of the coat protein and RNA-dependent RNA polymerase genes of chrysovirus, which indicates the occurrence of chrysovirus in the Korean population. Fungal strain identity was assessed via RFLP analysis of the ITS regions. Among the 84 tested isolates, six had different ITS-RFLP patterns (RFLP-II) from that (RFLP-I) of C. parasitica, and are believed to be C. nitschkei, a sympatric species reported on chestnut trees in Japan. The chrysovirus and CHV1 were detected in strains showing both RFLP patterns. However, the chrysovirus was more frequent in the RFLP-II group.
Park
Seung-Moon
SM
Institute of Molecular Biology and Genetics, Research Center of Bioactive Materials, Chonbuk National University, Jeonju, Chonbuk 561-756, Republic of Korea.
Kim
Jung-Mi
JM
Chung
Hea-Jong
HJ
Lim
Jin-Young
JY
Kwon
Bo-Ra
BR
Lim
Jung-Gu
JG
Kim
Jung-Ae
JA
Kim
Myoung-Ju
MJ
Cha
Byeong-Jin
BJ
Lee
Sang-Hyun
SH
Kim
Kyung-Hee
KH
Lee
Yong-Sub
YS
Yang
Moon-Sik
MS
Kim
Dae-Hyuk
DH
D000595:Amino Acid Sequence; D001203:Ascomycota / Q000235:genetics / Q000302:isolation & purification / Q000821:virology*; D004279:DNA, Viral / Q000235:genetics / Q000302:isolation & purification*; D029962:Fagaceae / Q000382:microbiology*; D007723:Korea; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010935:Plant Diseases / Q000382:microbiology*; D012328:RNA Viruses / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification*; D012330:RNA, Double-Stranded / Q000235:genetics / Q000302:isolation & purification*; D016415:Sequence Alignment
D004279:DNA, Viral; D012330:RNA, Double-Stranded