TY - JOUR
T1 - Molecular and biological characterization of a novel botybirnavirus identified from a Pakistani isolate of Alternaria alternata
AU - Shamsi, Wajeeha
AU - Sato, Yukiyo
AU - Jamal, Atif
AU - Shahi, Sabitree
AU - Kondo, Hideki
AU - Suzuki, Nobuhiro
AU - Bhatti, Muhammad Faraz
N1 - Funding Information:
This study was supported in part by Yomogi Inc. and Grants-in-Aid for Scientific Research on Innovative Areas from the Japanese Ministry of Education, Culture, Sports, Science and Technology (KAKENHI 25252011 and 16H06436 , 16H06429 and 16K21723 to N.S. and H. K.). WS is thankful to the Higher Education Commission (HEC) of Pakistan for fellowship under the International Research Support Initiative Program (IRSIP). The authors are grateful to Dr. Masatoki Taga for the generous gift of A. alternata strain Ally-12, and Dr. Ida Bagus Andika for fruitful discussion. The authors are also grateful to Ms. Tsugumi Shiokawa and Dr. Hiroko Tada at Division of Instrumental Analysis, Okayama University for the protein analyses.
Publisher Copyright:
© 2019 Elsevier B.V.
PY - 2019/4/2
Y1 - 2019/4/2
N2 - Mycoviruses ubiquitously infect a wide range of fungal hosts in the world. The current study reports a novel double stranded RNA (dsRNA) virus, termed Alternaria alternata botybirnavirus 1 (AaBbV1), infecting a Pakistani strain, 4a, of a phytopathogenic ascomycetous fungus Alternaria alternata. A combined approach of next generation and conventional terminal end sequencing of the viral genome revealed that the virus is a distinct member of the genus Botybirnavirus. This virus comprised of two segments (dsRNA1 and dsRNA2) of sizes 6127 bp and 5860 bp respectively. The dsRNA1-encoded protein carrying the RNA-dependent RNA polymerase domain showed 61% identity to the counterpart of Botrytis porri botybirnavirus 1 and lower levels of amino acid similarity with those of other putative botybirnaviruses and the fungal dsRNA viruses such as members of the families Totiviridae, Chrysoviridae and Megabirnaviridae. The dsRNA2-encoded protein showed resemblance with corresponding proteins of botybirnaviruses. Electron microscopy showed AaBbV1 to form spherical particles of 40 nm in diameter. Biochemical analyses showed that two structural proteins encoded by dsRNA1 and dsRNA2 underwent processing to some extent during particle purification, resulting in the appearance of multiple smaller products. Phylogenetic analyses of structural proteins suggested that their coding region might have been duplicated once and maintained without recombination. Protoplast fusion technique allowed for the introduction of AaBbV1 into a virus free Japanese strain of A. alternata and demonstrated its symptomless infection by the virus. Interesting similarities and dissimilarities between AaBbV1 and other previously reported botybirnaviruses are also discussed.
AB - Mycoviruses ubiquitously infect a wide range of fungal hosts in the world. The current study reports a novel double stranded RNA (dsRNA) virus, termed Alternaria alternata botybirnavirus 1 (AaBbV1), infecting a Pakistani strain, 4a, of a phytopathogenic ascomycetous fungus Alternaria alternata. A combined approach of next generation and conventional terminal end sequencing of the viral genome revealed that the virus is a distinct member of the genus Botybirnavirus. This virus comprised of two segments (dsRNA1 and dsRNA2) of sizes 6127 bp and 5860 bp respectively. The dsRNA1-encoded protein carrying the RNA-dependent RNA polymerase domain showed 61% identity to the counterpart of Botrytis porri botybirnavirus 1 and lower levels of amino acid similarity with those of other putative botybirnaviruses and the fungal dsRNA viruses such as members of the families Totiviridae, Chrysoviridae and Megabirnaviridae. The dsRNA2-encoded protein showed resemblance with corresponding proteins of botybirnaviruses. Electron microscopy showed AaBbV1 to form spherical particles of 40 nm in diameter. Biochemical analyses showed that two structural proteins encoded by dsRNA1 and dsRNA2 underwent processing to some extent during particle purification, resulting in the appearance of multiple smaller products. Phylogenetic analyses of structural proteins suggested that their coding region might have been duplicated once and maintained without recombination. Protoplast fusion technique allowed for the introduction of AaBbV1 into a virus free Japanese strain of A. alternata and demonstrated its symptomless infection by the virus. Interesting similarities and dissimilarities between AaBbV1 and other previously reported botybirnaviruses are also discussed.
KW - Alternaria alternata
KW - Botybirnavirus
KW - DsRNA
KW - Mycovirus
UR - http://www.scopus.com/inward/record.url?scp=85060254166&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85060254166&partnerID=8YFLogxK
U2 - 10.1016/j.virusres.2019.01.006
DO - 10.1016/j.virusres.2019.01.006
M3 - Article
C2 - 30639468
AN - SCOPUS:85060254166
VL - 263
SP - 119
EP - 128
JO - Virus Research
JF - Virus Research
SN - 0168-1702
ER -