First Report of Broad bean wilt virus 2 Infecting Bupleurum chinense in China

Abstract

Samples of the medicinal plant, Bupleurum chinense DC., were collected in October 2007 from the garden of the Institute of Medicinal Plant Development in Beijing. Partial fragments of the genomic RNA1 and RNA2 of Broad bean wilt virus 2 (BBWV-2) were obtained from the root cDNA library of these plants. Sequence analyses showed the 1,896-nt RNA1 fragment (GenBank No. FJ485684) encoding a portion of the RNA-dependent RNA polymerase (RdRp) and the 2,017-nt RNA2 fragment (No. FJ485685) encoding 612 amino acids of the complete large (LCP) and small coat protein (SCP), respectively. The amino acid identities of LCP and SCP were 90.8 to 96.7% compared with sequences of other BBWV-2 isolates deposited in the GenBank with the highest homology to Japanese IP (No. AB018698) and the lowest to Japanese 1-2 (No. AB018701). This strongly suggests that the B. chinense plants utilized for cDNA library construction were infected by what appears to be an isolate of BBWV-2. Seeds from the same batch were sown again in the same garden in May 2008. In August 2008, approximately 30% of these plants showed mosaic, distortion, and stunting. Reverse transcription (RT)-PCR amplicons were obtained from eight symptomatic plants using a pair of conserved primers for specific detection of viruses within the Fabavirus genus (2). A symptomless plant tested negative by RT-PCR. The same single 391-bp amplicon of RNA1 (No. FJ485686) obtained from five of those eight symptomatic plants were cloned and sequenced. Sequence comparison with the corresponding sequences of other BBWV-2 isolates showed that the sequenced isolate was most closely related to B935-a Chinese faba bean isolate (No. AF149425). Crude sap of one diseased B. chinense plant was used for mechanical inoculation to Chenopodium amaranticolor Coste & Reyn. Chlorotic local lesions were observed on inoculated leaves 5 days after inoculation, and subsequently, systemic mottle and malformed symptoms appeared on the upper leaves. Twelve plants were inoculated and all plants showed symptoms of virus infection. RT-PCR tests of inoculated indicator plants showing local lesions confirmed the presence of BBWV-2. To date, Clover yellow vein virus and Lettuce mosaic virus have been isolated from the genus Bupleurum (B. griffithii hort. and B. falcatum L. sensu lato) in Japan and Israel, respectively (1,3). Furthermore, to our knowledge, no genomic sequence of BBWV-2 naturally infecting plants in the family Umbelliferae/Apiaceae has been reported. Therefore, this is the first report of BBWV-2 on B. chinense (Umbelliferae/Apiaceae), which was designated as a BC isolate of BBWV-2. In China, BBWV-2 was reported to be infecting and causing heavy losses to many plant species mostly belonging to the family Leguminosae (4). B. chinense is a commonly used bulk medicinal plant mainly cultivated in Hebei, Sichuan, Gansu, and Shanxi provinces in China for decoction pieces and extracts of its dried roots, which are also exported to Japan, Korea, and Southeast Asia. These results demonstrate the need for further assessment of BBWV-2 incidence and the losses it may cause. References: (1) J. Cohen et al. Phytoparasitica 30:88, 2002. (2) R. M. Ferrer et al. J. Virol. Methods 144:156, 2007. (3) H. Yamamoto. Jpn. J. Phytopathol. 69:420, 2003. (4) X. P. Zhou et al. Acta Phytopathol. Sin. 26:347, 1996.

Phylodynamics and Codon Usage Pattern Analysis of Broad Bean Wilt Virus 2

“…Broad bean wilt virus 2 (BBWV-2) belongs to the genus Fabavirus of the Comovirinae subfamily, Secoviridae family. BBWV-2 is an important pathogen causing extensive damage in broad bean, pepper, yam, spinach and other economically important horticultural and ornamental crops worldwide [ 1 , 2 , 3 , 4 , 5 , 6 ], and it is transmitted by aphids in a nonpersistent manner. The virions of BBWV-2 contain two proteins (large and small coat proteins) which form an icosahedral particle.…”

Molecular Characterization and Variation of the Broad bean wilt virus 2 Isolates Based on Analyses of Complete Genome Sequences

“…RNA-1 encodes five proteins including cofactor protease (Co-Pro), NTP-binding motif (NTBM), genome-linked viral protein (VPg), protease (Pro) and RNA-dependent RNA polymerase (RdRp) while RNA2 encodes three proteins including movement protein (MP), large coat protein (LCP), and small coat protein (SCP) ( Goldbach et al, 1995 ). So far, the complete nt sequences of eight BBWV2 isolates ( Ikegami et al, 1998 ; 2001 ; Kobayashi et al, 1999 ; Koh et al, 2001 ; Kuroda et al, 2000 ; Lee et al, 2000 ; Nakamura et al, 1998 ; Qi et al, 2000a ; 2000b ) and partial sequences of twenty-five BBWV2 isolates ( Ferrer et al, 2011 ; Kobayashi et al, 1999 ; 2004 ; Kondo et al, 2005 ; Sui et al, 2009 ) from various host plants have been reported.…”

Genetic Compositions of Broad bean wilt virus 2 Infecting Red Pepper in Korea

“…RNA-1 encodes five proteins containing cofactor protease (Co-pro), NTP-binding motif (NTBM), genome-linked viral protein (VPg), protease (Pro) and RNA-dependent RNA polymerase (RdRp) while RNA2 encodes three proteins containing movement protein (MP), large coat protein (LCP) and small coat protein (SCP) ( Goldbach et al, 1995 ). Up to date, the complete nucleotide sequences of eight BBWV2 isolates ( Ikegami et al, 1998 ; 2001 ; Kobayashi et al, 1999 ; Koh et al, 2001 ; Kuroda et al, 2000 ; Lee et al, 2000 ; Nakamura et al, 1998 ; Qi et al, 2000a ; 2000b ) and partial sequences of twenty-five BBWV2 isolates ( Ferrer et al, 2011 ; Kobayashi et al, 1999 ; 2004 ; Kondo et al, 2005 ; Sui et al, 2009 ) from various host plants have been reported.…”