Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.7.48 (transcriptase)
 9,479 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Crucifer crops (Brassica spp.) are important winter vegetables in Taiwan. Five viruses, including Turnip mosaic virus (TuMV), Cucumber mosaic virus (CMV), Radish mosaic virus (RaMV), Beet western yellows virus (BWYV), and Cauliflower mosaic virus (CaMV), have been detected in a range of domestic-grown crucifers during past decades (1). Field mustard plants (Brassica chinensis) showing mosaic in the leaves were collected in the ChiaYi area in December 2007. Spherical virus-like particles, approximately 30 nm in diameter, were readily observed in crude sap of symptomatic plants. Tests by ELISA failed to detect any of the aforementioned viruses. A spherical agent was isolated through mechanical inoculation onto Chenopodium quinoa, and a virus culture was established and inoculated mechanically back to the original host as well as other crucifers. Systemic mosaic appeared on inoculated B. campestris, B. chinensis, and B. juncea, whereas ringspots appeared on inoculated leaves of B. oleracea. Total RNA was extracted from symptomatic leaves and used for reverse transcription (RT)-PCR amplification using degenerate primers for comoviruses (2). Other successive fragments of RNAs 1 and 2 were amplified by specific or degenerate primers designed on the basis of sequences of published Turnip ringspot virus (TuRSV). The RNA 1 (GenBank Accession No. GU968732) and RNA 2 (No. GU968731) of the isolated virus consisted of 6,076 and 3,960 nucleotides, respectively. The number of nucleotides and the arrangement of open reading frames on both RNA 1 and RNA 2 were similar to those of comoviruses. Sequence analysis revealed that the nucleotide sequences of RNA 1 and RNA 2 shared 54.2 to 82.5% and 50.2 to 79.3% similarities, respectively, to those of comoviruses and were most similar to Turnip ringspot virus. The deduced peptides of large and small coat proteins (LCP and SCP) contain 375 amino acids (41.2 kDa) and 251 amino acids (28.5 kDa), respectively. The deduced amino acid sequences of RNA-dependent RNA polymerase (RdRp), LCP, and SCP share 92.0 to 94.5%, 93.1 to 93.3% and 87.3 to 89.6% similarity, respectively, to those of published TuRSV isolates, i.e., -B (GenBank Accession No. GQ222382), -M12 (No. FJ516746), and -Toledo (No. FJ712027) indicating that the newly isolated virus from field mustard in Taiwan is an isolate of TuRSV, hence TuRSV-TW. Comparison of LCP and SCP between current TuRSV-TW and Radish mosaic virus (RaMV; GenBank Accession No. AB295644) showed 74% similarity, which is below the species demarcation level of 75% (3), indicating its discrimination from RaMV. To our knowledge, this is the first report of the occurrence of TuRSV in Taiwan and in the subtropics. References: (1) T. H. Chen et al. Plant Pathol. Bull. 9:39, 2000. (2) V. Maliogka et al. J. Phytopathol. 152:404, 2004. (3) K. Petrzik and I. Koloniuk. Virus Genes 40:290, 2010.
 ...
PMID:First Report of Turnip ringspot virus in Field Mustard (Brassica chinensis) in Taiwan. 3073 85

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.
 ...
PMID:First Report of Broad bean wilt virus 2 Infecting Bupleurum chinense in China. 3076 58