Biotechnology Bulletin ›› 2020, Vol. 36 ›› Issue (10): 80-87.doi: 10.13560/j.cnki.biotech.bull.1985.2020-0479

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Genomic Characterization of a Totiviridae from the Ustilaginoidea virens Strain GZ-14-07

ZHANG Ting-ting1,3(), TENG Li1,2, CAI Xiao-yao1, LONG Hui1, LI Sheng-yu1, LIU Hong-mei1()   

  1. 1. Key Laboratory of Biology and Medical Engineering,Guizhou Medical University,Guiyang 550000
    2. School of Basic Medical Sciences,Guizhou Medical University,Guiyang 550000
    3. Key Laboratory of Environmental Pollution Monitoring and Disease Control,Ministry of Education,Guizhou Medical University,Guiyang 550000
  • Received:2020-04-23 Online:2020-10-26 Published:2020-11-02
  • Contact: LIU Hong-mei E-mail:ztt-gd@163.com;hmliu@gmc.edu.cn

Abstract:

Ustilaginoidea virens is a pathogen that causes fungi-like disease Ustilaginoidea oryzae. A mycovirus isolated from strain GZ-14-07 of U. virens was designated as Ustilaginoidea virens RNA virus 6(UvRV6)and sequenced. Mycovirus UvRV6 was extracted from the strain GZ-14-07 using CF-11 cellulose powder method and its full-length genomic sequence was obtained by random-primer amplification method. Sequence analysis,alignment and phylogenetic tree of the UvRV6 were performed using DNAMAN,BlastP and MEGA software. The complete genome sequence of the UvRV6 was determined to be 5 043 bp in length,with a GC content of 48.8%,and contained two open reading frames(ORF1 and ORF2). ORF1 had a length of 2 280 bp and encoded a 760-amino-acid protein(79.6 kD),and ORF2 was 2 385 bp long and encoded a 830-amino-acid protein(91.5 kD). ORF1- and ORF2-encoded protein had a high percentage of sequence similarity to the capsid protein and the RNA-dependent RNA polymerases(RdRps)of genus Victorivirus in the family Totiviridae,respectively. Moreover,there was an AUGA between ORF1 and ORF2,and a sequence forming H-type pseudo-knot existed in the upstream of the AUGA. These 2 sequence elements allowed ORF1 and ORF2 to be merged as a bigger ORF via a mechanism of re-initiating translation after translation ended. A phylogenetic analysis based on the alignment of RdRps of UvRV6 and other totiviruses showed the UvRV6 was clustered with the members of Victorivirus in the family Totiviridae. Therefore,UvRV6 is confirmed as a new member of Victorivirus in the family Totiviridae.

Key words: Ustilaginoidea virens, mycovirus, dsRNA, Totiviridae, Victorivirus