Complete genome sequence of the firstchrysovirus from thephytopathogenic fungus Alternaria solani on potato in China.

Chenghui Hu,Yiran Mi,Tao Zhou,Siwei Li,Chunyan Wu,Xuehong Wu,Can Zhao,Qingnian Cai

doi:10.1007/s00705-021-05263-z

Chenghui Hu, Yiran Mi + Show 6 more

Open Access

https://doi.org/10.1007/s00705-021-05263-z

Copy DOI

Abstract

The complete genome sequence of a double-stranded RNA (dsRNA) mycovirus that was isolated from Alternaria solani strain DT-10 causing potato foliar disease was determined. The virus, designated as "Alternaria solani chrysovirus 1" (AsCV1), has four dsRNA segments (dsRNA 1-4) with a length of 3600 bp, 3128 bp, 2996 bp, and 2714 bp, respectively. The RNA-dependent RNA polymerase (RdRp, 1084 amino acids [aa]), putative capsid protein (905 aa), alphachryso-P3 (835 aa), and alphachryso-P4 (729 aa) were encoded by dsRNA1, dsRNA2, dsRNA3, and dsRNA4, respectively, which had the highest sequence identity of 41.77%-72.38% to their counterparts in Helminthosporium victoriae virus 145S (HvV145S) of the genus Alphachrysovirus, family Chrysoviridae. Moreover, the 5'-untranslated regions (UTRs) of AsCV1 dsRNA 1-4, which contained several unique inserts (3-37 bp) and deletions (5-64 bp), shared 51.65%-68.01% identity with those of HvV145S. Phylogenetic analysis based on RdRp sequences showed that AsCV1 clustered the most closely with HvV145S. Considering its distinct host specificity, the low sequence similarity of its encoded proteins to those of other viruses, the unusual features of the 5'-UTRs of its dsRNA 1-4, and the phylogenetic position of its RdRp gene, AsCV1 should be considered a member of a new species in the genus Alphachrysovirus. To the best of our knowledge, this is the first alphachrysovirus identified from phytopathogenic A. solani.

Highlights

Mycoviruses identified in fungi and oomycetes, have genomic types of double-stranded RNA, single-stranded RNA, and DNA [1]
A new alphachrysovirus was found to be associated with the A. solani strain DT-10 and designated as Alternaria solani chrysovirus 1 (AsCV1)
The full genome sequences of AsCV1 were obtained through assembling all the partial complementary DNA (cDNA) and terminal sequences with DNAMAN 7.0 (Lynnon Biosoft, USA), and deposited into the GenBank database with the accession numbers of MW656210, MW656211, MW656212, and MW656213 for dsRNA1, dsRNA2, dsRNA3, and dsRNA4, respectively

Summary

Introduction

Mycoviruses identified in fungi and oomycetes, have genomic types of double-stranded RNA (dsRNA), single-stranded RNA (ssRNA), and DNA [1]. DsRNA mycoviruses belong to seven families including Birnaviridae, Chrysoviridae, Cystoviridae, Megabirnaviridae, Partitiviridae, Picobirnaviridae, and Quadriviridae, and a new established genus Botybirnavirus [2, 3]. A. solani strain DT-10, which was recovered from diseased leaves of potato with the symptoms of early blight in Datong city, Shanxi province of China, was identified according to the methods described previously [17, 18].

Results

Conclusion