Identification and complete genome sequence of iris potyvirus A, which causes dwarfing and foliar chlorosis with mosaic or mottle disease symptoms on lily (Lilium lancifolium Thunb.) in China.

Lily plants (Lilium lancifolium Thunb.) exhibiting dwarfing and foliar chlorosis with mosaic or mottle disease symptoms were found in Anhui Province, China. We used high-throughput sequencing of small RNA to survey the virus in the lily cultivation region of Anhui Province. Here, we report the identification and complete genome sequence of the viral agent. It contains 9733 nucleotides, excluding the poly(A) tail, and encodes a polyprotein of 3063 amino acids. The complete polyprotein ORF shows 98.92% amino acid sequence identity with that of iris potyvirus A (GenBank MH898493). Phylogenetic analysis of coat protein sequences placed the viral agent close to members of the genus Potyvirus in the family Potyviridae, and it was therefore provisionally named iris potyvirus A isolate Anhui (IrPVA-Anhui). This is the first complete genome sequence of IrPVA-Anhui from lily plant, for which only a partial sequence from Iris domestica has been reported previously. Comparative analysis of this genome sequence with those of closely related potyviruses identified nine cleavage sites and the conserved motifs typical of potyviruses. Subsequent virus identification was performed using serological assays (ELISA and antibody-based lateral flow assays), molecular methods (RT-PCR), and a pathogenicity test. Virus particles with a length of about 700 nm, similar to viruses in the genus Potyvirus, were observed via transmission electron microscope (TEM). We back-inoculated healthy plants of multiple species to investigate the host range of the virus. It infected the original host, Iris domestica, and Nicotiana benthamiana but not Triticum aestivum, Pisum sativum, Chenopodium amaranticolor, or Datura stramonium. This is the first report of natural IrPVA-Anhui infection of lily plants in China, providing a scientific basis for IrPVA-Anhui control in future lily plantings.

Characterisation of a novel alphaendornavirus isolated from balloon flower (Platycodon grandiflorus).

The complete genome sequence of a new virus, provisionally named "balloon flower endornavirus" (BfEV), was determined following virus isolation from leaves of a balloon flower (Platycodon grandiflorum) exhibiting severe leaf shrinkage disease in Anhui Province, China. The 15,180-nucleotide genome sequence of BfEV shares 40.52% amino acid (aa) sequence identity and 98% coverage with the polyprotein of Helianthus annuus endornavirus (HaEV). The open reading frame (ORF) encodes a deduced 4,887-aa polyprotein with RNA-dependent RNA polymerase (RdRp), viral helicase (Hel) and glycosyltransferase (GT) domains. Phylogenetic analysis of the amino acid sequences of RdRp places BfEV alongside members of the genus Alphaendornavirus in the family Endornaviridae. To our knowledge, this is the first report of a complete genome sequence of a novel alphaendornavirus identified in balloon flower.