Induction of necrosis symptoms by potato virus X in AGO2-silenced tomato plants associates with reduced transcript accumulation of copper chaperon for superoxide dismutase gene.

RNA silencing is a prominent antiviral defense mechanism in plants. When infected with a virus, RNA silencing-deficient plants tend to show exacerbated symptoms along with increased virus accumulation. However, how symptoms are exacerbated is little understood.

One-step real-time multiplex reverse transcription-polymerase chain reaction assay with melt curve analysis for detection of potato leafroll virus, potato virus S, potato virus X, and potato virus Y.

Background: Certification of seed potato as free of viruses is essential for stable potato production. Among more than 30 virus species infecting potato, potato leafroll virus (PLRV), potato virus S (PVS), potato virus X (PVX), and potato virus Y (PVY) predominate worldwide and should be the targets of a high-throughput detection protocol for seed potato quarantine.

Results: We developed an assay based on one-step real-time multiplex reverse transcription-polymerase chain reaction (mRT-PCR) with melt curve analysis for the four viruses and one internal control, potato elongation factor 1 alpha gene (EF1α).

Complete nucleotide sequence of soybean leaf rugose mosaic virus, an atypical member of the genus Bymovirus.

The host range of previously reported bymoviruses is restricted to plants belonging to the family Poaceae. Soybean leaf rugose mosaic virus (SbLRMV) from non-Poaceae plants is related to bymoviruses based on a partial genome sequence. However, unlike bymoviruses, this virus infects plants of at least four dicotyledonous families, including Fabaceae, and causes disease in soybean.

First report of soft rot of cabbage caused by Pectobacterium wasabiae in Japan.

Cabbage (Brassica oleracea var. capitata) is one of the important vegetables in Japan. In the summer of 2019, some cabbages with soft rot were found in commercial fields in Hokkaido, the northern island in Japan.

First report of soft rot of onion caused by Pectobacterium wasabiae in Japan.

Onion (Allium cepa L.) is one of the important vegetables in Japan. In the summer of 2019, onions with soft rot were found in commercial fields in Hokkaido, the northern island in Japan.

RNA silencing-related genes contribute to tolerance of infection with potato virus X and Y in a susceptible tomato plant.

Background: In plants, the RNA silencing system functions as an antiviral defense mechanism following its induction with virus-derived double-stranded RNAs. This occurs through the action of RNA silencing components, including Dicer-like (DCL) nucleases, Argonaute (AGO) proteins, and RNA-dependent RNA polymerases (RDR). Plants encode multiple AGOs, DCLs, and RDRs.

Cylindrical Inclusion Protein of Wheat Yellow Mosaic Virus Is Involved in Differential Infection of Wheat Cultivars.

Wheat yellow mosaic virus (WYMV) belongs to the genus in the family and has a bipartite genome (RNA1 and RNA2). WYMV in Japan is classified into three pathotypes (I to III) based on its pathogenicity to wheat cultivars. Among these three, pathotypes I and II are discriminated by their pathogenicity to the wheat cultivar Fukuho; pathotype I infects Fukuho but pathotype II does not.

Species Composition of Alate Aphids (Hemiptera: Aphididae) Harboring Potato Virus Y and the Harbored Virus Strains in Hokkaido, Northern Japan.

Many studies have evaluated transmission abilities of laboratory-reared aphids for potato virus Y (PVY), but few have focused on PVY-harboring species of field-collected aphids and the strains of PVY harbored by aphids. In the present study, we collected alate aphids in yellow pan traps in potato fields with Japanese commercial cultivars in Hokkaido, northern Japan in single 24-h periods during the tuber bulking stage and examined whether individual whole aphids harbored PVY by nested RT-PCR. PVY-positive individuals were identified to species using the gene sequence for cytochrome c oxidase subunit I and, when needed, morphological data and distribution records.

Biological and genetic diversity of Wheat yellow mosaic virus (Genus Bymovirus).

The biological and genetic diversity of Wheat yellow mosaic virus (WYMV) isolates in Japan was characterized. On the basis of wheat cultivar reactions, 14 WYMV isolates from various places were classified into pathotypes I, II, or III. These were distributed in central, northern, and southern areas of Japan, respectively.

Mixed infection in tomato to ensure frequent generation of a natural reassortant between two subgroups of Cucumber mosaic virus.

Cucumber mosaic virus (CMV) is divided into subgroups I (sub-I) and II (sub-II). Isolate CMV-PF, which had been isolated from tomato by single lesion isolation (SLI), was classified in sub-II by serology, but it had the pathogenicity of sub-I CMVs. Sequence comparisons and phylogenetic analyses showed that CMV-PF was actually a reassortant CMV isolate containing RNAs 1 and 2 from sub-I and RNA 3 from sub-II (I, I, and II).

The Complete Nucleotide Sequence and Biotype Variability of Papaya leaf distortion mosaic virus.

ABSTRACT The complete nucleotide sequence of the genome of Papaya leaf distortion mosaic virus (PLDMV) was determined. The viral RNA genome of strain LDM (leaf distortion mosaic) comprised 10,153 nucleotides, excluding the poly(A) tail, and contained one long open reading frame encoding a polyprotein of 3,269 amino acids (molecular weight 373,347). The polyprotein contained nine putative proteolytic cleavage sites and some motifs conserved in other potyviral polyproteins with 44 to 50% identities, indicating that PLDMV is a distinct species in the genus Potyvirus.

A point mutation changes the serotype of a potato virus Y isolate; genomic determination of the serotype of PVY strains.

A Syrian isolate of Potato virus Y (PVY), named PVY-12, reacted to two monoclonal antibodies that are specific to PVY(O,C) and PVY(N) strains, although its coat protein (CP) belongs to the PVY(N) strain. Analysis of the CP of PVY-12 revealed that a point mutation in its N terminus switched it from PVY(N)-like to PVY(O)-like at this position. This mutation changed the second nucleotide of the codon that encodes the 29th amino acid of the CP of PVY-12 from A to G, which resulted in one amino acid substitution from Glu(29 )to Gly(29).

An efficient method for sonication assisted Agrobacterium-mediated transformation of coat protein (CP) coding genes into papaya (Carica papaya L.).

An efficient method for the production of transgenic papaya was developed via Sonication Assisted Agrobacterium-mediated Transformation (SAAT) of somatic embryos. The plasmid pGA482G was modified to contain gene PTi-Epj-TL-PLDMV with CP coding sequence of PLDMV Japan strain and chimeric gene PTi-NP-YKT with multiple CP coding sequences from PRSV Taiwan strain, PRSV Hawaii strain and PRSV Thailand strain, respectively. Disarmed Agrobacterium tumefaciens strain LBA4404 carrying the binary plasmid pGA482G with the CP genes and nptII gene was used to transform embryo calli of papaya variety Sunset to produce transgenic papaya plants.