Viruses in the family
have a mono-, bi- or tripartite positive-sense RNA genome of 13-19 kb, and non-enveloped, filamentous particles 650-2200 nm long and 12 nm in diameter. They infect plants, ...mainly dicots, many of which are fruit crops. This is a summary of the ICTV Report on the family
, which is available at ictv.global/report/closteroviridae.
Hibiscus (
spp.) are popular ornamental and landscape plants in Hawaii which are susceptible to foliar diseases caused by viruses belonging to the genera
and
(family
). In this study, a virus ...infecting
plants displaying foliar symptoms consistent with infection by a kitavirus, including yellow chlorotic blotches with a green perimeter, was characterized. The genome consisted of two RNAs 8.4 and 4.4 kb in length, and was organized most similarly to cileviruses, but with important distinctions. These included the location of the p29 homolog as the 3'-terminal open reading frame (ORF) of RNA2 instead of its typical locus at the 3'-end of RNA1; the absence of a p15 homolog on RNA2 and the adjacent intergenic region which also harbors small putative ORFs of unknown function; and the presence of an ORF encoding a 10 kDa protein at the 3'-terminal end of RNA1 that was also found to be present in the hibiscus green spot virus 2 genome. Spherical particles approximately 55-65 nm in diameter were observed in infected leaf tissue, and viral RNA was detected by reverse-transcription PCR in individual mites collected from symptomatic plants tentatively identified as
. Although phylogenetic analyses placed this virus between the higrevirus and cilevirus clades, we propose the tentative taxonomic placement of this virus, designated hibiscus yellow blotch virus (HYBV), within the genus
.
Citrus leprosis complex is an emerging disease in the Americas, associated with two unrelated taxa of viruses distributed in South, Central and North America. The cytoplasmic viruses are Citrus ...leprosis virus C (CiLV-C), Citrus leprosis virus C2 (CiLV-C2) and Hibiscus green spot virus 2 (HGSV-2), whereas the nuclear viruses are Citrus leprosis virus N (CiLV-N) and Citrus necrotic spot virus (CiNSV). These viruses cause local lesion infections in all known hosts, with no natural systemic host identified to date. All leprosis viruses were believed to be transmitted by one species of mite, Brevipalpus phoenicis. However, mites collected from CiLV-C and CiLV-N infected citrus groves in Mexico were identified as B. yothersi and B. californicus sensu lato, respectively, and only B. yothersi was detected from CiLV-C2 and CiLV-N mixed infections in the Orinoco regions of Colombia. Phylogenetic analysis of the helicase, RdRp2 domains and p24 gene amino acid sequences of cytoplasmic leprosis viruses showed a close relationship with recently deposited mosquito-borne Negevirus sequences. Interestingly, we present evidence that both cytoplasmic and nuclear viruses seem to replicate in viruliferous Brevipalpus species. The possible replication in the mite vector and the close relationship with mosquito borne Negevirus are consistent with the concept that members of the genus Cilevirus and Dichorhavirus originated in mites and citrus may play the role of mite virus vector.
Based on high-throughput sequencing (HTS) data, the existence of viroid-like RNAs (Vd-LRNAs) associated with fig trees grown in the Hawaiian Islands has been predicted. One of these RNAs has been ...characterized as a circular RNA ranging in size from 357 to 360 nucleotides. Structural and biochemical features of this RNA, tentatively named fig hammerhead viroid-like RNA (FHVd-LR), markedly resemble those previously reported for several viroids and viroid-like satellite RNAs (Vd-LsatRNAs), which are non-protein-coding RNAs infecting their hosts autonomously and in combination with a helper virus, respectively. The full-length sequence of FHVd-LR variants was determined by RT-PCR, cloning, and sequencing. Despite a low global sequence identity with known viroids and Vd-LsatRNAs, FHVd-LR contains a hammerhead ribozyme (HRz) in each polarity strand. Northern blot hybridization assays identified the circular and linear forms of both polarity strands of FHVd-LR and showed that one strand, assigned the (+) polarity, accumulates at higher levels than the (-) polarity strand
The (+) polarity RNA assumes a rod-like secondary structure of minimal free energy with the conserved domains of the HRzs located in opposition to each other, a feature typical of several viroids and Vd-LRNAs. The HRzs of both FHVd-LR polarity strands were shown to be active
during transcription, self-cleaving the RNAs at the predicted sites. These data, together with the sequence variability observed in the cloned and sequenced full-length variants, indicate that FHVd-LR is a novel viroid or Vd-LsatRNA. According to HTS data, the coexistence of FHVd-LR of different sizes in the same host cannot be excluded. The relationships of FHVd-LR with previously reported viroids and Vd-LsatRNAs, and the need to perform bioassays to conclusively clarify the biological nature of this circular RNA, are discussed.
Viral diseases in plants have a significant impact on agricultural productivity. Effective detection is needed to facilitate accurate diagnosis and characterization of virus infections essential for ...crop protection and disease management. For sensitive polymerase chain reaction (PCR)-based methods, it is important to preserve the integrity of nucleic acids in plant tissue samples. This is especially critical when samples are collected from isolated areas, regions distant from a laboratory, or in developing countries that lack appropriate facilities or equipment for diagnostic analyses. RNA
later
®
provides effective, reliable sample storage by stabilizing both RNA and DNA in plant tissue samples. Our work indicated that total RNA or DNA extracted from virus-infected leaf samples preserved in RNA
later
®
was suitable for reverse transcription polymerase chain reaction (RT-PCR), PCR, Sanger sequencing, high-throughput sequencing (HTS), and enzyme-linked immunosorbent assay (ELISA)-based diagnostic analyses. We demonstrated the effectiveness of this technology using leaf tissue samples from plants with virus symptoms grown in farmers’ fields in Bangladesh. The results revealed that RNA
later
®
technology was effective for detection and characterization of viruses from samples collected from remote areas and stored for extended periods. Adoption of this technology by developing countries with limited laboratory facilities could greatly increase their capacity to detect and diagnose viral infections in crop plants using modern analytical techniques.
Air potato (
Dioscorea bulbifera
) plants being grown at the Florida Department of Agriculture and Consumer Services Division of Plant Industry Biological Control Laboratory II in Alachua County, ...Florida were observed exhibiting foliar mosaic symptoms characteristic of virus infection. A double-stranded RNA library generated from a symptomatic plant underwent high-throughput sequencing to determine if viral pathogens were present. Sequence data revealed the presence of two viral genomes, one with properties congruent with members of the genus
Potyvirus
(family
Potyviridae
), and the other with members of the genus
Ampelovirus
(family
Closteroviridae
). Sequence comparisons and phylogenetic placement indicate that both viruses represent novel species. The names “dioscorea mosaic virus” and “air potato virus 1” are proposed for the potyvirus and ampelovirus, respectively.
Hibiscus (
spp., family Malvaceae) leaves exhibiting symptoms of mosaic, ringspot, and chlorotic spots were collected in 2020 on Oahu, HI. High-throughput sequencing analysis was conducted on ...ribosomal RNA-depleted composite RNA samples extracted from symptomatic leaves. About 77 million paired-end reads and 161,970 contigs were generated after quality control, trimming, and de novo assembly. Contig annotation with BLASTX/BLASTN searches revealed a sequence (contig 1) resembling the RNA virus, hibiscus chlorotic ringspot virus (genus
), and one (contig 2) resembling the DNA virus, peanut chlorotic streak virus (genus
). Further bioinformatic analyses of the complete viral genome sequences indicated that these viruses, with proposed names of hibiscus betacarmovirus and hibiscus soymovirus, putatively represent new species in the genera
and
, respectively. RT-PCR using specific primers, designed based on the retrieved contigs, coupled with Sanger sequencing, further confirmed the presence of these viruses. An additional 54 hibiscus leaf samples from other locations on Oahu were examined to determine the incidence and distribution of these viruses.
Abstract Objectives To complement a case series review of button battery impactions managed at our single military tertiary care center with a thorough literature review of laboratory research and ...clinical cases to develop a protocol to optimize patient care. Specifically, to identify predictive factors of long-term complications which can be used by the pediatric otolaryngologist to guide patient management after button battery impactions. Methods A retrospective review of the Department of Defense’s electronic medical record systems was conducted to identify patients with button battery ingestions and then characterize their treatment course. A thorough literature review complemented the lessons learned to identify potentially predictive clinical measures for long-term complications. Results Eight patients were identified as being treated for button battery impaction in the aerodigestive tract with two sustaining long-term complications. The median age of the patients treated was 33 months old and the median estimated time of impaction in the aerodigestive tract prior to removal was 10.5 hours. Time of impaction, anatomic direction of the battery’s negative pole, and identifying specific battery parameters were identified as factors that may be employed to predict sequelae. Conclusion Based on case reviews, advancements in battery manufacturing, and laboratory research, there are distinct clinical factors that should be assessed at the time of initial therapy to guide follow-up management to minimize potential catastrophic sequelae of button battery ingestion.
The coconut rhinoceros beetle (CRB),
(L.) (Coleoptera: Scarabaeidae), has become one of the most important coconut and oil palm pests. This species was detected attacking coconut palms on O'ahu, ...Hawai'i in December 2013, and an eradication program was initiated. One of the major challenges for eradication has been the identification of new breeding sites. Information on the factors influencing oviposition is needed to aid in finding sites likely to host the immature stages of this insect. In this study, a series of choice tests were conducted to assess the oviposition preferences of both laboratory-reared and wild-caught CRB. Mated females, of both lab-reared and wild-caught beetles, were offered for oviposition a choice between sand and two mulch substrates, one with small and one with large particle sizes. Both types of CRB laid eggs preferentially in substrate of small particle size rather than large and none laid eggs in sand. Lab-reared and wild-caught CRB differed in their oviposition behavior and size. These results can be used to aid in the identification of breeding sites for management programs and eradication efforts.
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