Necrotic Ring Research Articles

Sonography Could Predict Complete/Near-Complete Necrosis of Thyroid Tumors After Fine-Needle Biopsy: Necrotic Ring Sign.

Necrosis, a rare histologic alteration caused by the fine-needle aspiration biopsy (FNA) of thyroid tumors, could be problematic in the clinical management of such cases due to the difficulty in making a definitive histopathologic diagnosis. The aim of this study was to define US features that may help to predict FNA-induced necrosis which is more common in oncocytic tumors. This cross-sectional study consists of all patients who underwent thyroid surgery in our center between January 2011 and December 2023. All nodules, which complete/near-complete necrosis reported on final histopathology, were included into study when full video record of preoperative US exam also available for re-evaluation. US findings of necrotic tumors compared with control group consisting of similar histopathology without necrosis. A total of 11 patients have met the inclusion criteria during study period. Of these cases, seven were papillary thyroid carcinomas and four were follicular adenomas. Among the evaluated distinctive US features, necrotic ring offers the best accuracy (88%) and area under the curve (0.91) values in detecting necrosis after FNA and most valuable when combined with lack of intranodular vascularity. In the preoperative evaluation of surgical candidates, necrotic ring, refractive edge shadowing, posterior acoustic enhancement, and lack of vascular signal may predict complete/near-complete necrosis with great accuracy.

Development of parasite complexes in the ecosystem of the rose garden of the main Botanical Garden of the Russian Academy of Sciences

The article reports on studies (2011-2022) monitoring harmful organisms in the ecosystem of the rose garden of the Main Botanical Garden of the Russian Academy of Sciences. The studies yielded data on the detection of pathogens and pests, as well as the phenotypic manifestation of pathologies and lesions. A total of 21 species of pathogens and 16 species of phytophages were identified. The species composition of harmful organisms in the ecosystem of the rose garden was defined. It is shown that at the initial stage (2011- 2013) of ecosystem establishment, no external signs of viral diseases were observed, and a low level of fungal infections was noted. The development of such harmful pathogens as Peronospora sparsa Jacz., Sphaerotheca pannosa Lev., Phragmidium disciflorum James, and Ph. tuberculatum Mull. was controlled by culling plants of susceptible varieties. The predominant pathogens included Marssonina rosae (Lib.) Died., Phyllosticta rosae Desm., and Septoria rosae Desm., and the susceptibility of specific varieties to these pathogens was established. The populations of pathogens causing spot anthracnose (Sphaceloma rosarum Pass.), ascochyta leaf spot (Ascochyta rosicola Sacc.), and cercospora leaf spot (Cercospora rosicola Pass.) were slightly less common. A wide range of signs of viral infections was identified. Nine viruses belonging to five genera were detected. The frequency of their occurrence was analyzed, and the most common viruses were identified: Prunus necrotic ring spot ilarvirus, Apple mosaic ilarvirus, Tobacco ring spot nepovirus, and Arabis mosaic nepovirus. The species diversity of phytophages was noted: leaf beetles, snout beetles, leafroller moths, sawflies, blossom weevils, earwigs, moths, leafhoppers, aphids, and true bugs. It was found that damage to plants by a range of pests reached only an average level, except for individual varieties (Red Blanket and Prosperity). In general, the phytosanitary assessment of the rose gene pool of the garden according to the phytosanitary monitoring and integrated detection revealed a wide range of parasite complexes: fourteen types of pathogenic complexes, four types of entomological complexes, and five types of entomopathogenic complexes. The tactical and basic directions for control of harmful organisms in the ecosystem of the rose garden are discussed.

Prevalence of stone fruit viruses in Russian regions and genetic analysis of PNRSV isolates

As part of monitoring works carried out by specialists of the All-Russian Plant Quarantine Center, samples of stone fruit crops collected in 20 Russian Federation subjects were tested by enzyme immunoassay for the presence of the following viruses: ACLSV, ApMV, APLPV, ArMV, CLRV, CRLV, PBNSPaV, PDV, PNRSV, PPV, PRMV, RpRSV, SLRSV, TBRV, ToRSV, and TRSV. The distribution of plum pox potyvirus (PPV), prunus necrotic ring spot ilarvirus (PNRSV), and prune dwarf ilarvirus (PDV) was determined across the area of 12, 12, and 8 Russian Federation subjects in 14.9 %, 11.9 %, and 1.7 % of test samples, respectively. The presence of these viruses was confirmed by polymerase chain reaction with subsequent sequencing of the amplification products obtained. The occurrence of these viruses was analyzed depending on the type of plantation, plant species, and region of distribution. The envelope protein gene region of 18 PNRSV isolates from five Russian Federation subjects was analyzed, which showed a significant genetic variability of this virus among the Russian population.

Efficacy of pesticides against Nesidiocoris tenuis Reuter (Hemiptera: Miridae), an emerging threat in the cultivation of tomato in Northwest Europe

As non-chemical methods are not always effective to manage pests, the search for chemical solutions that efficiently combat pest species, while safeguarding the environment and beneficial organisms, is essential for advancing effective Integrated Pest Management (IPM) programs. Here, we investigated the efficacy of commercially available pesticides in managing Nesidiocoris tenuis, an emerging threat in the cultivation of tomato in Northwest Europe, while preserving the biocontrol agent Macrolophus pygmaeus. Fourteen pesticides were assessed for their residual toxicity on adults and nymphs in laboratory experiments, after which the most promising candidate was evaluated in cages and semi-commercial greenhouse conditions. Among the pesticides tested, chlorantraniliprole, hexythiazox, tebufenozide and azadirachtin had minimal impact on both insect species, with less than 37.5% corrected mortality. Pirimicarb, sulfoxaflor, acetamiprid, flupyradifurone, thiacloprid, tebufenpyrad, spinosad, indoxacarb, and a mixture of pyrethrins and piperonyl butoxide were harmful to N. tenuis, but also affected M. pygmaeus (up to 100% mortality). Emamectin benzoate was moderately effective to N. tenuis adults (87%) and nymphs (80%), but had limited effects on M. pygmaeus. Application of emamectin benzoate at the maximum recommended concentration resulted in a significantly higher mortality of N. tenuis adults (85%) compared to M. pygmaeus (53%) in cage experiments, while it significantly reduced N. tenuis nymphs and the number of necrotic rings in a greenhouse experiment. Emamectin benzoate emerges as a promising candidate for inclusion in IPM programs. However, further research is necessary to determine its compatibility with other management strategies for controlling N. tenuis and other tomato pests.

Rubisco small subunit (RbCS) is co-opted by potyvirids as the scaffold protein in assembling a complex for viral intercellular movement.

Plant viruses must move through plasmodesmata (PD) to complete their life cycles. For viruses in the Potyviridae family (potyvirids), three viral factors (P3N-PIPO, CI, and CP) and few host proteins are known to participate in this event. Nevertheless, not all the proteins engaging in the cell-to-cell movement of potyvirids have been discovered. Here, we found that HCPro2 encoded by areca palm necrotic ring spot virus (ANRSV) assists viral intercellular movement, which could be functionally complemented by its counterpart HCPro from a potyvirus. Affinity purification and mass spectrometry identified several viral factors (including CI and CP) and host proteins that are physically associated with HCPro2. We demonstrated that HCPro2 interacts with both CI and CP in planta in forming PD-localized complexes during viral infection. Further, we screened HCPro2-associating host proteins, and identified a common host protein in Nicotiana benthamiana-Rubisco small subunit (NbRbCS) that mediates the interactions of HCPro2 with CI or CP, and CI with CP. Knockdown of NbRbCS impairs these interactions, and significantly attenuates the intercellular and systemic movement of ANRSV and three other potyvirids (turnip mosaic virus, pepper veinal mottle virus, and telosma mosaic virus). This study indicates that a nucleus-encoded chloroplast-targeted protein is hijacked by potyvirids as the scaffold protein to assemble a complex to facilitate viral movement across cells.

First report of Streptocarpus flower break virus in Streptocarpus hybrids in Aotearoa New Zealand.

Streptocarpus (Cape primrose, family Gesneriaceae) is a genus of plants native to Southern Africa commonly grown indoors for their foliage and trumpet-shaped flowers. In Aoteroa New Zealand (NZ) to date, no viruses have been reported to infect plants of the Gesneriaceae (Veerakone et al. 2015). In September 2022, a plant of Streptocarpus hybrid exhibiting necrotic rings was observed in a hobbyist's greenhouse in Auckland, NZ. High-Throughput Sequencing (HTS) using MinIONTM (Oxford Nanopore Technologies), was applied as a first screen (Liefting et al. 2021). Phylogenetic analysis was performed using Geneious Prime 2021 (Biomatters Ltd, NZ). A BLASTn search with 622,847 obtained reads resulted in 3,260 and 4,340 matches to the sequences of Streptocarpus flower break tobamovirus (SFBV) and Impatiens necrotic spot orthotospovirus (INSV), respectively. A near-complete (98.5%) genome sequence of SFBV was obtained (GenBank accession No. OQ970154), which shared 99.52% nucleotide identity to a SFBV type isolate from Germany (GenBank accession No. NC_008365). A phylogenetic tree was also generated (e-Xtra). To confirm the presence of both viruses, leaf tissue was rub inoculated onto herbaceous indicator plants as described by Tang et al. (2013). Chenopodium amaranticolor and C. quinoa plants developed local lesions while Nicotiana occidentalis plants showed local necrosis followed by systemic leaf puckering by 14 days post inoculation (dpi). Nicotiana benthamiana and N. clevelandii plants showed systemic chlorosis but N. tabacum plants did not exhibit any symptoms by 28 dpi. Samples from indicators and Streptocarpus were tested by RT-PCR (SFBV) or RT-qPCR (INSV), using in-house designed primers: SFBV-forward (5'-GTCATCAGCCGGAGAGGTTC-3'), SFBV-reverse (5'-AGGGCGAGTCTCTTCCTCTG-3'), INSV-forward (5'-CAATCAGAGGGTGACTTGGAA-3'), INSV-reverse (5'-GACTTTCCGAAGACTTGATGC-3') and INSV-probe (5'-CCATTGTCCTTTATCATTCCAACAAG-3'). RT-PCR products (across MP and CP regions) of the expected size (357 bp) were amplified from the Streptocarpus sample and symptomatic indicators. All amplicons were sequenced in both directions and found to be identical to the obtained HTS sequence. The presence of INSV was confirmed in all Streptocarpus and inoculated indicators except N. tabacum by INSV-specific RT-qPCR. A further 77 Streptocarpus plants were collected from a greenhouse in Auckland that holds a collection of multiple Streptocarpus cultivars from across NZ and overseas. Twenty-five plants, either displaying flower colour-break (only one plant) or asymptomatic (24 plants), tested positive for SFBV by RT-PCR. All amplicons were sequenced and found to be identical. SFBV was first described from naturally infected Streptocarpus plants in 1995 in the Netherlands (Verhoeven et al. 1995), and then in Germany (Heinze et al. 2006) and the United States (Pappu & Druffel 2007). While INSV has been found in NZ in several plant genera (Veerakone et al., 2015), to our knowledge, this is the first report of SFBV in NZ. SFBV was thought to be associated with colour breaking of Streptocarpus flowers (Verhoeven et al. 1995) but the virus was detected in asymptomatic Streptocarpus plants in this study and in California (Pappu & Druffel 2007). Given SFBV-infected plants were purchased from several sources, and leaf cuttings for propagation are shared among hobbyists, SFBV is likely to have spread throughout NZ. How this will affect production is unclear at this stage.

First report of Tea plant necrotic ring blotch virus in Indonesian tea plantations

First report of <i>Tea plant necrotic ring blotch virus</i> in Indonesian tea plantations

Enhancing the biocontrol potential of the predator Nesidiocoris tenuis through genetic selection

The zoophytophagous Nesidiocoris tenuis has proven to be a highly effective natural enemy against tomato key pests. It can enhance tomato plants' defenses due to its phytophagous behavior. However, its plant feeding can result in severe plant damage when prey is scarce. Previous studies using an isofemale line demonstrated the dietary habits of N. tenuis are genetically regulated, specifically with regard to phytophagy and zoophagy. In this study, we assessed the life-history traits of the IVIA strain, selected for over 50 generations for its zoophagy and phytophagy, compared to a commercial strain. The IVIA strain developed 3.5% faster, had 34% more offspring, preyed on 34% more Ephestia kuehniella eggs, and caused 50% fewer necrotic rings on tomato plants than the commercial strain. The IVIA strain controlled B. tabaci and T. absoluta in greenhouse experiments at the same level as the commercial strain but produced less damage to the plant. We also studied the capacity of the IVIA strain to induce plant defenses. The IVIA strain increased plant defenses compared to the control, although to a lesser extent than the commercial strain. This finding confirms the reduced phytophagy of the IVIA strain. Interestingly, the use of microsatellite markers revealed genetic differentiation between the IVIA strain and the commercial strain. Our results highlight the potential of selective breeding for improving biocontrol traits of interest in N. tenuis and open the door to differentiating selected strains of N. tenuis using molecular techniques.

Molecular and biological investigating of tea plant necrotic ring blotch virus as a worldwide threat

Tea plant necrotic ring blotch virus (TPNRBV) has emerged as a significant threat to tea plantations, primarily in China. Since 2020, similar symptoms have been observed in tea plants in northern Iran, raising concerns about the spread of this viral infection. In this study, we conducted an extensive investigation involving approximately 70 samples collected from both symptomatic and asymptomatic tea plants. Using reverse transcription-polymerase chain reaction with specially designed primers, we successfully amplified DNA fragments from 26 samples, confirming the presence of TPNRBV. Subsequent sequencing of these fragments revealed various segments of the TPNRBV genome. Our phylogenetic analysis revealed that the Iranian TPNRBV isolates formed a distinct sub-cluster alongside Chinese isolates, distinguishing them from Japanese isolates. These finding sheds light on the genetic diversity and relationships of TPNRBV across different regions. Additionally, we explored the potential modes of TPNRBV transmission. Mechanical transmission experiments confirmed the ability of the virus to infect Nicotiana rustica and Chenopodium quinoa seedlings, highlighting the risk of mechanical spread within tea plantations. Moreover, we investigated seed transmission and found evidence of TPNRBV in various parts of tea seeds, suggesting the possibility of seed-borne transmission. Overall, this comprehensive study enhances our understanding of the biological and molecular characteristics of TPNRBV, an emerging threat to global tea production. Our findings provide valuable insights into the virus’s transmission dynamics and genetic diversity, which are essential for developing effective management strategies to mitigate its impact on tea cultivation worldwide.

Draft Genome Sequences of 11 Isolates of Ophiosphaerella spp., the Causal Agents of Several Turfgrass Diseases Including Spring Dead Spot of Bermudagrass and Necrotic Ring Spot of Kentucky Bluegrass

Ophiosphaerella herpotricha, O. korrae, and O. narmari are the causal agents of spring dead spot of warm-season grasses worldwide, and O. korrae is the causal agent of necrotic ring spot of cool-season grasses that primarily occurs in North and South America. All three species are considered important pathogens of turfgrasses, and there is limited genomic information about these ectotrophic, root-infecting fungi. Herein are reported the draft genome sequences of three isolates of O. herpotricha, five O. korrae, and three O. narmari isolates, furthering the knowledge about these three important turfgrass disease-causing species. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

The Occurrence and Genetic Variability of Tea Plant Necrotic Ring Blotch Virus in Fujian Province, China

Tea plant necrotic ring blotch virus (TPNRBV) is a kitavirus that poses a serious threat to the cultivation of tea, one of the most economically important plants in many Asian countries. However, the occurrence and genetic variability of this virus remain poorly understood. This study investigated the occurrence of TPNRBV in Fujian Province, China, one of the largest tea producers in the country, and determined the complete genome of 10 new TPNRBV isolates. The results revealed that TPNRBV is widespread in Fujian. The nucleotide diversity values for the RNA1-4 segments of TPNRBV were found to be 0.027, 0.016, 0.027, and 0.014, respectively. Among the seven proteins of TPNRBV, P22 was the least conserved, while MP was the most conserved. The 5′ termini of the genomic segments of TPNRBV commonly possessed a sequence of 5′-AATTACGA-3′ (RNA1-3) or 5′-ATTAACGA-3′ (RNA4). Furthermore, the 3′ non-coding region of TPNRBV RNA4 exhibited significant length variation due to frequent deletion/insertion mutations. Recombination and purifying selection likely played important roles in shaping the genetic structure of TPNRBV. These findings provide a snapshot of the epidemiology and genetic structure of TPNRBV, offering valuable information for the development of targeted strategies to control and manage TPNRBV in tea cultivation.

Combined use of zoophytophagous mirids for sustainable biological protection of greenhouse tomato crops

Tuta absoluta and Bemisia tabaci are two key worldwide tomato pests. In response to chemical control limits, the use of zoophytophagous mirid predators as biocontrol agents is being increasingly studied and proposed for the management of these pests. However, the use of some mirid species and in particular Nesidiocoris tenuis, which naturally occurs in European tomato crops, is controversial due to its ability to inflict significant damage on tomato plants (necrotic rings) in parallel of its high predation capacity. Combining other mirid species such as Macrolophus pygmaeus and Dicyphus errans with N. tenuis could reduce the population growth of T. absoluta and of B. tabaci, while maintaining N. tenuis populations below a critical crop damage threshold. In this study, we tested the effect of combining N. tenuis with M. pygmaeus (at two densities: 10 and 15 individuals per plant) and with or without D. errans (five individuals per plant) on the abundance of all insects (predators and pests) for 8 weeks. We also measured leaf damage by T. absoluta and plant and flower damage (necrotic rings, flower abortion rate) by N. tenuis. We found that the combined presence of D. errans, M. pygmaeus and N. tenuis rapidly and significantly reduced the densities of B. tabaci adults, and T. absoluta larvae and damage compared to when M. pygmaeus (with both densities) was only present with N. tenuis. The presence of D. errans was critical to reduce N. tenuis population growth and necrotic rings on tomato plants, while higher densities of M. pygmaeus density reduced the rate of aborted flowers by N. tenuis. The manipulation of M. pygmaeus densities added to the presence of D. errans could provide a sustainable solution to control multiple pests simultaneously while reducing the damaging phytophagous activity of N. tenuis in tomato crops.

Fitness and population build-up of a native predatory bug, &lt;i&gt;Nesidiocoris tenuis&lt;/i&gt;, on tomato pinworm, &lt;i&gt;Phthorimaea absoluta&lt;/i&gt;, in a modified crop habitat

The tomato pinworm damage, population build-up, the damage and longevity of native predatory bug, Nesidiocoris tenuis in sole crop and diversified crop of tomato (pumpkin and sunn hemp as border crop + a patch of sunn hemp as hedgerow) were studied. Infestation of tomato pinworm, Phthorimaea absoluta was found to be the highest in the sole crop (5.60 live mines/plant at 20 DAP) compared to the diversified crop of tomato (1.50 live mines per plant). No significant difference in the number of necrotic rings per plant was observed between the sole crop and the diversified crop of tomatoes. The development period of nymphs of N. tenuis was the shortest in tomatoes followed by pumpkin. The results of the present study confirmed the role of crop diversification in supporting the population build-up of predatory bug N. tenuis in effecting the biological control of pinworm in tomato crop.

First report of Alstroemeria necrotic streak virus infecting greenhouse bell pepper (Capsicum annuum) in Canada.

Alstroemeria necrotic streak virus (ANSV) is an Orthotospovirus that has been isolated from symptomatic Alstroemeria plant in 2010 (Hassani-Mehraban et al. 2010). It has been shown to infect crops of bell pepper (Capsicum annuum) and tomato (Solanum lycopersicum) (Olaya et al. 2017) which are two of the three biggest greenhouse crops in Canada in terms of production volume and value (Statistic Canada. 2020). In July of 2022, the entire production of bell pepper (all plants) from a greenhouse in Québec was presenting necrotic rings and discoloration in fruit and seemingly healthy leaves. Samples from these infected bell pepper were found to be negative for twenty two common viruses infecting bell pepper by ELISA immunoassay by the Laboratoire d'expertise et de diagnostic en phytoprotection (LEDP) (Québec, Canada). To identify the causal agent, double-stranded RNA was extracted from leaf and fruit of one plant to form two separate samples (leaf and fruit) and used for cDNA library preparations with Nextera XT DNA Sample Prep kit (Illumina, USA). The libraries were sequenced using Illumina Miseq (Fall et al. 2020). The same dsRNA were also sequenced with MinION nanopore sequencing method as described previously (Javaran et al. 2021; Javaran et al. 2023). The obtained raw FASTQ data were processed following the methodology described in Fall et al. 2020 and Javaran et al. 2023. The Miseq sequencing yielded over 2 million reads per sample with a percentage of mapped viral reads ranging from 26.92 to 47.29% of the total number of reads. The leaf samples were positive to Bell pepper endornavirus (BPEV) with the full genome covered 16713 times and Alstroemeria necrotic streak virus (ANSV) with 98% of the genome covered 4929 times. The MinION sequencing yielded 1,028,460 reads and the same viruses were detected with 1288 long reads (mean length of 745bp) assigned to ANSV genome. Both viruses were detected in the leaf and fruit samples. The complete ANSV genome comprising three segments (L, M, and S) was assembled and deposited in GenBank: (OQ261731-OQ261733). These L, M and S segments shown 99% nt identity with an isolate from the Columbia (GenBank: MF469036, MF469037, MF469038). It is interesting that read coverage at near the 2000th position of the S segment, was very low. This phenomenon may suggest a cleavage site nearby by a viral or host factor. ANSV was mainly found in leaf samples and very low numbers of reads in fruit samples. The presence of ANSV was confirmed by RT-PCR using the primers specific to the ANSV nucleocapsid gene Tospo_S_F (5'- CAG AAT CAG GCT GCA TTT AAT TTC C-3') and Tospo_S_R (5'-CAA CGC TTC CTT TAG CAT TAG G-3') (Gallo et al. 2019). The sequences of ∼600 bp amplicons were determined using Sanger sequencing and showed 100% nt identity with Miseq-derived sequences of ANSV. The virus has previously been detected in Colombia (Hassani-Mehraban et al. 2010) and then in California in 2018 (Tian et al. 2020). This is to our knowledge the first detection of ANSV in Canada. Bell pepper is one of the most important crops in Canada and the ANSV vector, the western flower thrips (Frankliniella occidentalis), known to spread the tomato spotted wilt virus (TSWV) is established in Canada (Allen et al. 1986). The detection of ANSV in Canada is line with the hypothesis of an international spread of this virus (Tian et al. 2020) as is it not known to spread through seeds.

A snapshot of the occurrence of and genetic variability of tea plant necrotic ring blotch virus

A snapshot of the occurrence of and genetic variability of tea plant necrotic ring blotch virus

First report of Tomato bushy stunt virus naturally infecting sugar beet in the United States.

Sugar beet (Beta vulgaris L.) is an important crop grown for its sucrose content used in sugar production around the world. Tomato bushy stunt virus (TBSV) is an RNA virus that belongs to the Tombusvirus genus of the family Tombusviridae (Hearne et al., 1990). The virus was first isolated from tomato, and it is known to infect a wide range of plants (Smith, 1935; Martelli et al., 1988; Hafez et al., 2010). In 1980, a natural infection of TBSV was reported in sugar beet leaves with chlorotic and necrotic ring spots and line pattern symptoms based on serological affinity to TBSV anti-sera in Czechoslovakia (Novak and Lanzova, 1980). In March 2021, sugarbeet plants showing stunted and bushy growth with yellowing and necrotic leaves were observed in a production field in the Imperial Valley of California. Harvested roots exhibited stunted and abnormal growth compared to roots from healthy plants (sFig. 1A). These symptoms prompted a screen for potential infection by TBSV. Root-tissue harvested from the symptomatic sugar beet was initially screened using a TBSV double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA; Agdia, Inc., Elkhart, IN), which reacted positive for TBSV. To obtain the full-length sequence of TBSV and potentially other viruses in the sample, total RNA isolated using the RNeasy Plant Mini Kit (Qiagen, Valencia, CA) from the root-tissue was subjected to high-throughput sequencing (HTS). Libraries were prepared using the TruSeq Stranded Total RNA Library Prep kit (Illumina, San Diego, CA) and sequenced using Illumina NovoSeq 6000 paired-end platform (Novogene, Sacramento, CA). A total of 52 million reads were obtained after removing the adapters and reads mapping to the host genome. These high-quality reads were de novo assembled into 75,891 contigs that are larger than 500 base pairs using the SPAdes assembler (Bankevitch et al., 2012; Prjibelski et al., 2020). The resulting contigs were searched for matching sequences to known viruses using the NCBI non-redundant database. A single contig of 4770 nts representing the full-length genome of TBSV was generated (Accession number OP477335), which showed 100% coverage to previously reported TBSV isolates 'statice' (AJ249740.1) and 'nipplefruit' (AY579432.1) with 92.19% and 91.25% nucleotide sequence identities, respectively, and thus confirming the presence of TBSV in sugar beet root-tissue. However, it showed 74% coverage with only 87% nucleotide identity to a previously reported Lettuce necrotic stunt virus (LNSV) from sugar beet, a tombusvirus that was re-classified as Moroccan pepper virus (MPV) due to high degree (>97%) of sequence identity (Obermeier et al., 2001; Wintermantel and Anchieta, 2012; Wintermantel and Hladky, 2013). The coat protein is conserved within species in tombusvirus, and it plays a significant role by providing serological relationships to tombusvirus taxonomy. The coat protein of TBSV-isolate of this study shared 98.45% and 96.91% identities at amino acid level with TBSV 'nipplefruit' (AY579432.1) and TBSV 'statice' (AJ249740.1) isolates, respectively. In contrast, it showed only 61.56% identity with the coat protein of MPV as shown in the phylogenetic tree indicating that the TBSV-isolate reported here is different from MPV (sFig. 2). To confirm the presence of TBSV, reverse-transcription (RT)-PCR was performed using the total RNA isolated from the root-tissue with primers (VR306: 5'-CGCTCACGAGCCCAGCATCCTTGA-3' and VR297: 5'-ACACCGCCACAGGAGCCATGATTG-3') designed based on the HTS data to amplify a portion of the TBSV genome. Sequencing of the RT-PCR product confirmed the presence of TBSV sequence with 99.1% identity to the TBSV-isolate identified in this study. Further, mechanical inoculation of total RNA isolated from the symptomatic sugar beet roots produced local lesions and systemic necrosis symptoms on the leaves of Chenopodium quinoa (sFig. 1B). Sequencing of the amplicon obtained using RT-PCR with primers VR306 and VR297 confirmed the presence of TBSV in C. quinoa. In addition to TBSV, several viral contigs representing Beet necrotic yellow vein virus were identified in the root-tissue indicating mixed infection in the field. To our knowledge, this is the first report that documents the occurrence of TBSV in sugar beet in the United States. Since TBSV is a soil-borne virus, our findings indicate the need for further studies focused on the frequency and coexistence of the TBSV with BNYVV in sugar beet production fields to understand the disease complexity resulting from potential mixed infections.

First Report of Tomato Spotted Wilt Virus in Oxypetalum coeruleum in Korea

&lt;i&gt;Oxypetalum coeruleum&lt;/i&gt;, commonly known as Tweedia, is a perennial herbaceous plant of the &lt;i&gt;Apocynaceae&lt;/i&gt; family native to southern Brazil and Uruguay. Tweedia plants are grown as one of the most popular ornamental flowers for floral arrangement in Korea. In May 2021, several tweedia plants in a single greenhouse in Gimje, Jeollabuk-do were found to show virus-like symptoms including necrotic rings, vein-clearing, chlorotic mottle, and mosaic on the leaves, and necrosis on the stems. Here, we have identified tomato spotted wilt virus (TSWV) in symptomatic tweedia leaves by applying high-throughput RNA sequencing. In the result, a single infection by TSWV was verified without mixed infections of different virus species. To confirm the presence of TSWV, a reverse transcription polymerase chain reaction was performed with a specific primer set to the N gene of TSWV. The complete genomic sequence of L, M, and S segments of TSWV ’Oxy’ isolate were determined and deposited in GenBank under accession numbers LC671525, LC671638, and LC671639, respectively. In the phylogenetic tree analysis by maximum likelihood method, ’Oxy’ isolate showed a high relationship with TSWV ’Gumi’ isolate from &lt;i&gt;Gerbera jamesonii&lt;/i&gt; in Gyeongsangbuk-do, Korea; for all three RNA segments. To our knowledge, this is the first report of TSWV infection of &lt;i&gt;O. coeruleum&lt;/i&gt; in Korea.

Efficacy of Nesidiocoris tenuis (Hemiptera: Miridae) and Bacillus thuringiensis (Berliner) for controlling Tuta absoluta (Lepidoptera: Gelechiidae) in greenhouse tomato crops under Kuwait hot desert climate

The South American tomato pinworm, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), is one of the most damaging insect pest of tomato worldwide. Tuta absoluta has developed resistance to a wide range of insecticides. Consequently, there is a need to develop alternative control strategies to manage the pest. We evaluated the efficacy of the predatory mirid, Nesidiocoris tenuis (Reuter) (Hemiptera: Miridae) alone, as well as in combination with the biopesticide Bacillus thuringiensis (Berliner) against T. absoluta in greenhouse tomato crops under Kuwait hot desert climate. T. absoluta infestation (larval mines/10 leaves/plant) and fruits damaged was significantly lower on treatments based on N. tenuis alone or in combination with B. thuringiensis compared with the control. No significant differences were found in larval infestation, fruit damage, and crop yield between treatments where N. tenuis was released combined with the application of B. thuringiensis compared with treatments where N. tenuis was released alone. Treatments with N. tenuis alone or in combination with B. thuringiensis resulted in 90% and 93% reduction in fruit damage, respectively. Necrotic rings on tomato plants caused by N. tenuis was minimal, and no flower abortion was observed. The potential for including B. thuringiensis and N. tenuis in an overall sustainable management program for T. absoluta is discussed.

PM 7/153 (1) Mechanical inoculation of test plants

PM 7/153 (1) Mechanical inoculation of test plants

Development of a multiplex RT-PCR and the occurrence characteristics of viral diseases in sweet cherry trees in the Shandong Province, China

Viral diseases have become a major threat to sweet cherry production worldwide. In this study, a broad survey on 17 target species of viruses was performed by RT-PCR detection of leaf samples with suspected symptoms of viral infection collected from 110 orchards in 13 cities of the Shandong Province, the largest sweet cherry production area in China. Eight viruses were identified, including little cherry virus 1, cherry green ring mottle virus, prunus necrotic ring spot virus, cherry virus A, cucumber mosaic virus, plum bark necrosis stem pitting-associated virus, prune dwarf virus and little cherry virus 2. To simultaneously detect different viruses infecting sweet cherry trees, a multiplex RT-PCR method for these 8 viruses was developed and performed. Based on the multiplex RT-PCR data, sweet cherry trees in most orchards were co-infected with multiple viruses, even some trees were co-infected with eight species of viruses. All of these viruses predominantly infected sweet cherry trees cultivars Hongdeng and Tieton. These viruses appear to be not evenly distributed among different regions in the Shandong Province, which Yantai and Tai'an cities represented two centers of sweet cherry virus diseases in the Shandong Province. These data will provide the basis for the detection and management of viral diseases in sweet cherry production.