Infection of groundnut ringspot virus in Plumeria pudica characterized by irregular virus distribution and intermittent expression of symptoms.

Plumeria pudica, known as bridal bouquet, exhibiting characteristic symptoms of orthotospovirus infection were found in different localities in Brazil. Symptoms were restricted to leaves of the middle and lower thirds of a few branches of each plant. Electron microscopy, molecular analyses, and complete genome sequencing identified the orthotospovirus as groundnut ringspot virus (GRSV),member of the species Orthotospovirus arachianuli. The virus was poorly transmitted mechanically to P. pudica. Reverse transcription polymerase chain reaction (RT-PCR) and reverse transcription quantitative polymerase chain reaction (RT-qPCR) analyses performed using total RNA extracted from leaf blades, primary veins, petioles, and regions of petiole insertion on branches indicated the presence of GRSV, predominantly in the symptomatic leaf blades. Symptomatic branches propagate vegetatively, often resulting in plants expressing GRSV symptoms. In contrast, vegetative propagation of the asymptomatic branches of infected plants predominantly generates plants without GRSV symptoms. The resistance of P. pudica plants to GRSV infection, restricted systemic viral movement, and expression of symptoms in infected plants suggest that this orthotospovirus does not threaten this ornamental plant.

A highly specific Serratia-infecting T7-like phage inhibits biofilm formation in two different genera of the Enterobacteriaceae family.

Due to the emergence of multidrug-resistant bacteria, bacteriophages have become a viable alternative in controlling bacterial growth or biofilm formation. Biofilm is formed by extracellular polymeric substances (EPS) and is one of the factors responsible for increasing bacterial resistance. Bacteriophages have been studied as a bacterial control agent by use of phage enzymes or due to their bactericidal activities. A specific phage against Serratia marcescens was isolated in this work and was evaluated its biological and genomic aspects. The object of this study was UFV01, a bacteriophage belonging to the Podoviridae family, genus Teseptimavirus (group of lytic viruses), specific to the species S. marcescens, which may be related to several amino acid substitutions in the virus tail fibers. Despite this high specificity, the phage reduced the biofilm formation of several Escherichia coli strains without infecting them. UFV01 presents a relationship with phages of the genus Teseptimavirus, although it does not infect any of the E. coli strains evaluated, as these others do. All the characteristics make the phage an interesting alternative in biofilm control in hospital environments since small breaks in the biofilm matrix can lead to a complete collapse.

First report of groundnut ringspot virus infecting Zinnia sp. in Brazil.

Zinnia sp. is a genus belonging to Asteraceae family, originated in Mexico and adapted to a warm-hot climate (Hemmati and Mehrnoosh, 2017). Several types of zinnias with different flower color and forms are cultivated in Brazil (Min et al., 2020 and Souza Jr. et al., 2020). Characteristic symptoms of infection caused by orthotospovirus, including chlorotic spots and concentric rings on the leaves, were observed in two plants of Zinnia sp. of a florist located in the city of Piracicaba, State of São Paulo, Brazil. Orthotospovirus-like particles were observed by transmission electron microscope in leaf extracts from both plants, stained negatively with 1% uranyl acetate. By analyzing ultrathin sections of infected leaf tissues, particles of 80-100 nm in diameter were found in the lumen of the endoplasmic reticulum and nucleocapsid aggregates in the cytoplasm. Total RNA extracted separately from the leaves of both samples, using the Purelink Viral DNA / RNA kit (Thermo Fisher Scientific), was used to detect the virus by reverse transcription polymerase chain reaction (RT-PCR), using the universal primers for orthotospovirus BR60, complementary to the 3' end of the non-translated region of the S RNA (position 1 to 15 nt), and BR65, matching the nucleocapsid gene (N) (position 433 to 453 nt), generating and amplicon of 453 nt (Eiras et al., 2001). Amplicons of the expected size were obtained for the two samples. An amplicon was purified with the Wizard SV Gel and PCR Clean-Up System kit (Promega) and sequenced in both directions at Macrogen Inc (South Korea). The nucleotide sequence (GenBank MW629018) showed 99.29-99.76% identity with nucleotide sequences of the orthotospovirus groundnut ringspot virus (GRSV) isolates (GenBank MH686229 and KY400110). Leaf extracts from symptomatic plants were also analyzed by plate-trapped antigen-enzyme-linked immunosorbent assay (PTA-ELISA), using polyclonal antiserum produced against the GRSV nucleocapsid protein (Esquivel et al., 2019). The absorbance values obtained for the extracts of the two symptomatic plants of Zinnia sp. (1.3 and 1.7) were twice as high as the value obtained for the healthy plant extract (0.5). Leaf extract of symptomatic Zinnia sp. was inoculated mechanically onto leaves of healthy plants of Zinnia sp., Capsicum annuum cv. Dara, Cucumis sativus, Cucurbita pepo cv. Caserta, Chenopodium amaranticolor, Datura stramonium, Nicotiana tabacum cv. Turkish and Solanum lycopersicum cv. Compack. At 5 days post inoculation (dpi), inoculated leaves of D. stramonium reacted with local lesions, and at 9 dpi, newly developed leaves of inoculated S. lycopersicum plants showed necrotic spot and concentric ring symptoms, whereas C. annuum exhibited concentric rings at 10 dpi. Inoculated zinnia plants showed systemic chlorotic spot and concentric ring symptoms at 20 dpi, indistinguishable from those observed under natural infection. The other inoculated plant species were not symptomatic, nor the virus was detected. PTA-ELISA and RT-PCR confirmed infection with GRSV in symptomatic plants. The amplicons generated by RT-PCR of total RNA extracted from an experimentally infected plant of C. annuum and D. stramonium, and two plants of Zinnia sp. were sent for nucleotide sequencing. The obtained nucleotide sequences (MW629019, MW629020, MW629021, MW629022) shares 100% identity with the nucleotide sequence corresponding to the original GRSV isolate (MW629018) identified in Zinnia sp. This is the first report of the natural occurrence of GRSV in Zinnia sp. in Brazil. Studies on incidence and damage are needed to recommend alternatives for management.

First report of costus stripe mosaic virus infecting Tradescantia spathacea plants in Brazil.

Tradescantia spathacea (family Commelinaceae) is cultivated worldwide as an ornamental (Golczyk et al., 2013) and as medicinal plant (Tan et al., 2020). In 2019, 90 of ~180 plants of T. spathacea, grown in two beds of 4 m2 and exhibiting leaf mosaic were found in an experimental area at ESALQ/USP (Piracicaba municipality, São Paulo state, Brazil). Potyvirus-like flexuous filamentous particles were observed by transmission electron microscopy in foliar extracts of two symptomatic plants stained with 1% uranyl acetate. Total RNA was extracted using the Purelink viral RNA/DNA kit (Thermo Fisher Scientific) from leaves of two symptomatic plants and separately subjected to a reverse transcription polymerase chain reaction (RT-PCR). The potyviruses degenerate pairs of primers CIFor/CIRev (Ha et al. 2008), which amplifies a fragment corresponding to part of the cylindrical inclusion protein gene, and WCIEN/PV1 (Maciel et al. 2011), which amplifies a fragment containing part of the capsid protein gene and the 3' untranslated region, were used. The expected amplicons (~700bp) were obtained from both total RNA extracts. Two amplicons from one sample were purified using the Wizard SV Gel and PCR Clean-Up System kit (Promega) and directly sequenced in both directions at Macrogen Inc (Seoul, South Korea). The obtained nucleotide sequences (GenBank MW430005 and MW503934) shared 95.32% and 97.79% nucleotide identity, respectively, with the corresponding sequences of the Brazilian isolate of the potyvirus costus stripe mosaic virus (CoSMV, MK286375) (Alexandre et al. 2020). Extract from an infected plant of T. spathacea was mechanically inoculated in 10 healthy plants of T. spathacea and two plants each of the following species: Capsicum annuum, Chenopodium amaranticolor, Commelina benghalensis, Datura stramonium, Gomphrena globosa, Nicandra physaloides, Nicotiana tabacum cvs. Turkish and Samsun, Solanum lycopersicum, T. palida, and T. zebrina. All T. spathacea plants exhibited mosaic and severe leaf malformation. C. benghalensis plants developed mild mosaic, whereas infected T. zebrina plants were asymptomatic. The plants of other species were not infected. RT-PCR with specific CoSMV primers CoSMVHC-F and CoSMVHC-R (Alexandre et al. 2020) confirmed the infection. Nucleotide sequences of amplicons obtained from experimentally inoculated T. spathacea and T. zebrina (MW430007 and MW430008) shared 94.56% and 94.94% identity with the corresponding sequence of a Brazilian CoSMV isolate (MK286375). None of eight virus-free plants of T. spathacea inoculated with CoSMV using Aphis craccivora exhibited symptoms, nor was CoSMV detected by RT-PCR. Lack of CoSMV transmission by A. solanella, Myzus persicae, and Uroleucon sonchi was previously reported (Alexandre et al. 2020). T. spathacea plants are commonly propagated vegetatively, and by seeds. Virus-free seeds, if available, can provide an efficient and easy way to obtain healthy plants. Only three viruses were reported in plants of the genus Tradescantia: Commelina mosaic virus, tradescantia mild mosaic virus, and a not fully characterized potyvirus (Baker and Zettler, 1988; Ciuffo et al., 2006; Kitajima 2020). CoSMV was recently reported infecting Costus spiralis and C. comosus (Alexandre et al. 2020). As far as we know, this is the first report of CoSMV infecting T. spathacea plants.

Strongylodon macrobotrys: new host of soybean mosaic virus in Brazil.

Strongylodon macrobotrys, commonly known as the jade vine, emerald vine, or turquoise jade vine, is a species of Fabaceae native to the Philippines. The plants have blue-green color inflorescences, which makinge them one of the most admired ornamental plants in Brazil (Muniz et al. 2015). In addition, the plants contain compounds with anticancer properties (Ragasa et al. (2014) isolated compounds from S. macrobotrys with anticancer properties. In March 2019, an adult jade plant, grown under the trellis system in an experimental area at the campus of the University of São Paulo (USP), Piracicaba, state of São Paulo, was found showing mosaic symptoms typical of a virus infection. Preliminary examination of negatively stained leaf extracts by transmission electron microscopy detected elongated, flexuous particles similar tolike thoseat of a potyviruses. Further observations of thin sections of symptomatic leaf tissues revealed the presence of cylindrical inclusions, as well as bundles of thin, elongated, and filamentous particles, typical of potyvirus infection in epidermal, parenchymalparenchymal, and vascular regions, as well as bundles of thin, elongated and filamentous particles. Subsequent molecular and biological assays confirmed the presence of a potyvirusTo identify the species of the virus, .Presence of a potyvirus was confirmed by subsequent molecular and biological assays. Ttotal RNA was extracted from a pool of symptomatic leaves from the plant using the Purelink viral RNA/DNA kit (Thermo Fisher Scientific), and analyzed by one- step RT-PCR using potyviruses universal primers PV1/SP6 and WCIEN-sense (Mackenzie et al. 1998; Maciel et al. 2011), which amplify a 750-bp fragment. Total RNA extracted from an asymptomatic jade vine, obtained from a florist shop, was used as a negative controlincluded in the assay. PCR products at the expected size (~750-bp) were observed in the symptomatic plant but not in the asymptomatic plant. BLASTn analysis of the Nnucleotide sequence of the amplicon obtained only from total RNA of the symptomatic plant (GenBank accession no. MN970030) showed that it shares 90.82% to 97.859% identity with corresponding nucleotide sequences of the Korean isolate WS162 of soybean mosaic virus (SMV) deposited at the GenBank (, accession no. FJ640973, FJ640956, D88616). Extracts from symptomatic leaves of the jade plant wereas mechanically inoculated onto leaves of healthy plants of jade vine, Jack bean (Canavalia ensiformis), soybean cv. NA 5909 (Glycine max), cowpea (Vigna unguiculata), and passion fruit (Passiflora edulis f. flavicarpa). One plant of jade plant and four plants of each other species were inoculated , and infection was assessed based and monitored for symptom expression on symptom expression, and RT-PCR. The jade vine and Jack bean plants were infected by SMV, showingdeveloped mild mosaic symptoms approximately 60 and 15 days after inoculation, respectively , whereas the plants of other species were absent of any visible symptoms . To confirm the potyvirus identity, the jade vine samples were also tested by cConventional RT-PCR with SMV-specific primers pairs CP-F-SMV/CP-R-SMV (Jaramillo Mesa et al., 2018) and SMV-CPf/SMV-CPr (Wang and Ghabrial, 2002), thawhicht amplify fragments of 1000 990-bp and 469-bp90, respectively, nucleotides offrom the CP geneome region of SMV was performed, respectively. Amplicons of expected sizes were obtained from the total RNA of the leaves of field-infected and the mechanically inoculated plant of jade plantsvine as well as the Jack bean plants, but not from the asymptomatic jade plantvine and plants of other species the negative control. The viral nucleotide sequences obtained with the above pairs of primersBLASTn analysis of nucleotide sequences of the amplicons showed that they share 96.81% and 97.63% identity, respectively, with the same Korean SMV isolate WS162. These results demonstrate that… the field-symptomatic jade vine was infected with SMV, which is naturally transmitted by aphids speciess in a non-persistent manner and via soybean infected seeds (Hajimorad et al. 2018)( ). The virus appears to have has a restricted narrow natural host range., Aapart from soybean, and to date, it has only been reported the natural infection has been documented only in soybean, Lagenaria siceraria, Passiflora spp., Pinellia ternata, Senna occidentalis, and Vigna angularis (Almeida et al., 2002; Chakraborty et al. 2016; Hajimorad et al. 2018). To our knowledge, this is the first report of SMV in S. macrobotrys in the world. Further surveys are necessary to determine the incidence of the virus in ornamental jade plants vines and its importance as virus reservoirs for commercial soybean crops.

Genomic analysis and immune response in a murine mastitis model of vB_EcoM-UFV13, a potential biocontrol agent for use in dairy cows.

Bovine mastitis remains the main cause of economic losses for dairy farmers. Mammary pathogenic Escherichia coli (MPEC) is related to an acute mastitis and its treatment is still based on the use of antibiotics. In the era of antimicrobial resistance (AMR), bacterial viruses (bacteriophages) present as an efficient treatment or prophylactic option. However, this makes it essential that its genetic structure, stability and interaction with the host immune system be thoroughly characterized. The present study analyzed a novel, broad host-range anti-mastitis agent, the T4virus vB_EcoM-UFV13 in genomic terms, and its activity against a MPEC strain in an experimental E. coli-induced mastitis mouse model. 4,975 Single Nucleotide Polymorphisms (SNPs) were assigned between vB_EcoM-UFV13 and E. coli phage T4 genomes with high impact on coding sequences (CDS) (37.60%) for virion proteins. Phylogenetic trees and genome analysis supported a recent infection mix between vB_EcoM-UFV13 and Shigella phage Shfl2. After a viral stability evaluation (e.g pH and temperature), intramammary administration (MOI 10) resulted in a 10-fold reduction in bacterial load. Furthermore, pro-inflammatory cytokines, such as IL-6 and TNF-α, were observed after viral treatment. This work brings the whole characterization and immune response to vB_EcoM-UFV13, a biocontrol candidate for bovine mastitis.

A T4virus prevents biofilm formation by Trueperella pyogenes.

Trueperella pyogenes is an opportunistic pathogen of many animal species. It causes economic losses worldwide, through mastitis, metritis and mainly endometritis in dairy cows. The ability of this bacterium to form biofilms is implicated in chronic infections through hampering immune system recognition and antibiotic penetration. Since it is difficult to eradicate T. pyogenes infections with antibiotics, phage therapy presents itself as a non-toxic, effective and economically viable alternative. The present study evaluated the use of the bacteriophage vB_EcoM-UFV13 (UFV13) in the prevention of T. pyogenes biofilm development. Based upon two different approaches (crystal violet and sessile cell counting) we observed that only a multiplicity of infection (MOI) of 10 showed a statistically significant reduction in biofilm formation. Although the exact mechanisms of biofilm disruption and cell-adhesion inhibition have not been determined, genome sequence analysis of the Escherichia phage UFV13 revealed a repertoire of virion-associated peptidoglycan hydrolases (VAPGHs). The present study presents new findings regarding the disruption of biofilm formation of a Gram-positive bacterium. Subsequent transcriptomic and proteomic research will help us to understand the exact interaction mechanisms between UFV13 and T. pyogenes.