Desiccation Alters the Stability and Distribution of Pea Seed_borne Mosaic Virus in Pea (Pisum sativum) Cotyledon Cells

As a seed transmitted pathogen, pea seed_borne mosaic virus (PSbMV) not only replicates in embryonic cells but can also withstand seed desiccation. To understand the mechanism of PSbMV tolerance to seed desiccation, the authors compared the stability of viral coat protein (CP) and the distribution of viral particles in the cotyledon cells of pea (Pisum sativum L.) embryos collected before and after the dehydration process. Before dehydration, when the embryo was fresh and immature, degradation of CP was observed and a predominantly perinuclear distribution of viral particles in the cotyledon cells was evident. After dehydration, when the embryo was dry and mature, degradation of CP did not occur and the perinuclear viral distribution disappeared. Instead, aggregates containing PSbMV CP were found in the cytoplasm. Electron microscopy showed that these aggregates were composed of PSbMV particles. The formation of PSbMV particle aggregates is apparently triggered by seed dehydration and may be favorable to the virus survival in the desiccated embryonic cells.

Reactions of Maruca Resistant Transgenic Cowpea to Cowpea Aphid-Borne Mosaic Virus

Cowpea (Vigna unguiculata L. [Walp.]) in one of the main grain legumes contributing to food security and poverty alleviation in Sub-Saharan Africa. To control the highly damaging legume pod borer Maruca vitrata F., transgenic cowpea lines expressing the insecticidal Cry1Ab Bt protein were developed. In this study, we evaluated the impact of Cry1Ab transgene expression on the susceptibility of four cowpea lines (named IT97K-T, IT98K-T, Gourgou-T and Nafi-T) and their respective non-transgenic near isogenic lines (IT97K, IT98K, Gourgou and Nafi) to Cowpea aphid-borne mosaic virus (CABMV) in greenhouse conditions. In a preliminary quality control test by enzyme-linked immunosorbent assay, the presence of Cry1Ab protein in transgenic seed lots ranged from 59% to 72%, with no significant differences among the lines (χ2 = 3.26;p = 0.35). Upon virus inoculation, all cowpea lines exhibited mosaic symptoms with similar severity between 7- and 11-day post-inoculation. No significant differences were observed in symptom severity. Significant differences were found between cowpea lines for time of symptom onset, virus accumulation in plants and days to 50% flowering. However, while comparing pairs of transgenic lines and corresponding non-transgenic lines, virus accumulation showed not significant differences whatever the pair. Time of symptom onset and days to 50% flowering did not also differ significantly between pairs of cowpea lines except Nafi/Nafi-T in which transgenic Nafi-T showed earlier symptoms (7.4 ± 0.7 vs. 8.9 ± 0.8 days post-inoculation) and shorter flowering time (37.3 ± 0.6 vs. 42 ± 1.7 days after sowing). Overall, these findings improve our understanding of the effects of Cry1Ab gene mediated genetic modification on cowpea infection by Cowpea aphid-borne mosaic virus, with potential implications for environmental safety assessment.

A Reverse-transcription Recombinase-aided Amplification Assay for the Rapid Detection of the Far-Eastern Subtype of Tick-borne Encephalitis Virus

Objective Tick-borne encephalitis virus(TBEV) is an emerging pathogen in Europe and North Asia that causes tick-borne encephalitis(TBE). A simple, rapid method for detecting TBEV RNA is needed to control this disease. Methods A reverse-transcription recombinase-aided amplification(RT-RAA) assay was developed. This assay can be completed in one closed tube at 39℃ within 30 minutes. The sensitivity and specificity of RT-RAA were validated using non-infectious synthetic RNA representing a fragment of the NS5 region of the wild-type(WT) TBEV genome and the Senzhang strain. Additionally, 10 batches of tick samples were used to evaluate the performance of the RT-RAA assay. Results The analytical limit of detection of the assay was 20 copies per reaction of the TBEV synthetic transcript and 3 plaque-forming units(pfu) per reaction of TBEV titers. With the specific assay, no signal due to other arboviruses was observed. Of the 10 batches of tick samples obtained from the Changbai Mountains of China, three were TBEV-positive, which was consistent with the results of the quantitative real-time PCR assay. Conclusion A rapid, highly sensitive, specific, and easy-to-use method was developed for the detection of the TBEV Far-Eastern subtype.

Seed Borne Fungal Organisms Associated with Germination Success of Terminalia brownii (Fresen) in Kenya

Terminalia brownii is an indigenous tree species highly valued in the Kenyan drylands for its products such as timber for wood curving, medicine, and charcoal production, among others. Due to this high value followed by overutilization, its population in the drylands is dwindling. Concern about the species’ low regeneration as shown by low germination has been raised. This research was conducted on the seed borne fungal organisms that are associating with the germination of this species. T. brownii seeds were collected from cluster patches of the species in Kendu Bay, Kimose and Ndumoni in Homabay, Baringo and Kitui counties of Kenya respectively. The seeds were harvested for fruit probing for maturity confirmation. Random sampling was used in selecting thirty trees, 50 meters apart, from which fresh fruits were uniformly collected from the crowns. The research adopted a complete block experimental design where one hundred seeds each from the three sites, were subjected to a germination test, seed borne fungal organisms’ presence, identified organisms cultured and DNA and DNA sequencing carried out for identification. Fungal organisms associated with germination success of T. brownii were Fusarium equiseti, Pestalotia sp, and Alternaria alternata. Paired t test run between germinants versus the number of sown seeds gave N = 12, p-value of 0.000, t = 16.29. On the other hand, paired t test run between fungal infected seeds with the number of germinants gave N = 12, p-0.000, t = 8.78. Fungi associated with germinants included Penicillium sp, and the data analyzed using Mann-Whitney U test run showed significant difference at a p value of 0.000. Identified organisms associating with none germination and germination success on the other hand were analyzed using descriptive analysis. Fungal organisms associating with germination success of T. brownii significantly affect germination of freshly extracted seeds from the field, hence, for maximum germination achievement, seeds should be sown while still fresh.

Prevalence of Seed-Borne Fungi Associated with Seeds of Some Selected Flowers

The prevalence of fungi associated with seeds of some selected local flowers namely cosmos, marigold, calendula, and periwinkle collected from three different locations (Arboriculture Garden, Ramna Park Garden, and Horticulture Garden) in Dhaka district and four hybrid flower seeds (African marigold, cockscomb, petunia, and Portulaca) collected from Momin Beej Ghar, Dhaka district were recorded. The results showed that the highest percent germination (91.38%) of cosmos was obtained from Horticulture garden’s seed, marigold (95.25%) obtained from Arboriculture garden’s seed, and calendula (65.88%) periwinkle (79.38%) obtained from Ramna park garden’s seeds. But in the case of hybrid seeds, African marigold showed the highest percent seed germination (98.25%). The Horticulture garden’s seed was better than the others considering the incidence of fungi in all local flower seeds tested. But periwinkle was the lowest affected seed (12.58%, 12.20%, 8.07% incidence) and marigold was the highest affected seed (40.31%, 35.33%, 31.33% incidence) collected from Arboriculture Garden, Ramna Park, and Horticulture Garden, respectively. But in hybrid flower seeds, the lowest fungal infection (3.14%) was recorded in Portulaca and petunia seeds whereas the highest (6.20%) was in African marigold seeds.

Probable beneficial effects of black seeds (Nigella sativa) in the management of langya henipavirus infection

Background:The patients with Langya henipavirus(LayV)infection are managed mainly with symptomatic treatment and supportive care.Objective:This review article focuses on the beneficial effects of black seeds(Nigella sativa)in the management of Langya henipavirus(LayV)infection.Methods:The literature was searched in online databases,including Medline/Pubmed/PMC,Google Scholar,Science Direct,Ebsco,Scopus,Web of Science,Embase,and reference lists,to identify published studies,which established beneficial effects of black seeds(N.sativa)related to signs and symptoms of LayV infection.Results:Black seeds(N.sativa)have shown potential antiviral,bronchodilatory,antihistaminic,antitussive,hepatoprotective,renoprotective,anti-inflammatory,antioxidant,and immunomodulatory properties in various clinical,animal,in-vitro,in-vivo,and in-silico studies,which would help the patients with LayV infection.Conclusion:N.sativa would be a potential herbal candidate in the management of LayV infection along with symptomatic treatment and supportive care,to prevent further deterioration,and hospitalization.The safety and efficacy of N.sativa in patients with LayV infection would further be established by future randomized controlled clinical trials.

A review of inherent beneficial effects of black seeds(Nigella sativa)in Marburg virus disease management

Background:In the management of patients with MARV infection,this review article focuses on the potential protective effects of black seeds(Nigella sativa).Methods:To find studies that evaluated various effects of black seeds(N.sativa)related to signs and symptoms of MARV infection,reference lists and databases such as Medline/Pubmed/PMC,Google Scholar,Science Direct,Ebsco,Scopus,Web of Science,and Embase were searched.Results:In numerous clinical,animal,in-vitro,in-vivo,and in-ovo studies,black seeds(N.sativa)have demonstrated potential antiviral,anti-inflammatory,antioxidant,immunomodulatory,and hepatoprotective properties that may aid in the treatment of MARV-infected patients.Conclusion:In the initial generalization phase of MARV infection,patients may use black seeds(N.sativa)as an adjunctive therapy in addition to symptomatic treatment and supportive care.Future randomized controlled clinical trials would confirm N.sativa’s efficacy and safety in MARV-infected patients.

警惕种子传带的南方番茄病毒Southern tomato virus对我国番茄产业的危害

南方番茄病毒Southern tomato virus(STV)是近年来新发现的一种侵染番茄的病毒,通常与多种病毒复合侵染,可能与番茄的褪绿、黄化、衰退、果实变小等症状相关。该病毒最早在1984年发现,并于2005年命名。我国首先于2015年在山东寿光发现。最近,我们在山东和北京市多地的番茄样品中均检测到了该病毒,并通过检测发现国内一些主要品种番茄种子的STV携带率达40%。STV基因组为一条双链RNA,隶属Amalgaviridae科Amalgavirus属,是严格种传病毒,不能通过汁液摩擦接种和嫁接传播。鉴于STV的潜在危害以及与其他病毒高度复合侵染造成的严重损失,本文介绍了STV检测方法,并提出应开展对主栽品种的种子检测和针对性防控。

Innate and adaptive immune responses that control lymph-borne viruses in the draining lymph node

The interstitial fluids in tissues are constantly drained into the lymph nodes(LNs)as lymph through afferent lymphatic vessels and from LNs into the blood through efferent lymphatics.LNs are strategically positioned and have the appropriate cellular composition to serve as sites of adaptive immune initiation against invading pathogens.However,for lymph-borne viruses,which disseminate from the entry site to other tissues through the lymphatic system,immune cells in the draining LN(dLN)also play critical roles in curbing systemic viral dissemination during primary and secondary infections.Lymph-borne viruses in tissues can be transported to dLNs as free virions in the lymph or within infected cells.Regardless of the entry mechanism,infected myeloid antigen-presenting cells,including various subtypes of dendritic cells,inflammatory monocytes,and macrophages,play a critical role in initiating the innate immune response within the dLN.This innate immune response involves cellular crosstalk between infected and bystander innate immune cells that ultimately produce type I interferons(IFN-Is)and other cytokines and recruit inflammatory monocytes and natural killer(NK)cells.IFN-I and NK cell cytotoxicity can restrict systemic viral spread during primary infections and prevent serious disease.Additionally,the memory CD8+T-cells that reside or rapidly migrate to the dLN can contribute to disease prevention during secondary viral infections.This review explores the intricate innate immune responses orchestrated within dLNs that contain primary viral infections and the role of memory CD8+T-cells following secondary infection or CD8+T-cell vaccination.

The Chikungunya virus: An emerging US pathogen

BACKGROUND:The Chikungunya(CHIK)virus was recently reported by the CDC to have spread to the United States.We report an early documented case of CHIK from the state of Pennsylvania after a patient recently returned from Haiti in June of 2014.METHODS:A 39-year-old man presented to the emergency department complaining of fever,fatigue,polyarthralgias and a diffuse rash for two days.Four days before,he returned from a mission trip to Haiti and reported that four of his accompanying friends had also become ill.A CHIK antibody titer was obtained and it was found to be positive.During his hospital stay,he responded well to supportive care,including anti-inflammatories,intravenous hydration and anti-emetics.RESULTS:His condition improved within two days and he was ultimately discharged home.CONCLUSIONS:Manifestations of CHIK can be similar to Dengue fever,which is transmitted by the same species of mosquito,and occasionally as a co-infection.Clinicians should include Chikungunya virus in their differential diagnosis of patients who present with fever,polyarthralgia and rash with a recent history of travel to endemic areas,including those within the United States.

Emergence of Toscana virus in the mediterranean area

Toscana virus(TOSV) is an arthropod-borne virus, identified in 1971, from Phlebotomus perniciosus and Phlebotomus perfiliewi in central Italy. TOSV belongs to the Phlebovirus genus within the Bunyaviridae family. As other bunyaviruses, the genome of TOSV consists of 3 segments(S for small, M for Medium, and L for Large) respectively encoding non structural and capsid proteins, envelope structural proteins, and the viral RNA-dependant RNA-polymerase. It is transmitted by sand flies. Therefore its distribution is dictated by that of the arthropod vectors, and virus circulation peaks during summertime when sandfly populations are active. Here, we reviewed the epidemiology of TOSV in the old world. First evidence of its pathogenicity for humans, specifically its propensity to cause central nervous system(CNS) infections such as meningitis and encephalitis, was reported in central Italy. After 2000, it was recognized that TOSV had a much larger geographic distribution than initially believed, and was present in most of the Western European countries located on the northern border of the Mediterranean Sea(Portugal, Spain, France, Greece, Croatia) as well as eastern countries such as Cyprus and Turkey. In the countries where TOSV is present, it is among the three most prevalent viruses in meningitis during the warm seasons, together with enteroviruses and herpesviruses. Up to now, epidemiological data concerning Northern Africa and other countries located south of the Mediterranean are scarce. TOSV must be considered an emerging pathogen. Despite the important role played by TOSV in CNS infections, it remains a neglected agent and is rarely considered by physicians in diagnostic algorithms of CNS infections and febrile illness during the warm season, probably because of the lack of information.

RAPD marker linked with sbm-1, a gene conferring resistance to pea seed-born mosaic virus

DNA markers linked with trait of disease-resistance offer a very useful tool forselection of putative disease-resistant progeny and cloning disease-resistant genes.Peaseed-born mosaic virus(PSbMV)is spread mainly through planting infected pea seeds andby non-persistent aphid transmission.Three strains of PSbMV have been identified,designated as P-1,L and P-4.Strain P-1 is most widely distributed.Four recessive

Powassan virus:A tick borne flavivirus infecting humans

Infection of humans by Powassan virus(POWV)occurs rarely but is potentially life‐threatening.First isolated in Ontario,Canada in 1958,the presence of POWV has been confirmed in three countries:Canada,the USA,and Russia.Although a limited number of human cases has been reported thus far,the infection rate has shown signs of increasing during the 21^(st) century.Interestingly,POWV and a genetically close variant,deer tick virus(DTV),are the only member of the tick‐borne flaviviruses known to be endemic in North America and maintain in respective tick‐host cycles.In this review,we briefly summarize current knowledge involving the epidemiology and etiology,pathogenesis and immunity,molecular evolution,and protein functions of POWV,aiming to increase our understanding of the virus and unlock the potential to control this lethal pathogen.These data may also provide tools to minimize the future threat of other emerging and re‐emerging viruses.

Fungi associated with wheat seed discolouration and abnormalities in <i>in-vitro</i>study

The main aim of present study is to ascertain the fungal species and their effect on germination associated with wheat seeds. Seeds of three varieties WH896, PBW-373 and HD264 of wheat (Triticum aestivum) were collected from Quarsi Agriculture Farm Aligarh. These three seed samples of wheat showing different forms of discouloration and abnormalities were screened for associated fungi. Microscopic examination of wheat seeds reveals that seeds of all the varieties of wheat possess injuries to varying extent. Detailed examination of the seeds has shown that the seeds can be classified on the basis of extent of injury in the three categories viz., seeds having minor cracks, cracks without exposed embryo and cracks with exposed embryo. Seed soaking and washing techniques were also employed. Fusarium moniliforme and Alternaria alternata were isolated from all the categories of seed tested. Floating mycelial bits and conidia of Alternaria, Fusarium, Drechslera, Curvularia lunata, Mucor were found in all the three varieties of wheat. The seeds were subjected to visual observation and examination under stereoscopic microscope. These findings are to study and detect the phytopathogenic mycoflora which causes damage and loss to our seeds and crops.

Seedling Production from Seeds of a Wild Ecotype of Vetiver Grass (<i>Vetiveria zizanioides</i>L.) in Southern China

Vetiver grass (Vetiveria zizanioides L.) is widely used for soil and water conservation, and land management. In practice, all vetiver seedlings are propagated via ramets or tillers, which cannot meet the market demand and would also destroy the original habitat. Most vetiver genotypes flower but do not produce seeds. A wild ecotype of vetiver grass originated in southern China is fertile, but the rate of seed germination is very low. This study aimed to develop a novel method to improve its seed germination and seedling establishment. In the field, the inflorescences of wild vetiver were wrapped using a transparent plastic bag with a pot containing wet soils. The effects of inflorescence bagging and Tween 80 application on seed germination and seedling growth were examined. The results showed that seed development was characterized by low seed setting rate (19.2%), uneven maturity time, easy shedding (more than 95% of spikelets shed off 20 days after flowering), therefore difficult harvest of viable seeds. Bagging the inflorescence with moist soils in pot ensured the mature seeds falling onto the nursery soil surface and absorbing water for germination while the immature seeds continued to grow on the inflorescence. Bigging not only improved seed development and maturity, saved the procedure of seed collection and storage, but also provided a humid micro-environment for seed germination and seedling growth. Tween 80 as a surfactant promoted seed water absorption, germination and seedling growth. This simple and novel method has integrated the procedures of seed collection, storage, germination and seedling establishment, and enables the production of a large number of healthy seedlings. The possible reasons for the degeneration and disappearance of the original population were also discussed from the perspective of the disadvantages of vetiver propagation.

Post-Harvest Fungi Associated with Cowpea (Vigna unguiculata L. Walp.) Seeds Produced in Burkina Faso

Cowpea is a very popular foodstuff among people in sub-Saharan Africa. In Burkina Faso, it is the main food legume, especially in rural areas. Its production is facing difficulties including post-harvest losses caused by fungi. Therefore, the objective of this study was to isolate and identify fungal strains associated with cowpea seeds produced in Burkina Faso. Thus, a total of 108 seed samples were collected in the three agro-ecological zones of Burkina Faso. The sanitary analysis of the seeds was carried out using the direct contact method. The isolation and purification of the isolates were performed on Potato Dextrose Agar medium while their identification was done through macroscopic and microscopic phenotypical characterization using different culture media (Potato Dextrose Agar (PDA), Malt Extract Agar (MEA) and Czapeck Dox Agar (CZA)) and different identification keys. A total of 10 fungal species were isolated, with predominance of Aspergillus flavus, Aspegillus niger, Macrophomina phaseolina, Fusarium oxysporium and Rhizopus sp. whose infection rates were 70.8% to 100% of seed samples. In addition to being present in all three zones, the infection rates of Aspergillus flavus (56.55%), Aspergillus niger (20.35%) and Rhizopus (32.80%) were higher in the Sahelian zone. In the Sudano-Sahelian zone, Macrophomina (50.66%) and Fusarium (18.88%) presented the highest infection rates, while Penicillium sp. showed the highest infection rate (2.84%) in the Sudanian zone. This finding demonstrated the necessity to improve post-harvest and conservation techniques of cowpea to limit crop losses and preserve the sanitary quality of this important foodstuff.

‘藏农薯1号’不同级别种薯的病毒种类及生物学性状比较

种薯退化是制约马铃薯(Solanum tuberosum L.)产业发展的重要因素,不同级别种薯播种后在田间发病情况通常差异较大,进而影响其生物学性状及经济效益。以西藏自治区选育品种‘藏农薯1号’为试验材料,分析各级种薯(原原种、原种、一级种、二级种)在田间病毒再侵染情况,比较各级种薯植株生长发育、块茎品质和产量等生物学特性。原原种植株中仅检测到马铃薯S病毒,其他级别种薯植株中可检测到马铃薯卷叶病毒和S病毒。同时,原原种植株田间马铃薯卷叶病毒和S病毒病发病率和病情指数均较低,二级种则相反。在生长发育过程中,现蕾期叶片的叶绿素含量和光合速率最高;随着种薯级别降低,叶绿素含量和光合速率呈下降趋势,而株高差异小。不同级别种薯块茎淀粉和干物质含量差异小,还原糖含量随着种薯级别降低而降低。产量和商品薯率统计结果显示,原原种最高、二级种最低,而原种和一级种之间未见显著差异。考虑到种薯成本和经济效益,在‘藏农薯1号’马铃薯生产中,种薯应优先选用原种和一级种。

甘肃省常见瓜菜种传病毒病及其消毒预防措施

种传病毒病对瓜菜产量及品质的影响很大,严重时会造成大幅度减产甚至绝收。本文通过实地调研并查阅大量文献,归纳总结了甘肃省瓜菜种子常见病毒病及其消毒预防措施,并为提高瓜菜种子消毒质量,促进甘肃省瓜菜种子健康生产及农业可持续高质量发展提供了可行性建议。

壳寡糖浸种对低温下江西铅山红芽芋脱毒试管芋萌发及生理代谢的影响

江西铅山红芽芋脱毒试管芋一般在1月至2月上旬晴天播种,“倒春寒”等低温胁迫会导致早播的江西铅山红芽芋脱毒试管芋生长缓慢,出苗周期变长,严重时会造成烂种死亡,出苗率降低,影响其产量。为提高播种期江西铅山红芽芋脱毒试管芋抗寒性,该研究利用植物组织培养和植物生理学的方法测定了壳寡糖浸种后低温下江西铅山红芽芋脱毒试管芋的萌发及其相关生理指标。结果表明:200~250 mg/L壳寡糖浸种可显著促进低温下江西铅山红芽芋脱毒试管芋的萌发。与低温对照相比,当浸种浓度为200 mg/L时,在内源激素方面,有利于低温下江西铅山红芽芋脱毒试管芋萌发过程中赤霉素、玉米素核苷、多胺和茉莉酸的积累,而不利于生长素和脱落酸的积累;在抗氧化方面,提高了超氧化物歧化酶、过氧化物酶、过氧化氢酶的活性,降低了丙二醛和过氧化氢的含量;在渗透调节方面,有利于可溶性糖、可溶性蛋白、脯氨酸的积累;在代谢关键酶方面,可提高脂肪酶、蛋白酶和α-淀粉酶活性以及三磷酸腺苷含量。因此,200 mg/L壳寡糖可以调控低温下江西铅山红芽芋脱毒试管芋内源植物激素和渗透调节物质含量、抗氧化酶和代谢关键酶活性,促进其在低温下的萌发。

云南怒江番茄种植新区番茄病毒检测及病毒种传特性

病毒病对番茄生产造成严重危害,近年来在番茄种植新区发生严重,疑似为种子带毒传播。本研究通过对云南省怒江州番茄种植新区的番茄病毒病样品采用RNA-seq高通量测序,RT-PCR验证的方法检测病毒种类;对番茄病果种子进行超薄切片制样透射电子显微镜观察,将病果种子播种后对种苗进行RT-PCR带毒检测。结果表明,RNA-seq高通量测序及RT-PCR检测到的病毒有番茄环纹斑点病毒(tomato zonate spot orthotospovirus, TZSV)、番茄黄斑驳相关病毒(tomato yellow mottle-associated virus, TYMaV)、辣椒脉斑驳病毒(chili veinal mottle virus, ChiVMV)、南方番茄病毒(southern tomato virus, STV)。透射电镜观察到种胚细胞及胚乳细胞中分布典型的正番茄斑萎病毒属Orthotospovirus病毒粒体。病果种子播种28 d后的种苗具有病毒病症状,通过RT-PCR检出TZSV、ChiVMV、STV,检出率分别为60%、100%、80%。上述研究结果为TZSV通过种子传播提供了有利的证据,并为源头防控番茄病毒病提供了依据。