Introduction Tomato, scientifically known as Solanum lycopersicum L., belongs to the Solanaceae family and is susceptible to various diseases, resulting in reduced yield. Among the diseases, the ...Tomato spotted wilt virus (TSWV), which belongs to the Tospovirus genus and Bunyaviridae family, causes significant damage to tomato crops and other greenhouse plants. Therefore, it is crucial to find ways to increase plant resistance and control viral infections. One effective method is through proper plant nutrition, which can enhance plant resistance by balancing fertilizer consumption and nutrient supply. Iron (Fe) is an essential element for plants and plays a significant role in increasing their tolerance to various stresses. In Order to evaluate the interaction effects of Tomato spotted wilt virus and Fe on some biochemical traits of Mobil and RioGrand tomato cultivars, a study was conducted in Birjand Faculty of Agriculture. Materials and Methods Experiment in a Random complete design with greenhouse conditions, with 3 replications and 4 treatments Done. Experimental factors include cultivar with two levels (Mobil cultivar and Rio Grand cultivar) and Fe foliar application in the presence of virus with these three (zero, 1.5 and three milliliter of Fe fertilizer per liter of water). First, two varieties of RioGrand and Mobil tomato seeds were prepared and planted in seedlings. Then, in the two-leaf stage, they were transferred to pots filled with sterile soil and kept in greenhouse conditions. After seedling establishment, the first foliar application of Fe fertilizer was done and in the five to seven leaf stage, the virus was inoculated on all leaves. Then, the second stage of fertilizer was applied 10 days after the first fertilizer and finally, after the last stage of foliar application, the samples were transferred to the laboratory. In Order to accurately investigate the effect of Fe on important plant factors, extracts were taken from the samples. Then, the amount of antioxidants, carbohydrates, Flavonoids, Chlorophyll (a, b and total chlorophyll) and phenol was measured. Finally, the final data analysis was performed using SAS statistical software. Results The results showed that the simple effect of cultivar on the amount of phenol and flavonoids was significant at the level of one percent and the highest amount of phenol was recorded in Mobil cultivar and the highest amount of flavonoids was recorded in RioGrand cultivar. The effect of treatments on chlorophyll a, total chlorophyll index and antioxidant enzymes was significant at the level of 1% probability and carbohydrate content at the level of 5% probability. The results showed that feeding Fe at a concentration of 1.5 milliliter had a favorable effect on carbohydrate content and increased its amount in infected plants compared to control plants. This Increase effect may be useful for improving tolerance in a variety of tomatoes. According to the results, an increase in foliar application concentration to 3 milliliters led to a decrease in carbohydrate levels. Mechanical inoculation with a positive sample of the virus resulted in plant contamination. However, virus infection increased carbohydrate and antioxidant enzyme levels in tomatoes. The effect of cultivar on treatment was only significant in the amount of antioxidant enzymes at a one percent probability level, with the Mobil cultivar showing the highest response to virus infection treatment. Therefore, it can be concluded that a concentration of 1.5 milliliters of Fe fertilizer could be effective in increasing carbohydrate levels, as well as utilizing enzymatic and non-enzymatic antioxidant components to prevent viral penetration to some extent and reduce symptoms, particularly in the Mobile cultivar. However, the RioGrand cultivar produced less antioxidant components. Different cultivars of the same plant species have been reported to have varying responses to different types of infections, such as viruses, fungi, and bacteria. These differences are attributed to genetic variations among cultivars, which leads to different resistance mechanisms. Conclusion The final results showed that in the early stages of greenhouse tomato growth, Fe nutrition had an effect on the biochemical properties of the plant and had a positive effect on some traits. In total, Fe fertilizer with a concentration of 1.5 milliliter increased carbohydrates in plants infected with Tomato spotted wilt virus and together with phenol and antioxidants affected the spread of the virus, especially in Mobil cultivar.
Pueraria lobata
(Willd) (
Pueraria montana var. lobata
(Willd.) Maesen & S. M. Almeida ex Sanjappa & Predeep) is an important herbal medicine used in many countries. In
P. lobata
plants showing ...symptoms of mosaic, yellow spots, and mottling, mixed infection of new viruses provisionally named
Pueraria lobata-
associated emaravirus (PloAEV, genus
Emaravirus
),
Pueraria lobata-
associated crinivirus (PloACV, genus
Crinivirus
), and isolate CQ of the previously reported kudzu mosaic virus (KuMV-CQ, genus
Begomovirus
) was confirmed through high-throughput sequencing. PloAEV has five RNA segments, encoding a putative RNA-dependent RNA polymerase, glycoprotein precursor, nucleocapsid protein, movement protein, and P5, respectively. PloACV has two RNA segments, encoding 11 putative proteins. Only PloAEV could be mechanically transmitted from mixed infected symptomatic kudzu to
Nicotiana benthamiana
plants. All three viruses were detected in 35 symptomatic samples collected from five different growing areas, whereas no viruses were detected in 21 non-symptomatic plants, suggesting a high association between these three viruses. Thus, this study provides new knowledge on the diversity and molecular characteristics of viruses in
P. lobata
plants affected by the viral disease.
Wheat streak mosaic disease is caused by wheat streak mosaic virus (WSMV) and two other viruses and persistently limits wheat yields in the Great Plains region of the United States. Seed transmission ...of viruses is an important consideration in international movement and is important epidemiologically. Seed transmission of WSMV in wheat was first reported from Australia in 2005, but there is little data from United States cultivars on the rate of seed transmission. In 2018, mechanically inoculated winter and spring wheat cultivars were evaluated in Montana. We found differences in WSMV seed transmission rates between winter and spring wheat, with average transmission rates in spring wheat (3.1%) being five times higher compared to winter wheat (0.6%). Seed transmission rates in spring wheat were twice as high as the highest previously reported transmission rate for individual genotypes, 1.5%. The results from this study provide a strong argument for increasing the current testing of seed for breeding purposes prior to international movement when WSMV has been observed and caution against using grain from WSMV-infected fields as seed source because it can heighten the risk of wheat streak mosaic outbreaks.
Application of high-throughput sequencing (HTS) technologies enabled the first identification of Physostegia chlorotic mottle virus (PhCMoV) in 2018 in Austria. Subsequently, PhCMoV was detected in ...Germany and Serbia on tomatoes showing severe fruit mottling and ripening anomalies. We report here how pre-publication data-sharing resulted in an international collaboration across eight laboratories in five countries enabling an in-depth characterization of PhCMoV. The independent studies converged toward its recent identification in eight additional European countries and confirmed its presence in samples collected 20 ago (2002). The natural plant host range was expanded from two species to nine species across seven families, and we confirmed the association of PhCMoV presence with severe fruit symptoms on economically important crops such as tomato, eggplant, and cucumber. Mechanical inoculations of selected isolates in greenhouse established the causality of the symptoms on a new indexing host range. In addition, phylogenetic analysis showed a low genomic variation across the 29 near-complete genomes sequences available. Furthermore, a strong selection pressure within a specific ecosystem was suggested by nearly identical sequences recovered from different host plants through time. Overall, this study describes the European distribution of PhCMoV on multiple plant hosts, including economically important crops which the virus can cause severe fruit symptoms for. This work demonstrates how to efficiently improve knowledge on an emergent pathogen by sharing HTS data, and provides a solid knowledge foundation for further studies on plant rhabdoviruses.
The characterization of the elusive disease agent of the potato spindle tuber disease, potato spindle tuber viroid (PSTVd), was aided by the ability to obtain large amounts of infected tomato tissue ...in a simple bioassay where PSTVd was easily mechanically transmissible to an alternate herbaceous host in which it thrived and produced dramatic symptoms in a relatively short period (Diener, Viroids. Handbook of plant virus infections: comparative diagnosis. Elsevier/North-Holland, Amsterdam, pp 913-934, 1981; Diener, Virology 45:411-428, 1971; Raymer and O'Brien, Am Pot J, 39:401-408, 1962). Reactions in the primary, or secondary, herbaceous indicator host can range from asymptomatic to severe depending upon the viroid strain, host species, and environmental conditions and can provide evidence of a viroid infection, but do not permit identification of the viroid in question. Further characterization by molecular hybridization, RT-PCR, and sequence analysis is used to determine the etiology of the disease agent. In this chapter, methods are described for mechanical inoculation of viroids to herbaceous hosts to determine the viroid nature of diseases and the experimental host range of the viroid or to shorten the time required for obtaining relatively large amounts of viroid for subsequent purification and characterization.
Cassava brown streak disease (CBSD) caused by Cassava brown streak virus (CBSV) and Ugandan cassava brown streak virus (UCBSV) is the main constraint to cassava (Manihot esculenta Crantz) production ...in Mozambique. Using RT-PCR to amplify partial coat protein nucleotide sequences, we detected for the first time the occurrence of CBSV in two non-cassava perennial wild plant species: Zanha africana (Radlk.) Exell. and Trichodesma zeylanicum (Burm.f.) R.Br., that occur widely within and near cassava fields in Nampula, Zambezia, Niassa and Cabo Delgado provinces. In addition, we also detected CBSV and UCBSV in Manihot carthaginensis subsp. glaziovii (Müell-Arg.) Allem., a wild cassava relative. These findings were verified in biological assays through mechanical inoculation of CBSV to T. zeylanicum, albeit at low rates of infection. Phylogenetic analysis clustered the CBSV isolates from the non-cassava plant species with those from cultivated cassava, with high sequence homology among CBSV (91.0–99.6%) and with UCBSV (84–92%) isolates. These results provide definitive evidence of a wider host range for CBSV and UCBSV in Mozambique, indicating that these viruses are not restricted to cultivated cassava. Our findings are key to understanding the epidemiology of CBSD and will aid in the development of sustainable management strategies for the disease.
•Alternative host plants of Cassava brown streak viruses were determined.•There was evidence of natural infection of CBSV in non-cassava relative plants.•CBSV was successfully transmitted in T. zeylanicum by mechanical inoculation.•CBSV and UCBSV, associated with CBSD in cassava, naturally infect M. glaziovii.
Pepper is widely grown vegetable crops after tomato and watermelon in the world. One of the most important diseases on pepper production is caused by Tomato spotted wilt virus (TSWV). The best way ...for the control of this disease is to use resistant varieties. This study aimed to improve TSWV resistant lines to use as a parent in long type pepper breeding studies. Three genotypes resistant to TSWV were crossed with the susceptible Serademre 8 used to be commercial. Pedigree method was applied as the breeding method. Three populations were self-pollinated for five generations. The progenies for each of populations were tested against TSWV. Mechanical inoculations were performed in each generation and the selected resistant plants were grown for self-pollination to achieve next generation. Molecular tests were applied to the plants in stages F1 and F5. Virulent strain isolated from infected pepper plants was used as a disease material in the mechanical inoculations. CAPS marker (SCAC568) linked to the TSWV resistance gene (Tsw) was used in the molecular test for verification of mechanical test. In this study, 10 lines resistant to TSWV with good features were developed. Some of the obtained TSWV resistant lines have been transferred to private sector seed companies for use in pepper breeding programs.
Virus diseases of strawberry present several complex problems. More than 25 viruses have been described in the genus
thus far. Here, we describe a novel rhabdovirus, tentatively named strawberry ...virus 1 (StrV-1), that infects
and
plants. Genomic sequences of three distinct StrV-1 genotypes co-infecting a single
host were obtained using combined Illumina and Ion Proton high-throughput sequencing. StrV-1 was transmitted to herbaceous plants via
and
, further mechanically transmitted to
37B and sub-inoculated to
,
DCL2/4i,
37B, and
plants. Irregular chlorotic sectors on leaf blades and the multiplication of calyx leaves seem to be the diagnostic symptoms for StrV-1 on indexed
clones. StrV-1 was detected in asymptomatic grafted plants and in 49 out of 159 field strawberry samples via RT-PCR followed by Sanger sequencing. The bacilliform shape of the virions, which have a cytoplasm-limited distribution, their size, and phylogenetic relationships support the assignment of StrV-1 to a distinct species of the genus
.
,
and
were shown to transmit StrV-1 under experimental conditions.
PDF
