scholarly journals Health quality and reduction of pathogenic transmission in tomato seeds using plant extracts

2019 ◽  
Vol 13 ((04) 2019) ◽  
pp. 635-641
Author(s):  
Mônica Shirley Brasil dos Santos e Silva ◽  
Antônia Alice Costa Rodrigues ◽  
Erlen Keila Candido e Silva ◽  
Anna Christina Sanazário de Oliveira ◽  
Leonardo de Jesus Machado Gois de Oliveira ◽  
...  
Keyword(s):  
Plant Extracts ◽  
Plant Pathogens ◽  
Transmission Rate ◽  
Pathogen Transmission ◽  
Tomato Seed ◽  
Tomato Seeds ◽  
Seed Analysis ◽  
Seed Health ◽  
Health Quality ◽  
Health Test

The objective of the present study was to assess the seed health quality, quantification of seed-seedling pathogen transmission and the effect of plant extracts in reducing plant pathogens in the seeds of the tomato varieties San Marzano and Ipa 6. For the seed health, the samples were disinfested, plated and assessed after seven days, according to the Brazilian Seed Analysis Rule. For the transmission rate, 12 trays were prepared with 100 seeds each and assessed at 7, 14 and 21 d.a.s. (days after seeding) using 100 seedlings. The plant (main root, stalk and leaves) tissues were plated in PDA culture medium and assessed after seven days of incubation. Aqueous extracts were prepared from cinnamon, basil, neem and eucalyptus with 0.5% concentration and the seeds were immersed in each solution for 10 minutes. Then, they plated and assessed after seven days. The health test showed that biggest incidences of Aspergillus fumigatus (26 %) and Aspergillus flavus (26 %) were occurred in the seeds of the varieties Ipa 6 and San Marzano, respectively. The fungi A. flavus, A. fumigatus, A. niger, R. stolonifer and Curvularia sp. were detected in quantification of transmission in the seeds of the two tomato varieties. The treatment with basil extract resulted in the least fungus incidence in the transmission quantification of ‘San Marzano’ tomato seeds, while on Ipa 6 seeds the eucalyptus treatment performed better. The interference of treatments was not observed in tomato seed germination. However, there was decrease in incident of pathogens in seeds treated with the plant extracts and different effects was observed based on type and species of the pathogen.

Localization and mechanical transmission of tomato brown rugose fruit virus in tomato seeds

Plant Disease ◽  
2021 ◽  
Author(s):  
Nidà Mohammed Salem ◽  
Abdullah Sulaiman ◽  
Nezar Samarah ◽  
Massimo Turina ◽  
Marta Vallino
Keyword(s):  
Seed Coat ◽  
Transmission Rate ◽  
Horizontal Transmission ◽  
Disease Outbreaks ◽  
Seed Transmission ◽  
Small Scale ◽  
Contamination Rate ◽  
Mechanical Transmission ◽  
Tomato Seed ◽  
Tomato Seeds

Tomato brown rugose fruit virus (ToBRFV), belonging to the genus Tobamovirus, is a highly virulent emerging virus, causing disease outbreaks and significant crop losses worldwide. The growing number of ToBRFV epidemic episodes prompted the investigation of the role of seeds in the dissemination of the virus as an important aspect in the overall disease management. Therefore, the objectives of this study were to determine the localization of ToBRFV within tomato seeds and to evaluate its seed transmission characteristics. Seeds extracted from naturally ToBRFV-infected tomato fruits were tested for the presence of the virus using serological, molecular, and biological assays. Three immunolocalization techniques were used to determine the localization and distribution of ToBRFV within the different tissues and parts of tomato seeds. To evaluate seed transmission of ToBRFV, two grow-out experiments were conducted to assess the rate of both vertical (seeds to progeny seedlings) and possible horizontal transmission (plant to plant) based on serological and molecular assays. Seeds extracted from ToBRFV-infected fruits had a 100% contamination rate. The localization of ToBRFV in tomato seeds is only external on the seed coat (testa). Seed transmission rate from seeds to their seedlings was very low (0.08%), while no transmission was recorded from plants to plants in a small-scale greenhouse experimental setup. In conclusion, ToBRFV is a seed-borne virus located externally on tomato seed coat and transmitted mechanically from ToBRFV-contaminated tomato seeds to seedlings which could initiate a disease foci and eventually drive further dissemination and spread of the disease in a new growing area.

scholarly journals Incidence of pathogens and field emergence of soybean seeds subjected to harvest delay

2013 ◽  
Vol 35 (4) ◽  
pp. 478-484 ◽  
Author(s):  
Fábio Oliveira Diniz ◽  
Múcio Silva Reis ◽  
Eduardo Fontes Araújo ◽  
Luiz Antônio dos Santos Dias ◽  
Tuneo Sediyama ◽  
...  
Keyword(s):  
Incidence Rate ◽  
Seedling Emergence ◽  
Growth Stages ◽  
Soybean Seeds ◽  
Fusarium Spp ◽  
Seed Health ◽  
Health Quality ◽  
Fungi Infection ◽  
Harvest Delay ◽  
Health Test

This study aimed at evaluating seed health quality, as well as seedling emergence in the field, of eight soybean cultivars (UFV-16, Splendor, Vencedora, Confiança, UFV-18, UFV-TN 105, Garantia, and Celeste) subjected to different harvest periods. To this, seeds were harvested at the growth stages R8, R8+15 days, and R8+30 days, and then submitted to health test and to the test of seedling emergence in field. Results showed that although seeds harvested at 15 and 30 days after the stage R8 had shown a significant increase of fungi infection, especially by Fusarium spp., Phomopsis spp., and Epicoccum spp., the percent seedling emergence in the field was reduced only to seeds harvested 30 days after the reproductive stage R8. Cultivars have shown differentiated behavior between each other in relation to the percent incidence rate of fungi and seedling emergence in the field; and the seeds least infected by fungi were those allowing the highest percent emergence of seedlings in the field.

scholarly journals Periodicity in Host Availability Does Not Account for Evolutionary Branching as Observed in Many Plant Pathogens: An Application to Gaeumannomyces graminis var. tritici

2010 ◽  
Vol 100 (11) ◽  
pp. 1169-1175 ◽  
Author(s):  
F. van den Berg ◽  
C. A. Gilligan ◽  
D. J. Bailey ◽  
F. van den Bosch
Keyword(s):  
Plant Pathogens ◽  
Transmission Rate ◽  
Adaptive Dynamics ◽  
Pathogen Transmission ◽  
Gaeumannomyces Graminis ◽  
Evolutionary Branching ◽  
Trade Off ◽  
Host Availability ◽  
Gaeumannomyces Graminis Var Tritici ◽  
Take All

Periodicity in host availability is common in agricultural systems. Although it is known to have profound effects on plant pathogen abundance, the evolutionary consequences of periodicity for the pathogen population have not previously been analyzed. An epidemiological model incorporating periodic absence of the host crop is combined with the theory of adaptive dynamics to determine whether or not seasonality in host presence plays a role in the occurrence of evolutionary branching, leading to coexisting yet genetically distinct pathogen phenotypes. The study is motivated and illustrated by the specific example of take-all disease of wheat, caused by the pathogen Gaeumannomyces graminis var. tritici, for which two coexisting but genetically distinct types and a trade-off related to seasonality in host presence have been identified. Numerical simulations are used to show that a trade-off between the pathogen transmission rate and the survival of the pathogen between cropping seasons cannot account for the evolutionary branching observed in many pathogens. Model elaborations show that this conclusion holds for a broad range of putative mechanisms. Although the analysis is motivated and illustrated by the specific example of take-all of wheat, the results apply to a broad range of pathogens.

scholarly journals Control of seed borne fungi on tomato seeds and their management by botanical extracts

2016 ◽  
Vol 3 (3) ◽  
pp. 403-410 ◽  
Author(s):  
Imam Mehedi ◽  
Afia Sultana ◽  
Md Amanut Ullah Raju
Keyword(s):  
Fungal Species ◽  
Leaf Extracts ◽  
Tomato Seeds ◽  
Seed Health ◽  
The Status ◽  
Significant Performance ◽  
Seed Health Test ◽  
Aspergillus Sp ◽  
Health Test ◽  
Different Doses

Seed health test was done in laboratory to determine the status of seed borne fungi on seeds of five tomato (Lycopersicon esculentum) varieties viz. Manik, Ratan, Roma VF, Kopotakkho and Monirumpuri and their possible control by using plant extracts. A total of 4 genera of 3 species of fungi were recorded where Fusarium oxysporum was the most prevalent and predominant seed borne fungus (25.60%). Other three fungal species are Aspergillus sp. of Aspergillus flavus (21.70%) and Aspergillus niger (11.11%) and Cladosporium sp. (13.49%). Tomato seeds were treated with different plant leaf extracts namely Mahogany, Mehendi and Allamanda with different doses viz. 1:1, 1:2 and 1:3 to control the seed borne fungi. In treated seeds, germination was ranged from 72-82% which was 68% in controlled condition. Among the doses of three botanicals, Mahogany, Mehendi and Allamonda extract @ (1:1 w/v) showed significant performance in controlling seed borne fungi and germination of tomato seeds. Among the three botanicals, Mahogany @ (1:1 w/v) was found the best treatment regarding percent reduction of seed borne infection.Res. Agric., Livest. Fish.3(3): 403-410, December 2016

scholarly journals Effect of Spaceflight on Tomato Seed Quality and Biochemical Characteristics of Mature Plants

Horticulturae ◽  
2021 ◽  
Vol 7 (5) ◽  
pp. 89
Author(s):  
Elena Dzhos ◽  
Nadezhda Golubkina ◽  
Marina Antoshkina ◽  
Irina Kondratyeva ◽  
Andrew Koshevarov ◽  
...  
Keyword(s):  
Seed Quality ◽  
Space Station ◽  
Field Conditions ◽  
Tomato Seed ◽  
Tomato Plants ◽  
Biochemical Characteristics ◽  
Tomato Seeds ◽  
Genetic Modifications ◽  
Total Antioxidant

Intensive space exploration includes profound investigations on the effect of weightlessness and cosmic radiation on plant growth and development. Tomato seeds are often used in such experiments though up to date the results have given rather vague information about biochemical changes in mature plants grown from seeds subjected to spaceflight. The effect of half a year of storage in the International Space Station (ISS) on tomato seeds (cultivar Podmoskovny ranny) was studied by analyzing the biochemical characteristics and mineral content of mature plants grown from these seeds both in greenhouse and field conditions. A significant increase was recorded in ascorbic acid, polyphenol and carotenoid contents, and total antioxidant activity (AOA), with higher changes in the field conditions compared to greenhouse. Contrary to control plants, the ones derived from space-stored seeds demonstrated a significant decrease in root AOA. The latter plants also showed a higher yield, but lower content of fruit dry matter, sugars, total dissolved solids and organic acids. The fruits of plants derived from space-stored seeds demonstrated decreased levels of Fe, Cu and taste index. The described results reflect the existence of oxidative stress in mature tomato plants as a long-term consequence of the effect of spaceflight on seed quality, whereas the higher yield may be attributed to genetic modifications.

scholarly journals A Graft-Based Chemotherapy Method for Screening Effective Molecules and Rescuing Huanglongbing-Affected Citrus Plants

2012 ◽  
Vol 102 (6) ◽  
pp. 567-574 ◽  
Author(s):  
Muqing Zhang ◽  
Charles A. Powell ◽  
Ying Guo ◽  
Melissa S. Doud ◽  
Yongping Duan
Keyword(s):  
Survival Rate ◽  
Transmission Rate ◽  
High Titer ◽  
Critical Factor ◽  
Transmission Efficiency ◽  
Pathogen Transmission ◽  
Citrus Industry ◽  
Chemical Treatments ◽  
Bacterial Titer ◽  
Transmission Studies

Huanglongbing (HLB) is the most devastating disease of citrus. The global citrus industry is in urgent need of effective chemical treatments for HLB control because of its rapid spreading worldwide. Due to the fastidious nature of the pathogens, and the poor permissibility of citrus leaf surfaces, effective screening of chemicals for the HLB control can be challenging. In this study, we developed a graft-based chemotherapy method to rapidly screen potential HLB-controlling chemical compounds. In addition, we improved transmission efficiency by using the best HLB-affected scion–rootstock combination, and demonstrated the HLB bacterial titer was the critical factor in transmission. The HLB-affected lemon scions had a high titer of HLB bacterium, survival rate (83.3%), and pathogen transmission rate (59.9%). Trifoliate, a widely used commercial rootstock, had the highest survival rate (>70.0%) compared with grapefruit (52.6%) and sour orange (50.4%). Using this method, we confirmed a mixture of penicillin and streptomycin was the most effective compounds in eliminating the HLB bacterium from the HLB-affected scions, and in successfully rescuing severely HLB-affected citrus germplasms. These findings are useful not only for chemical treatments but also for graft-based transmission studies in HLB and other Liberibacter diseases.

scholarly journals A computationally tractable birth-death model that combines phylogenetic and epidemiological data

2020 ◽  
Author(s):  
Alexander E. Zarebski ◽  
Louis du Plessis ◽  
Kris V. Parag ◽  
Oliver G. Pybus
Keyword(s):  
Transmission Rate ◽  
Epidemiological Data ◽  
Heterogeneous Data ◽  
Pathogen Transmission ◽  
Data Sources ◽  
Primary Data ◽  
Analytic Approximation ◽  
Data Set ◽  
Combining Data ◽  
Birth Death

Inferring the dynamics of pathogen transmission during an outbreak is an important problem in both infectious disease epidemiology and phylodynamics. In mathematical epidemiology, estimates are often informed by time-series of infected cases while in phylodynamics genetic sequences sampled through time are the primary data source. Each data type provides different, and potentially complementary, insights into transmission. However inference methods are typically highly specialised and field-specific. Recent studies have recognised the benefits of combining data sources, which include improved estimates of the transmission rate and number of infected individuals. However, the methods they employ are either computationally prohibitive or require intensive simulation, limiting their real-time utility. We present a novel birth-death phylogenetic model, called TimTam which can be informed by both phylogenetic and epidemiological data. Moreover, we derive a tractable analytic approximation of the TimTam likelihood, the computational complexity of which is linear in the size of the data set. Using the TimTam we show how key parameters of transmission dynamics and the number of unreported infections can be estimated accurately using these heterogeneous data sources. The approximate likelihood facilitates inference on large data sets, an important consideration as such data become increasingly common due to improving sequencing capability.

scholarly journals Higher Variability in Fungi Compared to Bacteria in the Foraging Honey Bee Gut

2020 ◽  
Author(s):  
Leslie E. Decker ◽  
Priscilla A. San Juan ◽  
Magdalena L. Warren ◽  
Cory E. Duckworth ◽  
Cheng Gao ◽  
...  
Keyword(s):  
Species Composition ◽  
Microbial Communities ◽  
Honey Bee ◽  
Honey Bees ◽  
Plant Pathogens ◽  
Distribution Patterns ◽  
Model System ◽  
Pathogen Transmission ◽  
Host Health ◽  
Gut Symbionts

AbstractMicrobial communities in the honey bee gut have emerged as a model system to understand the effects of host-associated microbes on animals and plants. The specific distribution patterns of bacterial associates among honey bee gut regions remains a key finding within the field. The mid- and hindgut of foraging bees house a deterministic set of core species that affect host health. In contrast, the crop, or honey stomach, contains a more diverse set of bacteria that is highly variable in composition among individual bees. Whether this contrast between the two gut regions also applies to fungi, another major group of gut-associated microbes, remains unclear despite their potential influence on host health. In honey bees caught foraging at four sites across the San Francisco Peninsula, we found that fungi were much less distinct in species composition between the crop and the mid- and hindgut than bacteria. Unlike bacteria, fungi were highly variable in composition throughout the gut, and much of this variation was attributable to bee collection site. These patterns suggest that the fungi may be passengers rather than functionally significant gut symbionts. However, many of the fungi we found in the bees have been recognized as plant pathogens. Assuming that some fungi remain viable after passage through the gut, the distribution patterns we report here point to the potential importance of honey bees as vectors of fungal pathogens and suggest a more prominent role of honey bees in plant pathogen transmission than generally thought.Importance (Nontechnical explanation of why the work was undertaken)Along with bacteria, fungi make up a significant portion of animal- and plant-associated microbial communities. However, we have only begun to describe these fungi, much less examine their effects on most animals and plants. The honey bee, Apis mellifera, has emerged as a model system for studying host-associated microbes. Honey bees contain well-characterized bacteria specialized to inhabit different regions of the gut. Fungi also exist in the honey bee gut, but their composition and function remain largely undescribed. Here we show that, unlike bacteria, fungi vary substantially in species composition throughout the honey bee gut, contingent on where the bees are sampled. This observation suggests that fungi may be transient passengers and therefore unimportant as gut symbionts. However, our findings also indicate that honey bees could be major vectors of infectious plant diseases as many of the fungi we found in the honey bee gut are recognized as plant pathogens.

Evaluation of droplet digital PCR for the detection of black canker disease in tomato

Plant Disease ◽  
2021 ◽  
Author(s):  
Li Wang ◽  
Tian Qian ◽  
Pei Zhou ◽  
Wenjun Zhao ◽  
Xianchao Sun
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Plant Pathogens ◽  
Plant Protection ◽  
Detection Threshold ◽  
Digital Pcr ◽  
Taqman Probe ◽  
Tomato Seed ◽  
Canker Disease ◽  
Probe Set

Clavibacter michiganensis subsp. michiganensis (Cmm), the cause of bacterial canker disease, is one of the most destructive pathogens in greenhouse and field tomato. The pathogen is now present in all main production areas of tomato and is quite widely distributed in the EPPO（European and Mediterranean Plant Protection Organization）region. The inspection and quarantine of the plant pathogens relies heavily on accurate detection tools. Primers and probes reported in previous studies do not distinguish the Cmm pathogen from other closely related subspecies of C. michiganensis, especially the non-pathogenic subspecies that were identified from tomato seeds recently. Here, we have developed a droplet digital polymerase chain reaction (ddPCR) method for the identification of this specific bacterium with primers/TaqMan probe set designed based on the pat-1 gene of Cmm. This new primers/probe set has been evaluated by qPCRthe real time PCR（qPCR） and ddPCR. The detection results suggest that the ddPCR method established in this study was highly specific for the target strains. The result showed the positive amplification for all 5 Cmm strains，and no amplification was observed for the other 43 tested bacteria, including the closely related C. michiganensis strains. The detection threshold of ddPCR was 10.8 CFU/mL for both pure Cmm cell suspensions and infected tomato seed, which was 100 times-fold more sensitive than that of the real-time PCR (qPCR ) performed using the same primers and probe. The data obtained suggest that our established ddPCR could detect Cmm even with low bacteria load, which could facilitate both Cmm inspection for pathogen quarantine and the routine pathogen detection for disease control of black canker in tomato.

scholarly journals Effect of Seed Priming with Potassium Nitrate on the Performance of Tomato

Agriculture ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 498
Author(s):  
Muhammad Moaaz Ali ◽  
Talha Javed ◽  
Rosario Paolo Mauro ◽  
Rubab Shabbir ◽  
Irfan Afzal ◽  
...  
Keyword(s):  
Crop Production ◽  
Soluble Sugars ◽  
Seed Priming ◽  
Potassium Nitrate ◽  
Poor Quality ◽  
Growth Chamber ◽  
Tomato Seed ◽  
Tomato Seeds ◽  
Plant Growth Promoting ◽  
Greenhouse Screening

The seed industry and farmers have challenges, which include the production of poor quality and non-certified tomato seed, which ultimately results in decreased crop production. The issue carefully demands pre-sowing treatments using exogenous chemical plant growth-promoting substances. Therefore, to mitigate the above-stated problem, a series of experiments were conducted to improve the quality of tomato seeds (two cultivars, i.e., “Sundar” and “Ahmar”) and to enhance the stand establishment, vigor, physiological, and biochemical attributes under growth chamber and greenhouse conditions by using potassium nitrate (KNO3) as a seed priming agent. Seeds were imbibed in 0.25, 0.50, 0.75, 1.0, and 1.25 KNO3 (weight/volume) for 24 h and then dried before experiments. The results of growth chamber and greenhouse screening show that experimental units receiving tomato seeds primed with 0.75% KNO3 in both cultivars performed better as compared to other concentrations and nonprimed control. Significant increase in final emergence (%), mean emergence time, and physiological attributes were observed with 0.75% KNO3. Collectively, the improved performance of tomato due to seed priming with 0.75% KNO3 was linked with higher activities of total soluble sugars and phenolics under growth chamber and greenhouse screening.

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