scholarly journals Production Steps to Reduce Seed Contamination by Pathogens of Cucurbits

2003 ◽  
Vol 13 (1) ◽  
pp. 50-54 ◽  
Author(s):  
Branko R. Lovic ◽  
Donald L. Hopkins
Keyword(s):  
Seed Production ◽  
Continuous Monitoring ◽  
Pathogenic Bacteria ◽  
Significant Risk ◽  
Disease Symptoms ◽  
Bacterial Fruit Blotch ◽  
Seed Harvest ◽  
Bacteria And Fungi ◽  
Production Areas ◽  
Disease Pressure

Selecting production areas for low disease pressure, implementation of preventive spray programs, and continuous monitoring for disease symptoms are important steps to keep seed production fields free of potentially seedborne diseases, such as bacterial fruit blotch of cucurbits (Cucurbitaceae), caused by Acidovorax avenae ssp. citrulli. However, seeds of cucurbit crops and other fleshy vegetables typically remain remarkably free of pathogenic bacteria and fungi while in intact fruit. The most significant risk for seed contamination comes at harvest when the inoculum present in the field or in the seed harvesting area may contaminate the seeds. Properly executed fermentation and seed drying processes significantly reduce seed contamination. Application of a no-rinse disinfectant formulation to freshly harvested seed just before drying may be the single most efficacious procedure to reduce the seed contamination risk. However, the disinfection step should not be expected to be effective unless applied as part of a fully controlled seed harvest process.

scholarly journals Prevalence of Acidovorax citrulli in Commercial Cucurbit Seedlots During 2010–2018 in China

Plant Disease ◽  
2020 ◽  
Vol 104 (1) ◽  
pp. 255-259 ◽  
Author(s):  
Yanli Tian ◽  
Yuqiang Zhao ◽  
Jiaju Zhou ◽  
Ting Sun ◽  
Xue Luo ◽  
...  
Keyword(s):  
Seed Production ◽  
Inner Mongolia ◽  
Fruit Production ◽  
Colony Pcr ◽  
Primary Inoculum ◽  
Bacterial Fruit Blotch ◽  
Growing Seasons ◽  
Acidovorax Citrulli ◽  
High Prevalence ◽  
Production Areas

Acidovorax citrulli is the causal agent of bacterial fruit blotch (BFB), a serious threat to cucurbit fruit and seed production worldwide. In recent years, the BFB has spread to many areas of China, mainly via the inadvertent distribution of contaminated commercial seeds. To assess the prevalence of seedborne A. citrulli in commercial watermelon and other cucurbitaceous seedlots in China, a 9-year survey was conducted between 2010 and 2018. A total of 4,839 seedlots of watermelon and other cucurbitaceous species were collected from 13 major seed production areas of China and tested by a semiselective media-based colony PCR technique for A. citrulli. Overall, A. citrulli was detected in 18.00% (871/4,839) of all cucurbitaceous seedlots. The bacterium was detected in 21.59% (38/176), 19.19% (33/172), 23.44% (214/913), 40.76% (247/606), 13.28% (85/640), 15.40% (95/617), 13.25% (73/551), 8.03% (48/598), and 6.71% (38/566) of all commercial seedlots tested from the 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, and 2018 growing seasons, respectively. Additionally, the prevalence of A. citrulli in cucurbit seedlots was determined for different seed production areas. The prevalence of A. citrulli in cucurbitaceous seedlots produced in Xinjiang, Gansu, Ningxia, Inner Mongolia, and 9 other provinces was 18.76% (582/3103), 26.34% (103/391), 21.47% (82/382), 11.11% (14/126), and 10.75% (90/837), respectively. This is the first survey for A. citrulli in commercial cucurbit seeds in China, and the relatively high prevalence suggests that commercial seeds represent a substantial source of primary inoculum that can threaten cucurbit seed and fruit production in China.

Students personality professional and applied physical culture formation (on the example of librarianship specialists)

2020 ◽  
pp. 166-175
Author(s):  
Yana V. Platonova ◽  
Alexander N. Sisoev
Keyword(s):  
Pathogenic Bacteria ◽  
Occupational Safety ◽  
Vision Loss ◽  
Negative Impact ◽  
Significant Risk ◽  
Influenza Viruses ◽  
Burnout Syndrome ◽  
Professional Activity ◽  
Negative Consequences ◽  
Bacteria And Fungi

We analyze the most frequently encountered problems in the field of occupational hazards of library workers. Negative consequences of influence of professional work in the library is the nervous system overvoltage appearance, leading to internal emotional exhaustion and “emotional burnout” syndrome; the development of physical inactivity, leading to irregular functioning of the musculoskeletal and cardiovascular systems of workers; fatigue occurrence and vision loss in the process for a personal computer. In addition, the main activity of the librarian is carried out in paper and book dust negative impact conditions, the presence of pathogenic bacteria and fungi in the microflora, non-compliance of microclimate parameters in the premises of libraries with the required standards. A serious risk to which librarians are exposed in their workplaces is associated with the respiratory diseases development, which may be allergic in nature (bronchial asthma) or airborne transmission (tuberculosis, influenza viruses). The results of lung capacity testing, breathe retention time on inhalation and exhalation of female students of 1–2 courses of the Culture and Arts Faculty of Derzhavin Tambov State University allow us to reveal a picture of the respiratory system functional state, exposed to significant risk in the professional activity process of the library sphere employee. Knowledge and skills system formation related to occupational safety, health, library workers certain diseases prevention should be laid in the period of study at the university, including physical education.

Natural establishment of Pinus spp. around seed production areas and orchards

2021 ◽  
Vol 494 ◽  
pp. 119333
Author(s):  
Magda Paula dos Santos ◽  
Marcio José de Araujo ◽  
Paulo Henrique Müller da Silva
Keyword(s):  
Seed Production ◽  
Natural Establishment ◽  
Pinus Spp ◽  
Production Areas

scholarly journals Seasonal Variation Characteristics of Bacteria and Fungi in PM2.5 in Typical Basin Cities of Xi’an and Linfen, China

Atmosphere ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 809
Author(s):  
Sen Wang ◽  
Wanyu Liu ◽  
Jun Li ◽  
Haotian Sun ◽  
Yali Qian ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
Relative Abundance ◽  
Pathogenic Bacteria ◽  
High Throughput Sequencing ◽  
Fine Particulate Matter ◽  
Ecological Functions ◽  
Factors Affecting ◽  
Bacterial Phyla ◽  
Variation Characteristics ◽  
Bacteria And Fungi

Microorganisms existing in airborne fine particulate matter (PM2.5) have key implications in biogeochemical cycling and human health. In this study, PM2.5 samples, collected in the typical basin cities of Xi’an and Linfen, China, were analyzed through high-throughput sequencing to understand microbial seasonal variation characteristics and ecological functions. For bacteria, the highest richness and diversity were identified in autumn. The bacterial phyla were dominated by Proteobacteria, Actinobacteria, Firmicutes, and Bacteroidetes. Metabolism was the most abundant pathway, with the highest relative abundance found in autumn. Pathogenic bacteria (Pseudomonas, Acinetobacter, Serratia, and Delftia) were positively correlated with most disease-related pathways. Besides, C cycling dominated in spring and summer, while N cycling dominated in autumn and winter. The relative abundance of S cycling was highest during winter in Linfen. For fungi, the highest richness was found in summer. Basidiomycota and Ascomycota mainly constituted the fungal phyla. Moreover, temperature (T) and sulfur dioxide (SO2) in Xi’an, and T, SO2, and nitrogen dioxide (NO2) in Linfen were the key factors affecting microbial community structures, which were associated with different pollution characteristics in Xi’an and Linfen. Overall, these results provide an important reference for the research into airborne microbial seasonal variations, along with their ecological functions and health impacts.

scholarly journals Antimicrobial Activities of Marine Sponge-Associated Bacteria

2021 ◽  
Vol 9 (1) ◽  
pp. 171
Author(s):  
Yitayal S. Anteneh ◽  
Qi Yang ◽  
Melissa H. Brown ◽  
Christopher M. M. Franco
Keyword(s):  
Pathogenic Bacteria ◽  
South Australia ◽  
Multidrug Resistant ◽  
Antimicrobial Activities ◽  
Marine Sponges ◽  
Bioactive Metabolites ◽  
Human Pathogens ◽  
Sponge Associated Bacteria ◽  
Microbial Symbionts ◽  
Bacteria And Fungi

The misuse and overuse of antibiotics have led to the emergence of multidrug-resistant microorganisms, which decreases the chance of treating those infected with existing antibiotics. This resistance calls for the search of new antimicrobials from prolific producers of novel natural products including marine sponges. Many of the novel active compounds reported from sponges have originated from their microbial symbionts. Therefore, this study aims to screen for bioactive metabolites from bacteria isolated from sponges. Twelve sponge samples were collected from South Australian marine environments and grown on seven isolation media under four incubation conditions; a total of 1234 bacterial isolates were obtained. Of these, 169 bacteria were tested in media optimized for production of antimicrobial metabolites and screened against eleven human pathogens. Seventy bacteria were found to be active against at least one test bacterial or fungal pathogen, while 37% of the tested bacteria showed activity against Staphylococcus aureus including methicillin-resistant strains and antifungal activity was produced by 21% the isolates. A potential novel active compound was purified possessing inhibitory activity against S. aureus. Using 16S rRNA, the strain was identified as Streptomyces sp. Our study highlights that the marine sponges of South Australia are a rich source of abundant and diverse bacteria producing metabolites with antimicrobial activities against human pathogenic bacteria and fungi.

scholarly journals First Report of Umbel Browning and Stem Necrosis Caused by Diaporthe angelicae on Carrot in France

Plant Disease ◽  
2014 ◽  
Vol 98 (3) ◽  
pp. 421-421 ◽  
Author(s):  
L. Ménard ◽  
P. E. Brandeis ◽  
P. Simoneau ◽  
P. Poupard ◽  
I. Sérandat ◽  
...  
Keyword(s):  
Seed Production ◽  
White Light ◽  
Agar Medium ◽  
Malt Agar ◽  
Universal Primers ◽  
Conidial Suspension ◽  
First Report ◽  
Daucus Carota L ◽  
Cropping Seasons ◽  
Production Areas

In 2011, carrot (Daucus carota L.) seed production occurred on 2,900 ha, which accounts for approximately 25% of the area devoted to the production of vegetable fine seeds. Since 2007, symptoms of umbel browning have been regularly observed in carrot production areas located in the central region. Initially, triangular necrotic lesions appeared on carrot umbels that later spread to the entire umbels and often progressed to the stems. Diseased umbels became dried prematurely, compromising seed development. The loss in seed production was estimated at approximately 8% of the harvested carrot umbels during the cropping seasons of spring and summer 2007 and 2008 in France. In collaboration with seed companies, diseased carrot stems were collected from seven fields of seed production (eight plants per field) and a fungus was isolated from the tissue. The cultures were grown on malt (2%) agar (1.5%) medium and incubated for 2 weeks at 22°C in darkness. Young fungal colonies were white and a brownish green pigmentation developed when the colonies became older. The same color was observed from the top and on the reverse of the colonies. To induce sporulation, isolates were grown on water agar (1.5%) medium in the presence of carrot stem fragments for 1 week at 22°C in darkness, followed by 1 week at 22°C in white light under a 16-h photoperiod. Pycnidia were produced on stem fragments and contained alpha and beta conidia typical of the genus Diaporthe (2). Alternatively, pycnidia were also obtained on malt agar medium after 2 weeks of culture at 25°C in white light under a 12-h photoperiod. The size of alpha and beta conidia was 6.3 ± 0.5 × 2.3 ± 0.4 μm and 23.3 ± 1.8 × 0.9 ± 0.2 μm, respectively (n = 170). In order to confirm the identification at the genus level and determine the species, DNA was extracted from the mycelium of three representative isolates and the ITS regions of the ribosomal DNA were amplified using universal primers (1). The sequences of the amplified products (GenBank Accession Nos. KF240772 to KF240774) were 100% identical with the ITS sequence of a Diaporthe angelicae isolate deposited in the NCBI database (CBS 111592 isolate, KC343027). To confirm pathogenicity, the three isolates of D. angelicae were inoculated on carrot umbels in the greenhouse. A total of nine plants were inoculated (three plants per isolate). Using a micropipette, 10 μl of a conidial suspension containing alpha and beta conidia (105 conidia mL–1) were deposited at the base of the primary umbel and two secondary umbels, which were wounded before inoculation using a scalpel blade. Seven inoculated plants developed triangular, necrotic lesions that were typical umbel browning. D. angelicae was re-isolated on malt agar medium from the inoculated diseased carrot umbels. To our knowledge, this is the first report of D. angelicae in carrot cultivated for seed production in France. The disease resembles the lesions described in the Netherlands in 1951 on carrot inflorescence caused by Phomopsis dauci (3). In future experiments, it would be crucial to precisely determine if D. angelicae could be transmitted to the seeds. References: (1) M. A. Innis et al. PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, CA, 1990. (2) J. M. Santos and A. J. L. Philips. Fungal Divers. 34:111, 2009. (3) J. A. von Arx. Eur. J. Plant Pathol. 57:44, 1951.

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