scholarly journals Evidence for Systemic Infection by Puccinia horiana, Causal Agent of Chrysanthemum White Rust, in Chrysanthemum

2015 ◽  
Vol 105 (1) ◽  
pp. 91-98 ◽  
Author(s):  
M. R. Bonde ◽  
C. A. Murphy ◽  
G. R. Bauchan ◽  
D. G. Luster ◽  
C. L. Palmer ◽  
...  
Keyword(s):  
United States ◽  
Cell Walls ◽  
Vascular Tissue ◽  
Mesophyll Cell ◽  
The United States ◽  
Causal Agent ◽  
Control Measures ◽  
Mesophyll Cells ◽  
White Rust ◽  
Puccinia Horiana

Puccinia horiana, causal agent of the disease commonly known as chrysanthemum white rust (CWR), is a quarantine-significant fungal pathogen of chrysanthemum in the United States and indigenous to Asia. The pathogen was believed to have been eradicated in the United States but recently reappeared on several occasions in northeastern United States. The objective of the study presented here was to determine whether P. horiana could systemically infect chrysanthemum plants, thus providing a means of survival through winters. Scanning and transmission electron microscopy revealed the development of P. horiana on the surface and within leaves, stems, or crowns of inoculated chrysanthemum plants artificially exposed to northeastern U.S. winter temperatures. P. horiana penetrated leaves directly through the cuticle and then colonized the mesophyll tissue both inter- and intracellularly. An electron-dense material formed at the interface between fungal and host mesophyll cells, suggesting that the pathogen adhered to the plant cells. P. horiana appeared to penetrate mesophyll cell walls by enzymatic digestion, as indicated by the absence of deformation lines in host cell walls at penetration sites. The fungus was common in vascular tissue within the infected crown, often nearly replacing the entire contents of tracheid cell walls. P. horiana frequently passed from one tracheid cell to an adjacent tracheid cell by penetration either through pit pairs or nonpitted areas of the cell walls. Individual, presumed, fungal cells in mature tracheid cells of the crown and stems arising from infected crowns suggested that the pathogen might have been moving at least partially by means of the transpiration stream. The demonstration that chrysanthemum plants can be systemically infected by P. horiana suggests that additional disease control measures are required to effectively control CWR.

scholarly journals First Confirmed Report that Puccinia horiana, Causal Agent of Chrysanthemum White Rust, Can Overwinter in Pennsylvania

Plant Disease ◽  
2012 ◽  
Vol 96 (9) ◽  
pp. 1381-1381 ◽  
Author(s):  
G. O'Keefe ◽  
D. D. Davis
Keyword(s):  
United States ◽  
Molecular Analysis ◽  
Tap Water ◽  
Signs And Symptoms ◽  
The United States ◽  
Causal Agent ◽  
Controlled Environment ◽  
White Rust ◽  
Environment Chamber ◽  
Puccinia Horiana

Chrysanthemum white rust (CWR) is a quarantine-significant pest in the United States (Title 7, Code of Federal Regulations, Part 319.37-2). The causal agent of CWR, Puccinia horiana Henn., is an autoecious, microcyclic rust that is pathogenic on chrysanthemum species (Chrysanthemum spp.) and close relatives within the family Asteraceae. CWR is indigenous to Japan, where it was first reported in 1895 (4). By the 1960s, CWR was found throughout Europe and later spread to Africa, Oceana, South America, and other parts of Asia. In North America, CWR was reported in Mexico and in the United States (New Jersey and Pennsylvania [1977], Oregon and Washington [1990], and California [1991]). Additional detections of CWR were later reported in 22 Pennsylvania counties (2004, 2006 to 2010) (3). These later Pennsylvania reports stated that eradication was attempted at some sites, but unconfirmed observations suggested that the rust pathogen might overwinter in volunteer plants (3). Since “CWR is known to overwinter in Europe where chrysanthemums overwinter (average minimum temperatures ranging from –10°F to 10°F)” (2), the unconfirmed Pennsylvania observations prompted us to determine if P. horiana can overwinter in Pennsylvania. During October 2010, we identified CWR on perennial mums planted at six outdoor garden locations in University Park, PA. Symptomatic plants were quarantined and eradication attempted. Eradicated sites were routinely surveyed and CWR confirmed in July 2011 on volunteer plants at two of the originally infested sites. An additional outdoor garden site with CWR was observed in State College, PA, during October 2011 and eradication attempted. The three infested sites were surveyed throughout the fall and winter of 2011 to 2012. During February 2012, two asymptomatic volunteer plants arising from root pieces were collected from each of the three sites. Each sample was washed with tap water to remove excess soil, examined morphologically, surface sterilized with 10% bleach, and divided into two subsamples. One subsample from each site was divided into crown and root portions and DNA extracted using a Qiagen DNeasy Plant Mini Kit. Molecular analysis was performed using modifications of published primers ITS 5 and Rust1 (1,4). Puccinia horiana was detected in plant roots from one site and in plant crowns from two sites. The remaining two subsamples from each site were transplanted into sterilized potting soil and placed in a clean controlled environment chamber at 18°C and 85% relative humidity (RH). After 6 weeks, six actively growing plants were transferred to a second clean controlled environment chamber at 17°C and 90 to 100% RH. On 6 April 2012, CWR symptoms and signs were confirmed morphologically on two plants that had been removed from one site. On 19 April 2012, CWR signs and symptoms were confirmed morphologically and by molecular analysis on leaves of volunteer plants at one University Park site. DNA extractions were sequenced and shared a 100% maximum identity to a known P. horiana accession (EU816920.1) in GenBank. To our knowledge, this is the first confirmed report of P. horiana overwintering in Pennsylvania. References: (1) H. Alaei et al. Mycol. Res. 113:668, 2009. (2) Anon. Chrysanthemum White Rust Bulletin, Syngenta Flowers Inc., Gilroy, CA, 2010. (3) S. Kim et al. Phytopathology 101:S91, 2011. (4) K. Pedley. Plant Dis. 93:1252, 2009.

Sporulation Capacity and Longevity of Puccinia horiana Teliospores in Infected Chrysanthemum Leaves

2013 ◽  
Vol 14 (1) ◽  
pp. 11 ◽  
Author(s):  
Morris R. Bonde ◽  
Cristi L. Palmer ◽  
Douglas G. Luster ◽  
Susan E. Nester ◽  
Jason M. Revell ◽  
...  
Keyword(s):  
United States ◽  
Fungal Pathogen ◽  
Local Environment ◽  
The United States ◽  
First Report ◽  
White Rust ◽  
Teliospore Germination ◽  
Sporulation Capacity ◽  
Leaf Necrosis ◽  
Puccinia Horiana

Puccinia horiana Henn., a quarantine-significant fungal pathogen and causal agent of chrysanthemum white rust (CWR), was first discovered in the United States in 1977 and later believed to have been eradicated. Recently, however, the disease has sporadically reappeared in the northeastern US. Possible explanations for the reappearance include survival of the pathogen in the local environment, and reintroduction from other locations. To determine the possibility that the pathogen might be overwintering in the field, we undertook the study described here. Results from the study showed that P. horiana teliospores, imbedded in infected leaves, were capable of sporulating 2 weeks after inoculation, and this capacity continued until the leaf became necrotic and desiccated. This is the first report of the extreme susceptibility of P. horiana teliospores to leaf necrosis and desiccation and suggests that field infections following winter are unlikely to originate from teliospores. Teliospore germination on excised leaves was shown to be inhibited by light. Accepted for publication 3 April 2013. Published 23 August 2013.

Viability of Puccinia horiana Teliospores Under Various Environmental Conditions

2014 ◽  
Vol 15 (1) ◽  
pp. 25-28 ◽  
Author(s):  
Morris R. Bonde ◽  
Cristi L. Palmer ◽  
Douglas G. Luster ◽  
Susan E. Nester ◽  
Jason M. Revell ◽  
...  
Keyword(s):  
United States ◽  
Fungal Pathogen ◽  
The United States ◽  
Northeastern United States ◽  
Plant Debris ◽  
White Rust ◽  
Winter Conditions ◽  
Dry Soil ◽  
Puccinia Horiana ◽  
Sensitive Method

Puccinia horiana Henn. is a quarantine-significant fungal pathogen and causal agent of chrysanthemum white rust (CWR). The pathogen and disease were first discovered in the United States in 1977 and quickly eradicated. During the early 1990s, CWR reemerged in several instances, but in each instance was declared eradicated. However, since approximately 2004 CWR has reappeared at an accelerated frequency. This has suggested that either P. horiana is entering the country more frequently from foreign locations or that P. horiana is now established in the field, implying that spores are capable of surviving winter conditions in plant debris or soil. As a result of the possibility that the pathogen has become established in the United States, we initiated several lines of research. The objectives of the study reported here were: (i) develop a better and more sensitive method to measure teliospore longevity; and (ii) determine if the pathogen is able to survive northeastern winters as viable teliospores. Results from the study showed that teliospores survived in the greenhouse a maximum of 28 days in dry soil and 7 days in moist soil. In a growth chamber simulating winter temperature conditions in the northeastern United States, teliospores survived a maximum of 35 days. It was concluded that P. horiana teliospores are not able to survive through typical northeastern U.S. winters. Accepted for publication 9 January 2014. Published 18 March 2014.

scholarly journals First Report of the Presence of Albugo tragopogonis on Cineraria maritima in Italy

Plant Disease ◽  
2003 ◽  
Vol 87 (4) ◽  
pp. 450-450 ◽  
Author(s):  
A. Garibaldi ◽  
A. Minuto ◽  
D. Bertetti ◽  
M. L. Gullino
Keyword(s):  
United States ◽  
Average Diameter ◽  
The United States ◽  
Causal Agent ◽  
Adaxial Surface ◽  
First Report ◽  
White Rust ◽  
Plastic Bags ◽  
Commercial Farms ◽  
Cineraria Maritima

Cineraria maritima L. (synonym Senecio cineraria DC.), commonly known as dusty-miller, is grown in Italy for landscape use in parks and gardens. In the spring of 2001, severe outbreaks of a previously unknown disease were observed in commercial farms located in northern Italy. Leaves of infected plants showed several sori on the abaxial surface, progressing to the adaxial surface, and often in the interveinal areas. On the adaxial surface of leaves, chlorotic areas developed and eventually turned brown. Severely infected leaves wilted, but remained attached to the stem. Signs of the fungus were present as whitish and catenulate sporangia emerging from the sori. Sporangia, organized in chains, had an average diameter of 20.5 × 26.5 μm. On the basis of the microscopic observations, the causal agent of the disease was identified as Albugo tragopogonis. Pathogenicity was confirmed by inoculating leaves of healthy C. maritima plants with a sporangial suspension (5 × 102 sporangia per ml) obtained from infected plants. Noninoculated plants served as a control. Plants were kept covered with plastic bags for 72 h and maintained at 15°C. After 10 days, typical symptoms of white rust developed on inoculated plants starting from the basal leaves. Within 30 days, affected leaves were completely wilted. Microscopic examination of sporangia within sori verified the pathogen to be A. tragopogonis. No symptoms developed on the control plants. A. tragopogonis has been reported as the causal agent of white rust on several species belonging to the genus Senecio in the United States (1). In New Zealand, the presence of A. tragopogonis was reported on the genus Cineraria in 1959 (2). To our knowledge, this is the first report of the presence of white rust on Cineraria maritima in Italy. References: (1) D. F. Farr et al. Fungi on Plants and Plant Products in the United States. The American Phytopathological Society, St Paul, MN, 1989. (2) J. M. Dingley. N. Z. J. Agric. Res. 2:380, 1959.

The leaf anatomy of beech, Fagus grandifolia

1975 ◽  
Vol 53 (19) ◽  
pp. 2202-2211 ◽  
Author(s):  
Nancy G. Dengler ◽  
Lynette B. MacKay
Keyword(s):  
Surface Area ◽  
Cell Walls ◽  
Vascular Tissue ◽  
Leaf Surface ◽  
Mesophyll Cell ◽  
Fagus Grandifolia ◽  
Mesophyll Cells ◽  
Surface Areas ◽  
Leaf Surface Area ◽  
Leaf Volume

Observations have been made on the anatomy of beech, Fagus grandifolia Ehrh., with an emphasis on quantitative features. All surface areas and volumes were determined by projecting 2-μm serial sections, measuring them with a map tracer, and multiplying cell perimeters by section thickness or by the trace–cut–weight method. The organization of tissues, including a complex reticulate venation, is typical of many dicotyledons. Of the minor veins, only the quinternaries and veinlets lack bundle sheath extensions and have wholly parenchymatous bundle sheaths, the cells of which are often oriented at right angles to the vein. There are 12.1 mm of vein per square millimetre of leaf surface area, and 10 μm of vein (the diameter of a mesophyll cell) serves about 21.5 mesophyll cells. The mean maximum distance over which water and solutes must move between vascular tissue and mesophyll is 55 μm. The mesophyll cell walls may provide the pathway through which the bulk of the water moves; the volume occupied by the mesophyll cell walls is 55.7 mm3 or 11% of total leaf volume. The evaporative surface of the mesophyll is 13.36 mm2/mm2 leaf surface area.

scholarly journals Estimated transmissibility and impact of SARS-CoV-2 lineage B.1.1.7 in England

Science ◽  
2021 ◽  
Vol 372 (6538) ◽  
pp. eabg3055 ◽  
Author(s):  
Nicholas G. Davies ◽  
Sam Abbott ◽  
Rosanna C. Barnard ◽  
Christopher I. Jarvis ◽  
Adam J. Kucharski ◽  
...  
Keyword(s):  
United States ◽  
Severe Acute Respiratory Syndrome ◽  
Reproduction Number ◽  
The United States ◽  
Control Measures ◽  
Transmission Model ◽  
Educational Institutions ◽  
Stringent Control ◽  
Dynamic Transmission Model ◽  
Credible Intervals

A severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant, VOC 202012/01 (lineage B.1.1.7), emerged in southeast England in September 2020 and is rapidly spreading toward fixation. Using a variety of statistical and dynamic modeling approaches, we estimate that this variant has a 43 to 90% (range of 95% credible intervals, 38 to 130%) higher reproduction number than preexisting variants. A fitted two-strain dynamic transmission model shows that VOC 202012/01 will lead to large resurgences of COVID-19 cases. Without stringent control measures, including limited closure of educational institutions and a greatly accelerated vaccine rollout, COVID-19 hospitalizations and deaths across England in the first 6 months of 2021 were projected to exceed those in 2020. VOC 202012/01 has spread globally and exhibits a similar transmission increase (59 to 74%) in Denmark, Switzerland, and the United States.

Preliminary Estimates of Costs of Foodborne Disease in the United States

1989 ◽  
Vol 52 (8) ◽  
pp. 595-601 ◽  
Author(s):  
EWEN C. D. TODD
Keyword(s):  
United States ◽  
Food Industry ◽  
The United States ◽  
Control Measures ◽  
Effective Control ◽  
Foodborne Diseases ◽  
Hemorrhagic Colitis ◽  
E Coli ◽  
The Cost ◽  
Total Impact

Although the full economic impact of foodborne diseases has yet to be measured, preliminary studies show that the cost of illness, death, and business lost is high indeed. This impact is probably greatest in developing countries, but few facts are known. For the United States, preliminary estimates are 12.6 million cases costing $8.4 billion. These may seem excessive but other authors have postulated even higher case and dollar figures. Microbiological diseases (bacterial and viral) represent 84% of the United States' costs, with salmonellosis and staphylococcal intoxication being the most economically important diseases (annually $4.0 billion and $1.5 billion, respectively). Other costly types of illnesses are toxoplasmosis ($445 million), listeriosis ($313 million), campylobacteriosis ($156 million), trichinosis ($144 million), Clostridium perfringens enteritis ($123 million), and E. coli infections including hemorrhagic colitis ($223 million). Botulism has a high cost per case ($322,200), but its total impact is only $87 million because relatively few cases occur (270). This is because the food industry has been able to introduce effective control measures. Salmonellosis, however, is much more widespread (2.9 million cases) and affects all sectors of the food industry.

scholarly journals Similarities and Differences in COVID-19 Awareness, Concern, and Symptoms by Race and Ethnicity in the United States: Cross-Sectional Survey (Preprint)

2020 ◽  
Author(s):  
Jeb Jones ◽  
Patrick S Sullivan ◽  
Travis H Sanchez ◽  
Jodie L Guest ◽  
Eric W Hall ◽  
...  
Keyword(s):  
United States ◽  
Race And Ethnicity ◽  
Online Survey ◽  
Statistical Tests ◽  
The United States ◽  
Control Measures ◽  
Cross Sectional Survey ◽  
Cross Sectional ◽  
Similarities And Differences ◽  
Hispanic White

BACKGROUND Existing health disparities based on race and ethnicity in the United States are contributing to disparities in morbidity and mortality during the coronavirus disease (COVID-19) pandemic. We conducted an online survey of American adults to assess similarities and differences by race and ethnicity with respect to COVID-19 symptoms, estimates of the extent of the pandemic, knowledge of control measures, and stigma. OBJECTIVE The aim of this study was to describe similarities and differences in COVID-19 symptoms, knowledge, and beliefs by race and ethnicity among adults in the United States. METHODS We conducted a cross-sectional survey from March 27, 2020 through April 1, 2020. Participants were recruited on social media platforms and completed the survey on a secure web-based survey platform. We used chi-square tests to compare characteristics related to COVID-19 by race and ethnicity. Statistical tests were corrected using the Holm Bonferroni correction to account for multiple comparisons. RESULTS A total of 1435 participants completed the survey; 52 (3.6%) were Asian, 158 (11.0%) were non-Hispanic Black, 548 (38.2%) were Hispanic, 587 (40.9%) were non-Hispanic White, and 90 (6.3%) identified as other or multiple races. Only one symptom (sore throat) was found to be different based on race and ethnicity (<i>P</i>=.003); this symptom was less frequently reported by Asian (3/52, 5.8%), non-Hispanic Black (9/158, 5.7%), and other/multiple race (8/90, 8.9%) participants compared to those who were Hispanic (99/548, 18.1%) or non-Hispanic White (95/587, 16.2%). Non-Hispanic White and Asian participants were more likely to estimate that the number of current cases was at least 100,000 (<i>P</i>=.004) and were more likely to answer all 14 COVID-19 knowledge scale questions correctly (Asian participants, 13/52, 25.0%; non-Hispanic White participants, 180/587, 30.7%) compared to Hispanic (108/548, 19.7%) and non-Hispanic Black (25/158, 15.8%) participants. CONCLUSIONS We observed differences with respect to knowledge of appropriate methods to prevent infection by the novel coronavirus that causes COVID-19. Deficits in knowledge of proper control methods may further exacerbate existing race/ethnicity disparities. Additional research is needed to identify trusted sources of information in Hispanic and non-Hispanic Black communities and create effective messaging to disseminate correct COVID-19 prevention and treatment information.

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