scholarly journals First Report of Root-Knot Nematode Meloidogyne enterolobii on Poinsettia ‘Luv U Pink’ in Taiwan

Plant Disease ◽  
2021 ◽  
Author(s):  
Che-Chang Liang ◽  
P. Janet Chen
Keyword(s):  
United States ◽  
18S Rrna ◽  
The United States ◽  
18S Rrna Gene ◽  
Rrna Gene ◽  
First Report ◽  
Meloidogyne Enterolobii ◽  
Mock Control ◽  
Haplotype 1 ◽  
Coii Region

Poinsettia (Euphorbia pulcherrima Willd. ex Klotzsch.), originated in southern Mexico and northern Guatemala, is the most valuable potted flowering plant in the spurge family (Euphorbiaceae). The European Union and the United States are two biggest poinsettia markets (Taylor et al. 2011), with a wholesale value of $153 million in the United States in 2019. Root knot galls of poinsettia ‘Luv U Pink’ were collected from a production greenhouse located in Nantou County, Taiwan in March 2021. No aboveground symptoms were observed. A nematode population was established from a single female and used for identification and the Koch’s postulate. The perineal patterns of randomly picked 5 females are round or ovoid with moderate to high dorsal arches, but no distinct lateral lines, ventral striae are fine and smooth. The Morphometric characters of second-stage juvenile include: a vermiform body shape, tail narrow and tapering with rounded tail tips, and a distinct hyaline tail end. Measurements of 20 J2 are as follows: body length, 430 (398 - 473) μm; body width, 15.4 (13.4 - 17.8) μm; stylet length,13.4 (13.0 - 14.0) μm; dorsal esophageal gland orifice to basal knob, 3.4 (2.8 - 3.9) μm; tail length, 52.9 (47.6 - 62.2) μm. All morphometric data were consistent with the original description of Meloidogyne enterolobii (Yang and Eisenback 1983). Nematode DNA was extracted using GeneMark Tissue & Cell Genomic DNA Purification Kit (GeneMark, Taiwan) from approximately 1500 J2 and used for amplification of 18S rRNA gene, a D2-D3 region of 28S rRNA gene, and a mtDNA COII region with primer sets 1A/MelR, D2A/D3B, and C2F3/1108, respectively (Power and Harris 1993, Subbotin et al. 2006, Tigano et al. 2005). The sequence of 18S rRNA gene (accession no. MZ948800 haplotype 1 and MZ955998 haplotype 2), haplotype 1 shared 100% identity with that of M. enterolobii from the United States (KP901058) and China (MN832688); haplotype 2 shared 99.8% identity with that of KP901058 and MN832688. The sequence of the D2-D3 region (MZ955995) shared 99% identity with that M. enterolobii from the United States (KP901079). Sequence of the COII region (MZ964625) also shared 99% identity with that of M. enterolobii from the United States (AY446975) and China (MN840970). Phylogenetic trees of the three gene sequences plotted as described by Ye et al. (2021) revealed that the newly described nematode was grouped with M. enterolobii. Sequence analysis of two fragments: 236 bp and 520 bp amplified with gene specific primers Me-F/R and MK7F/R, respectively (Long et al. 2006, Tigano et al. 2010) also confirmed the identity of M. enterolobii. To measure the reproductive factor (Rf), the Poinsettia ‘Luv U Pink’ seedlings with eight true leaves were transplanted into three 12-cm diameter pots each containing 6000 eggs or water (mock control). Forty-five days after inoculation, the average Rf value of three inoculated plants was 6, and no galls were observed on mock control plant roots, confirming that poinsettia is the host of M. enterolobii. M. enterolobii has been reported in several Euphorbia species, including E. heterophylla, E. prostrata, E. punicea and E. tirucalli (Han et al. 2012, Rich et al. 2009). To the best of our knowledge, this is the first report of M. enterolobii infecting E. pulcherrima ‘Luv U Pink’. 

scholarly journals First Report of Root-Knot Nematode Meloidogyne enterolobii on Cockscomb (Celosia argentea var. cristata) in Taiwan

Plant Disease ◽  
2021 ◽  
Author(s):  
Jo Tzu Ho ◽  
Che-Chang Liang ◽  
P. Janet Chen
Keyword(s):  
United States ◽  
18S Rdna ◽  
The United States ◽  
Root Knot Nematode ◽  
First Report ◽  
Meloidogyne Enterolobii ◽  
Celosia Argentea ◽  
Pathogenicity Tests ◽  
Primer Sets ◽  
Coii Region

Cockscomb (Celosia argentea) is commonly found in subtropical and temperate zones of Africa, South America and South East Asia, and is a popular ornamental plant in the family Amaranthaceae. Cockscomb has been known to contain antiviral proteins, betalains, and anthocyanin, which can be applied in beneficial ways (2). In September 2020, a cockscomb plant (Celosia argentea var. cristata) showing typical galling root symptoms likely infected by root-knot nematodes (Meloidogyne sp.) was collected from a garden in Taichung, Taiwan, and a quick exam of several individuals using MK7F/R primers (7) indicating they were M. enterolobii. Nematode population was established from a single egg mass and was later used for species identification and pathogenicity tests. Five perineal patterns of mature females from the single female population show round to oval shapes with weak lateral lines. Dorsal arches are moderate to high, almost squared, with the smooth ventral striae. Second-stage juveniles are vermiform and have a slender tail, tapering to rounded tip with distinct hyaline region at the tail terminus. Morphological measurements of 28 J2s revealed body length = 457.2 ± 20.6 (416.1-506.9) μm, body width = 16.0 ± 2.0 (13.4-20.3) μm, stylet length = 14.7 ± 0.5 (13.9-15.9) μm, dorsal gland orifice to the stylet base = 4.0 ± 0.5 (2.0-4.8) μm, and tail length = 56.0 ± 3.8 (47.4-60.3) μm. Female perineal patterns and morphometric data are similar to the original description of Meloidogyne enterolobii (9). DNA purified from approximately 1500 juveniles using GeneMark Tissue & Cell Genomic DNA Purification Kit (GeneMark, Taiwan) was used to amplify 18S rDNA fragment, D2-D3 expansion segments of 28S rDNA, and a COII region on mtDNA with primer sets 1A/MelR, D2A/D3B, and C2F3/1108, respectively (4,5,6). The 18S rDNA sequence (OK076893) of this study shares 99.94% nucleotide identity with those of M. enterolobii isolated from the United States (KP901058) and China (MN832688). D2D3 sequence of haplotype 1 (OK076898) shows 100% identity to those of M. enterolobii from China (MT193450) and Taiwan (KP411230). Sequence of haplotype 2 (OK076899) shows 99.86% identity to those of M. enterolobii from the United States (MN809527) and China (MN269945). Sequence of the COII region (OK086042) show 99.86% identity to that of M. enterolobii from China (MN269945). Phylogenetic trees of the three gene sequences were plotted following Ye et al.(10), revealing that the newly described root-knot nematode on Cockscomb is grouped with other M. enterolobii isolates. DNA fragment amplified by primer sets Me-F/R(3) and MK7F/R specifically targeting of M. enterolobii yielded 236 bp and 520 bp, respectively. Pathogenicity tests were assayed, from July to September 2021, on three-week-old nematode-free cockscomb plant directly germinated from seeds of SkyStar® (ASUSA SPIKE SEEDS, Taipei, Taiwan) planted in a 10.5 cm diameter pot filled with 600 ml sterilized peat moss: sand (1:1, v/v) soil in a 28℃walk-in chamber. Nematode eggs were extracted using 0.05% NaoCl as described by Vrain(8), and cockscomb plants (n=3) were inoculated by adding 6000 eggs (10 eggs/ cm3). Cockscomb plants treated with water were used as mock controls. Rf value of the inoculated plants were determined by the method of Belair and Benoit (1) 45 days after inoculation, and the average was 4.13. No galls were observed on the roots of control plants. The results confirmed that cockscomb is the new host of M. enterolobii. To the best of our knowledge, this is the first report of M. enterolobii on Celosia argentea var. cristata in Taiwan.

scholarly journals Prevalence of infection and 18S rRNA gene sequences of Cytauxzoon species in Iberian lynx (Lynx pardinus) in Spain

Parasitology ◽  
2007 ◽  
Vol 134 (7) ◽  
pp. 995-1001 ◽  
Author(s):  
J. MILLÁN ◽  
V. NARANJO ◽  
A. RODRÍGUEZ ◽  
J. M. PÉREZ DE LA LASTRA ◽  
A. J. MANGOLD ◽  
...  
Keyword(s):  
18S Rrna ◽  
The United States ◽  
18S Rrna Gene ◽  
Conservation Strategies ◽  
Rrna Gene ◽  
Lynx Lynx ◽  
Iberian Lynx ◽  
Lynx Pardinus ◽  
Sierra Morena ◽  
Wild Felids

SUMMARYThe Iberian lynx (Lynx pardinus) is the most endangered felid in the world. Only about 160 individuals remain in 2 separate metapopulations in Southern Spain (Sierra Morena and Doñana). We obtained blood samples of 20 lynxes captured from 2004 to 2006, and determined the prevalence of infection and genetic diversity of Cytauxzoon spp. using 18S rRNA PCR and sequence analysis. Prevalence of infection was 15% (3 of 20). Cytauxzoon sp. was only detected in Sierra Morena. For phylogenetic analysis, we used the sequences reported in the present study and those characterized in different domestic and wild felids and ticks from North and South America, Asia and Europe. Three different Cytauxzoon sp. sequences were obtained. They were closely related to that obtained from a Spanish cat, but diverged in up to 1·0% with respect to the only previously reported sequence from an Iberian lynx. Conversely, the latter sequence clustered together with C. manul sequences obtained from Pallas cats (Otocolobus manul) in Mongolia. Our analysis yields a separate cluster of C. felis sequences from cats, wild felids and ticks in the United States and Brazil. These results suggest that at least 2 different Cytauxzoon spp. may be present in Iberian lynx. The apparent absence in one of the areas, together with the possibility of fatal cytauxzoonosis in lynxes makes necessary disease risks to be taken into account in management conservation strategies, such as translocations and re-introductions.

scholarly journals First Report of Bacterial Spot of Tomato Caused by Xanthomonas gardneri in Pennsylvania

Plant Disease ◽  
2010 ◽  
Vol 94 (5) ◽  
pp. 638-638 ◽  
Author(s):  
S. H. Kim ◽  
T. N. Olson ◽  
N. D. Peffer ◽  
E. V. Nikolaeva ◽  
S. Park ◽  
...  
Keyword(s):  
United States ◽  
Type Strain ◽  
Tap Water ◽  
The United States ◽  
Nutrient Broth ◽  
Rrna Gene ◽  
Bacterial Spot ◽  
Tomato Plants ◽  
First Report ◽  
Leaf Spots

Recent investigation of bacteria isolated from samples submitted to the Plant Disease Diagnostic Laboratory, Pennsylvania Department of Agriculture indicated that in 1995, Xanthomonas gardneri (ex Sutic 1957) (2) caused a leaf spot on tomato plants (Lycopersicon esculentum Mill.). In 1995, we examined 185 tomato and 36 pepper samples (13 field, 2 garden center, 38 greenhouse, 4 residence, 16 field-grown transplant, and 148 greenhouse-grown transplant samples). A processing company representative collected samples showing symptoms of bacterial spot of tomato on a hybrid, whole pack processing tomato, from a 16-ha field in Northumberland County, PA exhibiting almost 50% crop infection. Symptoms consisted of circular- to irregularly shaped, dark brown spots, <5 mm in diameter, and frequently with chlorotic haloes on leaves and stems. The center of a spot may be raised and scabby. Several spots on a single leaflet may coalesce and a portion or the entire leaflet may turn yellow or die. These symptoms were indistinguishable from those of bacterial spot caused by X. euvesicatoria, X. vesicatoria, and X. perforans. Bacterial streaming from lesions was evident under dark-field microscopy. Aerobic, gram-negative, yellow-pigmented, mucoid bacteria were isolated from the leaf spots and purified and stored in nutrient broth with 10% glycerol at –80°C. The 16S rRNA gene from a strain (PDA80951-95) typical of the cultures from these samples was sequenced (GenBank Accession No. GU573763). A BlastN search of GenBank revealed 100% nucleotide identity with the type strain of X. gardneri (XCGA2; No. AF123093). This strain also exhibited repetitive sequence-based (rep)-PCR profiles (4) identical to profiles of X. gardneri type strain XCGA2 DNA and produced a ~425-bp PCR product with BSX primers, a genetic marker indicative of X. gardneri (1). The strain was not amylolytic or pectolytic (2) and failed to utilize maltose, gentiobiose, and melezitose (3). For pathogenicity tests, inoculum was grown in nutrient broth with shaking for 24 h at 28°C. Inoculum was centrifuged, resuspended in sterile tap water, and adjusted to 2.5 × 108 CFU/ml. Lower leaf surfaces of tomato (cvs. Bonnie Best and Walter) and pepper (cvs. California Wonder and Early Niagara) plants were gently rubbed with sterile cheesecloth that was moistened with the inoculum. Strain PDA80951-95 caused leaf spots, with chlorotic haloes and occasional coalescence on both tomato and pepper, within 2 weeks at 15 s of mist per 20 min at 20 to 35°C in a secured greenhouse chamber. X. gardneri was only reisolated from symptomatic plants and its identity was confirmed by rep-PCR and absence of amylolytic and pectolytic activities. Negative controls consisting of X. campestris pv. campestris and sterile tap water did not show symptoms. A known type strain of X. gardneri was not included as a positive control for pathogenicity studies because this species is not known to occur in the United States (2). To our knowledge, this is the first report of bacterial spot on tomato plants caused by X. gardneri in Pennsylvania and the United States. Since the first occurrence in 1995, bacterial spot caused by X. gardneri reoccurred in Pennsylvania tomato fields in 2001 and consecutively from 2003 to 2009. Reference: (1) D. A. Cuppels et al. Plant Dis. 90:451, 2006. (2) J. B. Jones et al. Syst. Appl. Microbiol. 27:755, 2004. (3) A. M. Quezado-Duval et al. Plant Dis. 88:15, 2004. (4) D. J. Versalovic et al. Methods Mol. Cell Biol. 5:25, 1994.

scholarly journals First Report of Black Leg of Hydroponic Basil in the United States Caused by Plectosporium tabacinum

Plant Disease ◽  
2010 ◽  
Vol 94 (4) ◽  
pp. 484-484 ◽  
Author(s):  
D. Egel ◽  
G. Ruhl ◽  
S. Hoke ◽  
M. B. Dicklow ◽  
R. Wick
Keyword(s):  
United States ◽  
The United States ◽  
Deionized Water ◽  
Rrna Gene ◽  
Diseased Plant ◽  
Poor Growth ◽  
First Report ◽  
Laboratory Bench ◽  
Black Leg ◽  
Stem Lesions

During August 2007 and again in January 2008, compact sweet basil (Ocimum basilicum ‘Genovese’) plants grown hydroponically in Indiana displayed dark, irregular, stem lesions extending 2 to 3 cm above the interface of the nutrient solution. These necrotic stem lesions (black leg), observed on 20 to 30% of the basil plants caused very weak, brittle stems so that they could not be marketed fresh. Although no wilting was noted, reduced plant height was observed. Similar symptoms of blackleg and poor growth have been reported from Italy on greenhouse-grown basil infected with Microdochium tabacinum (1,2). Diseased plant samples were sent to diagnostic clinics at Purdue University and the University of Massachusetts. Stem samples were surface sterilized and plated on potato dextrose agar (PDA) acidified with 1 ml of 85% lactic acid per liter as well as onto one-quarter-strength PDA. A fungus morphologically consistent with Plectosporium tabacinum (van Beyma) M.E. Palm, W. Gams, & H.I. Nirenberg (synonyms M. tabacinum (von Arx, 1984) and Fusarium tabacinum (Gams & Gerlagh, 1968) (3) was cultured from the basil stems and identified as P. tabacinum by R. Wick. Cultures sent to J. McKemy and J. Bischof (USDA/APHIS/PPQ) and W. Elmer (Connecticut Agricultural Experiment Station) also were identified as P. tabacinum. Amplification of the 323-bp internal transcribed spacer (ITS) region (ITS1, 5.8S rRNA gene, ITS2) and subsequent BLAST alignments of the resulting sequence indicated a 98% match for Plectosphaerella cucumerina (anamorph P. tabacinum) (GenBank Accession No. U17399; MIDI Inc., Newark, DE). Inoculations were performed on basil plants grown in peat-based soilless medium in a greenhouse for 6 weeks. Immediately before inoculation, the roots were washed with tap water to remove the peat-based medium. A single basil plant was placed in each of eight, 125-ml Erlenmeyer flasks. Four flasks were filled with 100 ml of deionized water as negative controls and four were filled with a 1 × 106 CFU/ml water suspension of P. tabacinum so that the liquid reached the crown of the basil plant. Basil plants in the Erlenmeyer flasks were incubated on a laboratory bench at 23°C. After 24 h, the solutions in all flasks were discarded and each flask and root system was rinsed three times with deionized water. The plants were then incubated in deionized water on the laboratory bench for four to five additional days. Within 4 days, dark brown-to-black stem lesions similar to those observed originally on basil plants in the hydroponic production greenhouse developed on the plants at the water interface and extended up the stem. Lesions extended a mean of 22 mm above the water level on inoculated plants. Control plants remained symptomless. P. tabacinum was recovered from symptomatic tissue of inoculated plants to complete Koch's postulates. The experiment was repeated several times with similar results. Further evidence of pathogenicity was obtained by stem inoculation of basil plants growing in a soilless medium. These data indicate that P. tabacinum was the causal agent of the symptoms observed on the hydroponic basil. To our knowledge, this is the first report of P. tabacinum causing ‘black leg’ and reduced growth on basil in the United States and the first report in the world of P. tabacinum on hydroponic basil. References: (1) A. Garibaldi et al. Plant Dis. 81:124.1997. (2) A. Matta. Riv. Patol. Veg. Ser. IV 14:119, 1978. (3) M. Palm et al. Mycologia. 87:397.1995.

scholarly journals Ixodes persulcatus Ticks as Vectors for the Babesia microti U.S. Lineage in Japan

2016 ◽  
Vol 82 (22) ◽  
pp. 6624-6632 ◽  
Author(s):  
Aya Zamoto-Niikura ◽  
Shigeru Morikawa ◽  
Ken-Ichi Hanaki ◽  
Patricia J. Holman ◽  
Chiaki Ishihara
Keyword(s):  
United States ◽  
18S Rrna ◽  
The United States ◽  
Babesia Microti ◽  
Rrna Gene ◽  
Ixodes Persulcatus ◽  
Principal Vector ◽  
Content Type ◽  
Human Babesiosis ◽  
The U.S

ABSTRACTThe U.S. lineage, one of the major clades in theBabesia microtigroup, is known as a causal agent of human babesiosis mostly in the northeastern and upper midwestern United States. This lineage, however, also is distributed throughout the temperate zone of Eurasia with several reported human cases, although convincing evidence of the identity of the specific vector(s) in this area is lacking. Here, the goal was to demonstrate the presence of infectious parasites directly in salivary glands ofIxodes persulcatus, from which U.S. lineage genetic sequences have been detected in Asia, and to molecularly characterize the isolates. Five PCR-positive specimens were individually inoculated into hamsters, resulting in infections in four; consequently, four strains were newly established. Molecular characterization, including 18S rRNA, β-tubulin, andCCT7gene sequences, as well as Western blot analysis and indirect fluorescent antibody assay, revealed that all four strains were identical to each other and to the U.S. lineage strains isolated from rodents captured in Japan. The 18S rRNA gene sequence from the isolates was identical to those fromI. persulcatusin Russia and China, but the genetic and antigenic profiles of the Japanese parasites differ from those in the United States and Europe. Together with previous epidemiological and transmission studies, we conclude thatI. persulcatusis likely the principal vector for theB. microtiU.S. lineage in Japan and presumably in northeastern Eurasia.IMPORTANCEThe major cause of human babesiosis, the tick-borne blood parasiteBabesia microti, U.S. lineage, is widely distributed in the temperate Northern Hemisphere. However, the specific tick vector(s) remains unidentified in Eurasia, where there are people with antibodies to theB. microtiU.S. lineage and cases of human babesiosis. In this study, the first isolation ofB. microtiU.S. lineage fromIxodes persulcatusticks, a principal vector for many tick-borne diseases, is described in Japan. Limited antigenic cross-reaction was found between the Japan and United States isolates. Thus, current serological tests based on U.S. isolates may underestimateB. microtioccurrence outside the United States. This study and previous studies indicate thatI. persulcatusis part of theB. microtiU.S. lineage life cycle in Japan and, presumably, northeastern Eurasia. This report will be important for public health, especially since infection may occur through transfusion, and also to researchers in the field of parasitology.

scholarly journals Phylogenetic Analysis of the Hypervariable Region of the 18S rRNA Gene of Cryptosporidium Oocysts in Feces of Canada Geese (Branta canadensis): Evidence for Five Novel Genotypes

2004 ◽  
Vol 70 (1) ◽  
pp. 452-458 ◽  
Author(s):  
Kristen L. Jellison ◽  
Daniel L. Distel ◽  
Harold F. Hemond ◽  
David B. Schauer
Keyword(s):  
Genetic Diversity ◽  
Phylogenetic Analysis ◽  
18S Rrna ◽  
Hypervariable Region ◽  
Pcr Amplification ◽  
The United States ◽  
18S Rrna Gene ◽  
Rrna Gene ◽  
Canada Geese ◽  
Pcr Products

ABSTRACT To assess genetic diversity in Cryptosporidium oocysts from Canada geese, 161 fecal samples from Canada geese in the United States were analyzed. Eleven (6.8%) were positive for Cryptosporidium spp. following nested PCR amplification of the hypervariable region of the 18S rRNA gene. Nine PCR products from geese were cloned and sequenced, and all nine diverged from previously reported Cryptosporidium 18S rRNA gene sequences. Five sequences were very similar or identical to each other but genetically distinct from that of Cryptosporidium baileyi; two were most closely related to, but genetically distinct from, the first five; and two were distinct from any other sequence analyzed. One additional sequence in the hypervariable region of the 18S rRNA gene isolated from a cormorant was identical to that of C. baileyi. Phylogenetic analysis provided evidence for new genotypes of Cryptosporidium species in Canada geese. Results of this study suggest that the taxonomy of Cryptosporidium species in geese is complex and that a more complete understanding of genetic diversity among these parasites will facilitate our understanding of oocyst sources and species in the environment.

scholarly journals First Report of Bacterial Leaf Streak of Strelitzia reginae Caused by Burkholderia cepacia

Plant Disease ◽  
2014 ◽  
Vol 98 (5) ◽  
pp. 682-682
Author(s):  
C. P. You ◽  
M. M. Xiang ◽  
Y. X. Zhang
Keyword(s):  
United States ◽  
Burkholderia Cepacia ◽  
Xanthomonas Campestris ◽  
The United States ◽  
Anaerobic Growth ◽  
Flowering Plant ◽  
Rrna Gene ◽  
Bacterial Leaf Streak ◽  
First Report ◽  
Strelitzia Reginae

In 2011, the bacterial leaf streak disease of the monocotyledonous flowering plant, commonly known as bird of paradise (Strelitzia reginae), occurred in a nursery in Guangzhou, Guangdong Province, China. Lesions on diseased leaves began as water-soaked leaf spots or streaks near the central and secondary veins, eventually expanded along veins and became brown necrotic streaks. Occasionally, during wet conditions, seedlings were completely blighted. The disease incidence was about 12% in the nursery. Bacteria were consistently isolated on nutrient agar (NA) (4) from surface-sterilized symptomatic lesions and purified on NA. Three bacterial strains were tested for pathogenicity on S. reginae plants. Three plants were inoculated per bacterial strain (bacterial suspensions 107 CFU/ml in nutrient broth [NB] [4]) by wounding three young, fully expanded leaves (four wounds per leaf) with needle. Plants were placed in polyethylene bags 1 day before inoculation and maintained for 7 days after inoculation. Three control plants were inoculated with NB. Water-soaked areas on leaves were observed on all inoculated plants 7 days after inoculation. Within 10 days, brown streaks were observed. All strains induced similar symptoms as those observed on the plants in the nursery. Control plants showed no symptoms. For molecular identification, a near full-length sequence of the 16S rRNA gene was amplified from strain TNT1-1 (GenBank Accession No. JX901049.1) with primers 27F and 1492R (3), obtaining a PCR product of ~1,500 bp. A BLAST search in GenBank revealed the highest similarity (99.5%) to sequences of Burkholderia cepacia (FN178432.1 and FN178432.1). BIOLOG identification showed that TTN1-1 had the highest probability index of 0.85 and highest similarity index of 0.85 to B. cepacia. For biochemical characteristics, the strain was gram negative, anaerobic growth test negative, oxidase negative, catalase positive, did not produce fluorescent pigment on KB (4), did not grow on DIM agar (4), arginine dihydrolysis negative, nitrate reduction negative, starch hydrolysis negative, gelatin liquefaction negative, citrate, D-arabinose, L-fructose, trehalose, and maltose utilization positive, didn't produce acid from glucose, and grew on Tween 80 medium at 41°C. The above characteristics were identical to that of reference isolate B. cepacia ATCC 25416. Additionally, bacteria isolated on NA from the leading edge of lesions of inoculated plants with the strain were identical to the inoculated strain based on 16S rDNA sequence analysis, but no bacteria were recovered from the wounded sites on the control plants. Therefore, bacterial leaf streak of bird of paradise is caused by B. cepacia based on Koch's postulates. In contrast, two bacterial diseases on S. reginae were previously reported to be caused by Xanthomonas campestris (1) and B. gladioli (2) in the United States and Italy, respectively. A similar leaf streak disease on S. nicolai was caused by Acidovorax avenae subsp. avenae in the United States (5). To our knowledge, this is the first report of a leaf streak disease on S. reginae caused by B. cepacia. References: (1) A. R. Chase and J. B. Jones. Plant Dis. 71:845, 1987. (2) G. Cirvilleri et al. Plant Dis. 90:1553, 2006. (3) I. M. Lee et al. Appl. Environ. Microbiol. 63:2631, 1997. (4) N. W. Schaad et al. Laboratory Guide for Identification of Plant Pathogenic Bacteria. 3rd ed. The American Phytopathological Society, St. Paul, MN, 2001. (5) T. E. Seijo and N. A. Peres. Plant Dis. 95:1474, 2011.

scholarly journals Analytical validation of a real-time hydrolysis probe PCR assay for quantifying Plasmodium falciparum parasites in experimentally infected human adults

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Claire Y. T. Wang ◽  
Emma L. Ballard ◽  
Zuleima Pava ◽  
Louise Marquart ◽  
Jane Gaydon ◽  
...  
Keyword(s):  
Clinical Trials ◽  
Plasmodium Falciparum ◽  
18S Rrna ◽  
Drug Efficacy ◽  
18S Rrna Gene ◽  
Molecular Techniques ◽  
Qpcr Assay ◽  
Rrna Gene ◽  
Analytical Sensitivity ◽  
Blood Samples

Abstract Background Volunteer infection studies have become a standard model for evaluating drug efficacy against Plasmodium infections. Molecular techniques such as qPCR are used in these studies due to their ability to provide robust and accurate estimates of parasitaemia at increased sensitivity compared to microscopy. The validity and reliability of assays need to be ensured when used to evaluate the efficacy of candidate drugs in clinical trials. Methods A previously described 18S rRNA gene qPCR assay for quantifying Plasmodium falciparum in blood samples was evaluated. Assay performance characteristics including analytical sensitivity, reportable range, precision, accuracy and specificity were assessed using experimental data and data compiled from phase 1 volunteer infection studies conducted between 2013 and 2019. Guidelines for validation of laboratory-developed molecular assays were followed. Results The reportable range was 1.50 to 6.50 log10 parasites/mL with a limit of detection of 2.045 log10 parasites/mL of whole blood based on a parasite diluted standard series over this range. The assay was highly reproducible with minimal intra-assay (SD = 0.456 quantification cycle (Cq) units [0.137 log10 parasites/mL] over 21 replicates) and inter-assay (SD = 0.604 Cq units [0.182 log10 parasites/mL] over 786 qPCR runs) variability. Through an external quality assurance program, the QIMR assay was shown to generate accurate results (quantitative bias + 0.019 log10 parasites/mL against nominal values). Specificity was 100% after assessing 164 parasite-free human blood samples. Conclusions The 18S rRNA gene qPCR assay is specific and highly reproducible and can provide reliable and accurate parasite quantification. The assay is considered fit for use in evaluating drug efficacy in malaria clinical trials.

First Report of Pathogenicity of Fusarium sporotrichioides and Fusarium acuminatum on Sunflowers in the United States

2010 ◽  
Vol 11 (1) ◽  
pp. 42 ◽  
Author(s):  
F. Mathew ◽  
B. Kirkeide ◽  
T. Gulya ◽  
S. Markell
Keyword(s):  
United States ◽  
Helianthus Annuus ◽  
The United States ◽  
Fusarium Sporotrichioides ◽  
Charcoal Rot ◽  
Koch’S Postulates ◽  
First Report ◽  
Fusarium Acuminatum ◽  
Helianthus Annuus L ◽  
Koch's Postulates

Widespread infection of charcoal rot was observed in a commercial sunflower field in Minnesota in September 2009. Based on morphology, isolates were identified as F. sporotrichioides and F. acuminatum. Koch's postulates demonstrated pathogencity of both species. To our knowledge, this is the first report of F. sporotrichoides and F. acuminatum causing disease on Helianthus annuus L. in the United States. Accepted for publication 23 August 2010. Published 15 September 2010.

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