Characterization of Podosphaera macularis Derived from the Hop Cultivar ‘Strata’ and Strata’s Resistance to Powdery Mildew in Oregon

2021 ◽  
Author(s):  
Mary Block ◽  
Michele S. Wiseman ◽  
David H. Gent
Keyword(s):  
Powdery Mildew ◽  
Disease Risk ◽  
Severe Disease ◽  
Patent Application ◽  
State University ◽  
Single Chain ◽  
Differential Cultivars ◽  
Oregon State University ◽  
Podosphaera Macularis

Powdery mildew is one of the most destructive diseases of hop. Host resistance is a most efficient means of managing the disease, but resistance may not be durable. The cultivar Strata was developed by Oregon State University, and the patent application stated the plant was resistant to powdery mildew based on initial greenhouse screening and 8 years of observations at three locations in western Oregon. In 2019, powdery mildew colonies were reported in a commercial yard of Strata near Woodburn, Oregon. Two clonal isolates of Podosphaera macularis were isolated via single-chain transfers from colonies and characterized by inoculating each of seven differential cultivars. Cultivars with Rb, R3, and R5 were susceptible to the isolates. The susceptibility of Strata to powdery mildew was characterized by inoculating seven isolates of P. macularis with known virulences onto leaves of Strata. Sporulation appeared on Strata leaves with all of the differential isolates independent of their specific virulence, but only at trace levels with isolates possessing V6-virulence. Strata-derived isolates were phenotypically indistinguishable from Cascade-adapted isolates when inoculated onto the cultivars Cascade, Strata, and Symphony, as only Strata-derived and Cascade-adapted isolates could cause severe disease on Cascade and Strata. Like Cascade-adapted isolates, Strata-derived isolates also lack virulence on hop plants possessing the R-gene R6. These findings should inform both disease risk assessment in the field and future breeding tactics and strategies involving Strata. Further characterization of Strata is warranted to determine if its resistance is under the same genetic control as Cascade.

scholarly journals Distribution and Characterization of Podosphaera macularis Virulent on Hop Cultivars Possessing R6-Based Resistance to Powdery Mildew

Plant Disease ◽  
2016 ◽  
Vol 100 (6) ◽  
pp. 1212-1221 ◽  
Author(s):  
Sierra N. Wolfenbarger ◽  
Stephen T. Massie ◽  
Cynthia Ocamb ◽  
Emily B. Eck ◽  
Gary G. Grove ◽  
...  
Keyword(s):  
United States ◽  
Powdery Mildew ◽  
Mating Type ◽  
Resistance Genes ◽  
Severe Disease ◽  
The United States ◽  
Fitness Cost ◽  
Eastern United States ◽  
Host Genotype ◽  
Podosphaera Macularis

Host resistance, both quantitative and qualitative, is the preferred long-term approach for disease management in many pathosystems, including powdery mildew of hop (Podosphaera macularis). In 2012, an epidemic of powdery mildew occurred in Washington and Idaho on previously resistant cultivars whose resistance was putatively based on the gene designated R6. In 2013, isolates capable of causing severe disease on cultivars with R6-based resistance were confirmed in Oregon and became widespread during 2014. Surveys of commercial hop yards during 2012 to 2014 documented that powdery mildew is now widespread on cultivars possessing R6 resistance in Washington and Oregon, and the incidence of disease is progressively increasing. Pathogenic fitness, race, and mating type of R6-virulent isolates were compared with isolates of P. macularis lacking R6 virulence. All isolates were positive for the mating type idiomorph MAT1-1 and were able to overcome resistance genes Rb, R3, and R5 but not R1 or R2. In addition, R6-virulent isolates were shown to infect differential cultivars reported to possess the R6 gene and also the R4 gene, although R4 has not yet been broadly deployed in the United States. R6-virulent isolates were not detected from the eastern United States during 2012 to 2015. In growth chamber studies, R6-virulent isolates of P. macularis had a significantly longer latent period and produced fewer lesions on plants with R6 as compared with plants lacking R6, indicating a fitness cost to the fungus. R6-virulent isolates also produced fewer conidia when compared with isolates lacking R6 virulence, independent of whether the isolates were grown on a plant with or without R6. Thus, it is possible that the fitness cost of R6 virulence occurs regardless of host genotype. In field studies, powdery mildew was suppressed by at least 50% on plants possessing R6 as compared with those without R6 when coinoculated with R6-virulent and avirulent isolates. R6 virulence in P. macularis appears to be race specific and, at this time, imposes a measurable fitness penalty on the fungus. Resistance genes R1 and R2 appear to remain effective against R6-virulent isolates of P. macularis in the U.S. Pacific Northwest.

Characterization of lncRNAs and mRNAs involved in powdery mildew resistance in cucumber

2021 ◽  
Author(s):  
Jingtao Nie ◽  
Huazen Wang ◽  
Wanlu Zhang ◽  
Xue Teng ◽  
Chao Yu ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Powdery Mildew Resistance ◽  
Severe Disease ◽  
Mature Mirnas ◽  
Marker Assisted Breeding ◽  
Resistant Varieties ◽  
Mirna Sequencing ◽  
Phenylpropanoid Biosynthesis ◽  
Phenylalanine Metabolism

Powdery mildew (PM) is a severe fungal disease of cucumber worldwide. Identification of genetic factors resistant to PM is of great importance for marker-assisted breeding to ensure cucumber production. Long noncoding RNAs (lncRNAs) and miRNAs have been shown to play important roles in plant development and immunity; however, whether they have a role in PM response in cucurbit crops remains unknown. Here, we performed strand-specific RNA sequencing and miRNA sequencing using RNA from cucumber leaves of two near-isogenic lines (NILs) S1003 and NIL (Pm5.1) infected with PM, and systematically characterized the profiles of cucumber lncRNAs and mRNAs responsive to PM. In total, we identified 12903 lncRNAs and 25598 mRNAs responsive to powdery mildew. Differential expression (DE) analysis showed that 119 lncRNAs and 136 mRNAs correlated with PM resistance. Functional analysis of these DE lncRNAs and DE mRNAs revealed that they are significantly associated with phenylpropanoid biosynthesis, phenylalanine metabolism, ubiquinone and other terpenoid-quinone biosynthesis, and endocytosis. Particularly, two lncRNAs, LNC_006805 and LNC_012667, might play important roles in PM resistance. In addition, we also predicted mature miRNAs and ceRNA(competing endogenouse RNA) networks of lncRNA–miRNA–mRNA involved in PM resistance. A total of 49 DE lncRNAs could potentially act as target mimics for 106 miRNAs. Taken together, our results provide an abundant resource for further exploration of cucumber lncRNAs, mRNAs, miRNAs, and ceRNAs in PM resistance, and will facilitate the molecular breeding for PM resistant varieties to control this severe disease in cucumber.

Temperature Influences on Powdery Mildew Susceptibility and Development in the Hop Cultivar Cascade

Plant Disease ◽  
2022 ◽  
Author(s):  
David H. Gent ◽  
Briana Claassen ◽  
Michele S. Wiseman ◽  
Sierra N Wolfenbarger
Keyword(s):  
Powdery Mildew ◽  
Partial Resistance ◽  
Disease Risk ◽  
Rapid Onset ◽  
Risk Assessments ◽  
Temperature Regimes ◽  
Moderate Disease ◽  
Ontogenic Resistance ◽  
Specific Temperature ◽  
Podosphaera Macularis

The hop cultivar Cascade possesses partial resistance to powdery mildew (Podosphaera macularis) that can be overcome by recently emerged, virulent isolates of the fungus. Given that hop is a long-lived perennial and that brewers still demand Cascade, there is a need to better understand factors that influence the development of powdery mildew on this cultivar. Growth chamber experiments were conducted to quantify the effect of constant, transient, and fluctuating temperature on Cascade before, concurrent to, and after inoculation as contrasted with another powdery mildew susceptible cultivar, Symphony. Exposure of plants to supraoptimal temperature (26 and 32°C) prior to inoculation led to more rapid onset of ontogenic resistance in intermediately aged leaves in Cascade as compared to Symphony. Cascade was overall less susceptible to powdery mildew when exposed to constant temperature ranging from 18 to 32°C directly after inoculation. However, cultivar also interacted with temperature such that proportionately fewer and smaller colonies developed on Cascade than Symphony at supraoptimal yet permissive temperatures for disease. When plants were inoculated and then exposed to high temperature, colonies became progressively more tolerant to temperatures of 26 to 30°C with increasing time from inoculation to exposure, as moderated by cultivar, the specific temperature, and their interaction. Subjecting plants to simulated diurnal temperature regimes at the time of inoculation or 24 h later indicated Cascade and Symphony responded proportionately similar on days predicted to be marginally unfavorable or marginally favorable for powdery mildew, although Cascade was quantitatively less susceptible than Symphony. In sum, this research indicates that Cascade is overall less susceptible to powdery mildew than Symphony, and supraoptimal temperature before, concurrent to, or after infection may interact differentially to moderate disease risk in Cascade. Therefore, cultivar-specific risk assessments for powdery mildew appear warranted.

scholarly journals Characterization of the Microanatomy and Histopathology of Placentas From Aborted, Stillborn, and Normally Delivered Alpacas (Vicugna pacos) and Llamas (Lama glama)

2011 ◽  
Vol 49 (2) ◽  
pp. 313-321 ◽  
Author(s):  
D. L. Schaefer ◽  
R. J. Bildfell ◽  
P. Long ◽  
C. V. Löhr
Keyword(s):  
Placental Insufficiency ◽  
State University ◽  
Diagnostic Laboratory ◽  
Crown Rump Length ◽  
Routine Testing ◽  
Vicugna Pacos ◽  
Microscopic Features ◽  
Lama Glama ◽  
Oregon State University

From 2002 to 2007, 101 camelid abortions and stillbirths were submitted to the Veterinary Diagnostic Laboratory at Oregon State University (84 alpacas [ Vicugna pacos], 13 llamas [ Lama glama], 4 unknown). For most cases ( n = 67), a cause was not determined by routine testing. Eighty-five submissions included placenta for microscopic examination, of which 55 were from abortions to unknown causes (idiopathic). Microscopic features of placentas from abortion/stillbirth were compared with those from 19 camelids delivered normally (6 alpacas, 12 llamas, 1 unknown) and with those from 4 alpaca fetuses of known gestational age collected during the dam’s necropsy. The most common microscopic findings in abortion/stillbirth placentas were mineralization ( n = 57) and mucinous edema ( n = 27) of the chorioallantoic stroma. One or more of these features were also observed in 22 of 23 placentas from normal pregnancies/deliveries and therefore interpreted as incidental findings. The comparison of alpaca placentas after matching for gestational parameters (crown–rump length, weight, days of gestation; n = 41) revealed hypoplasia of placental villi in 5 of 22 idiopathic abortions and in 1 abortion due to umbilical torsion; hypoplasia was further suspected in an additional 6 abortions of unknown cause and 2 abortions of known cause. The identified villous hypoplasia is assumed to have resulted in placental insufficiency. When placental insufficiency is included as cause, idiopathic abortions are reduced from 66.2 to 47.9% of alpaca cases with histopathologic examination of placenta and from 66.3 to 52.5% of alpaca and llama abortions overall. This study also permitted the generation of a linear regression curve correlating alpaca fetal crown–rump length with fetal age.

Characterization of Resistance to Powdery Mildew in the Hop Cultivars Newport and Comet

2014 ◽  
Vol 15 (2) ◽  
pp. 55-56 ◽  
Author(s):  
Sierra N. Wolfenbarger ◽  
Emily B. Eck ◽  
David H. Gent
Keyword(s):  
Powdery Mildew ◽  
Pacific Northwest ◽  
Host Resistance ◽  
Resistant Cultivars ◽  
Virulent Strains ◽  
The Pacific ◽  
Potential Sources ◽  
Important Disease ◽  
Podosphaera Macularis

Hop powdery mildew, caused by Podosphaera macularis, is an important disease in the Pacific Northwest. Resistant cultivars of hop have been developed and have provided field immunity to the disease until virulent strains of P. macularis emerged. Due to the increase of powdery mildew on formerly resistant cultivars, studies were conducted to characterize potential sources of host resistance. Accepted for publication 5 February 2014. Published 27 March 2014.

A comprehensive characterization of ecological and epidemiological factors driving perennation of Podosphaera macularis chasmothecia on hop (Humulus lupulus)

2021 ◽  
Author(s):  
William A Weldon ◽  
Michelle Marks ◽  
Amanda J Gevens ◽  
Kimberly Nicole D'Arcangelo ◽  
Lina Quesada-Ocampo ◽  
...  
Keyword(s):  
Disease Management ◽  
Powdery Mildew ◽  
Reproductive Strategies ◽  
Management Practices ◽  
Epidemiological Models ◽  
Early Season ◽  
Rain Events ◽  
Comprehensive Characterization ◽  
Podosphaera Macularis

Hop powdery mildew, caused by the ascomycete fungus Podosphaera macularis is a consistent threat to sustainable hop production. The pathogen utilizes two reproductive strategies for overwintering and perennation: (i) asexual vegetative hyphae on dormant buds that emerge the following season as infected shoots; and (ii) sexual ascocarps (chasmothecia), which are presumed to discharge ascospores during spring rain events. We demonstrate that P. macularis chasmothecia, in the absence of any asexual P. macularis growth forms, are a viable overwintering source capable of causing early season infection two to three orders of magnitude greater than that reported for perennation via asexual growth. Two epidemiological models were defined that describe (i) temperature-driven maturation of P. macularis chasmothecia; and (ii) ascosporic discharge in response to the duration of leaf wetness and prevailing temperatures. Podosphaera macularis ascospores were confirmed to be infectious at temperatures ranging from 5 to 20°C. The organism’s chasmothecia were also found to adhere tightly to the host tissue on which they formed, suggesting that these structures likely overwinter wherever hop tissue senesces within a hop yard. These observations suggest that existing early season disease management practices are especially crucial to controlling hop powdery mildew in the presence of P. macularis chasmothecia. Furthermore, these insights provide a baseline for the validation of weather driven models describing maturation and release of P. macularis ascospores that can eventually be incorporated into hop disease management programs.

scholarly journals Population Diversity and Structure of Podosphaera macularis in the Pacific Northwestern United States and Other Populations

2020 ◽  
Vol 110 (5) ◽  
pp. 1105-1116
Author(s):  
David H. Gent ◽  
Briana J. Claassen ◽  
David M. Gadoury ◽  
Niklaus J. Grünwald ◽  
Brian J. Knaus ◽  
...  
Keyword(s):  
United States ◽  
Powdery Mildew ◽  
Population Diversity ◽  
Western United States ◽  
Wild Plants ◽  
Eastern United States ◽  
The Pacific ◽  
Differential Cultivars ◽  
Pathogen Populations ◽  
Podosphaera Macularis

Powdery mildew, caused by Podosphaera macularis, is one of the most important diseases of hop. The disease was first reported in the Pacific Northwestern United States, the primary hop-growing region in this country, in the mid-1990s. More recently, the disease has reemerged in newly planted hopyards of the eastern United States, as hop production has expanded to meet demands of local craft brewers. The spread of strains virulent on previously resistant cultivars, the paucity of available fungicides, and the potential introduction of the MAT1-2 mating type to the western United States, all threaten sustainability of hop production. We sequenced the transcriptome of 104 isolates of P. macularis collected throughout the western United States, eastern United States, and Europe to quantify genetic diversity of pathogen populations and elucidate the possible origins of pathogen populations in the western United States. Discriminant analysis of principal components grouped isolates within three to five geographic populations, dependent on stringency of grouping criteria. Isolates from the western United States were phenotyped and categorized into one of three pathogenic races based on disease symptoms generated on differential cultivars. Western U.S. populations were clonal, irrespective of pathogenic race, and grouped with isolates originating from Europe. Isolates originating from wild hop plants in the eastern United States were genetically differentiated from all other populations, whereas isolates from cultivated hop plants in the eastern United States mostly grouped with isolates originating from the west, consistent with origins from nursery sources. Mating types of isolates originating from cultivated western and eastern U.S. hop plants were entirely MAT1-1. In contrast, a 1:1 ratio of MAT1-1 and MAT1-2 was observed with isolates sampled from wild plants or Europe. Within the western United States a set of highly differentiated loci were identified in P. macularis isolates associated with virulence to the powdery mildew R-gene R6. The weight of genetic and phenotypic evidence suggests a European origin of the P. macularis populations in the western United States, followed by spread of the pathogen from the western United States to re-emergent production regions in the eastern United States. Furthermore, R6 compatibility appears to have been selected from an extant isolate within the western United States. Greater emphasis on sanitation measures during propagation and quarantine policies should be considered to limit further spread of novel genotypes of the pathogen, both between and within production areas.

Rapid Isolation of High Molecular Weight Urokinase from Native Human Urine

1982 ◽  
Vol 47 (03) ◽  
pp. 197-202 ◽  
Author(s):  
Kurt Huber ◽  
Johannes Kirchheimer ◽  
Bernd R Binder
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Human Urine ◽  
Gel Filtration ◽  
Chain Structure ◽  
The Other ◽  
Single Chain ◽  
Apparent Homogeneity ◽  
Sequential Adsorption

SummaryUrokinase (UK) could be purified to apparent homogeneity starting from crude urine by sequential adsorption and elution of the enzyme to gelatine-Sepharose and agmatine-Sepharose followed by gel filtration on Sephadex G-150. The purified product exhibited characteristics of the high molecular weight urokinase (HMW-UK) but did contain two distinct entities, one of which exhibited a two chain structure as reported for the HMW-UK while the other one exhibited an apparent single chain structure. The purification described is rapid and simple and results in an enzyme with probably no major alterations. Yields are high enough to obtain purified enzymes for characterization of UK from individual donors.

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