Testing addition of Pseudomonas fluorescens HYK0210-SK09 to mitigate blooms of the diatom Stephanodiscus hantzschii in small- and large-scale mesocosms

2009 ◽  
Vol 22 (4) ◽  
pp. 409-419 ◽  
Author(s):  
Seung Won Jung ◽  
Yoon-Ho Kang ◽  
Toshiya Katano ◽  
Baik-Ho Kim ◽  
Soo-Yeon Cho ◽  
...  
Keyword(s):  
Pseudomonas Fluorescens ◽  
Large Scale ◽  
Stephanodiscus Hantzschii

scholarly journals A Bacterial Type III Secretion Assay for Delivery of Fungal Effector Proteins into Wheat

2014 ◽  
Vol 27 (3) ◽  
pp. 255-264 ◽  
Author(s):  
Narayana M. Upadhyaya ◽  
Rohit Mago ◽  
Brian J. Staskawicz ◽  
Michael A. Ayliffe ◽  
Jeffrey G. Ellis ◽  
...  
Keyword(s):  
Pseudomonas Fluorescens ◽  
Delivery System ◽  
Type Iii Secretion ◽  
Large Scale ◽  
Rust Fungus ◽  
Effector Proteins ◽  
In Planta ◽  
Host Genotype ◽  
Reporter Protein ◽  
Type Iii

Large numbers of candidate effectors from fungal pathogens are being identified through whole-genome sequencing and in planta expression studies. Although Agrobacterium-mediated transient expression has enabled high-throughput functional analysis of effectors in dicot plants, this assay is not effective in cereal leaves. Here, we show that a nonpathogenic Pseudomonas fluorescens engineered to express the type III secretion system (T3SS) of P. syringae and the wheat pathogen Xanthomonas translucens can deliver fusion proteins containing T3SS signals from P. syringae (AvrRpm1) and X. campestris (AvrBs2) avirulence (Avr) proteins, respectively, into wheat leaf cells. A calmodulin-dependent adenylate cyclase reporter protein was delivered effectively into wheat and barley by both bacteria. Absence of any disease symptoms with P. fluorescens makes it more suitable than X. translucens for detecting a hypersensitive response (HR) induced by an effector protein with avirulence activity. We further modified the delivery system by removal of the myristoylation site from the AvrRpm1 fusion to prevent its localization to the plasma membrane which could inhibit recognition of an Avr protein. Delivery of the flax rust AvrM protein by the modified delivery system into transgenic tobacco leaves expressing the corresponding M resistance protein induced a strong HR, indicating that the system is capable of delivering a functional rust Avr protein. In a preliminary screen of effectors from the stem rust fungus Puccinia graminis f. sp. tritici, we identified one effector that induced a host genotype-specific HR in wheat. Thus, the modified AvrRpm1:effector–Pseudomonas fluorescens system is an effective tool for large-scale screening of pathogen effectors for recognition in wheat.

scholarly journals Pseudomonas fluorescens Showing Antifungal Activity against Macrophomina phaseolina, a Severe Pathogenic Fungus of Soybean, Produces Phenazine as the Main Active Metabolite

Biomolecules ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1728
Author(s):  
Stefany Castaldi ◽  
Marco Masi ◽  
Francisco Sautua ◽  
Alessio Cimmino ◽  
Rachele Isticato ◽  
...  
Keyword(s):  
Antifungal Activity ◽  
Pseudomonas Fluorescens ◽  
Large Scale ◽  
Pathogenic Fungus ◽  
Macrophomina Phaseolina ◽  
Scale Production ◽  
Oh Groups ◽  
Large Scale Production ◽  
Sar Study

Pseudomonas fluorescens 9 and Bacillus subtilis 54, proposed as biofungicides to control Macrophomina phaseolina, a dangerous pathogen of soybean and other crops, were grown in vitro to evaluate their ability to produce metabolites with antifungal activity. The aim of the manuscript was to identify the natural compounds responsible for their antifungal activity. Only the culture filtrates of P. fluorescens 9 showed strong antifungal activity against M. phaseolina. Its organic extract contained phenazine and mesaconic acid (1 and 2), whose antifungal activity was tested against M. phaseolina, as well as Cercospora nicotianae and Colletotrichum truncatum, other pathogens of soybean; however, only compound 1 exhibited activity. The antifungal activity of compound 1 was compared to phenazine-1-carboxylic acid (PCA, 3), 2-hydroxyphenazine (2-OH P, 4), and various semisynthetic phenazine nitro derivatives in order to perform a structure–activity relationship (SAR) study. PCA and phenazine exhibited the same percentage of growth inhibition in M. phaseolina and C. truncatum, whereas PCA (3) showed lower activity against C. nicotianae than phenazine. 2-Hydroxyphenazine (4) showed no antifungal activity against M. phaseolina. The results of the SAR study showed that electron attractor (COOH and NO2) or repulsor (OH) groups significantly affect the antifungal growth, as well as their α- or β-location on the phenazine ring. Both PCA and phenazine could be proposed as biopesticides to control the soybean pathogens M. phaseolina, C. nicotianae, and C. truncatum, and these results should prompt an investigation of their large-scale production and their suitable formulation for greenhouse and field applications.

Some comments about observations and image processing of comet 29P/Schwassmann-Wachmann 1

1999 ◽  
Vol 173 ◽  
pp. 243-248
Author(s):  
D. Kubáček ◽  
A. Galád ◽  
A. Pravda
Keyword(s):  
Image Processing ◽  
Large Scale ◽  
Harvard College ◽  
Oak Ridge ◽  
Large Scale Structures ◽  
Short Period Comet ◽  
Short Period ◽  
Scale Structures ◽  
Harvard College Observatory ◽  
Period Comet

AbstractUnusual short-period comet 29P/Schwassmann-Wachmann 1 inspired many observers to explain its unpredictable outbursts. In this paper large scale structures and features from the inner part of the coma in time periods around outbursts are studied. CCD images were taken at Whipple Observatory, Mt. Hopkins, in 1989 and at Astronomical Observatory, Modra, from 1995 to 1998. Photographic plates of the comet were taken at Harvard College Observatory, Oak Ridge, from 1974 to 1982. The latter were digitized at first to apply the same techniques of image processing for optimizing the visibility of features in the coma during outbursts. Outbursts and coma structures show various shapes.

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