scholarly journals Infection of the Native California Grass, Bromus carinatus, by Fusarium circinatum, the Cause of Pitch Canker in Pines

Plant Disease ◽  
2020 ◽  
Vol 104 (1) ◽  
pp. 194-197
Author(s):  
Jason W. Carter ◽  
Thomas R. Gordon
Keyword(s):  
Fluorescent Protein ◽  
Leaf Tissue ◽  
Pitch Canker ◽  
Fusarium Circinatum ◽  
Holcus Lanatus ◽  
Native Grass ◽  
Point Reyes National Seashore ◽  
Bromus Carinatus ◽  
Point Reyes ◽  
Green Fluorescent

At Point Reyes National Seashore in California, Fusarium circinatum, the causal agent of pitch canker in pines, was isolated from Pinus muricata, the California native grass, Bromus carinatus, and the introduced grass, Holcus lanatus. All grass plants from which F. circinatum was isolated were symptomless. Pathogenicity of grass isolates was confirmed by inoculation of P. radiata trees, which developed symptoms similar to trees inoculated with a pine isolate of F. circinatum. Isolates from grasses were somatically compatible with isolates recovered from symptomatic pines. B. carinatus grown in a growth chamber was inoculated with a green fluorescent protein-expressing strain of F. circinatum. Segments of inoculated leaves were incubated in moist chambers; after 1 to 2 days, sporulating hyphae were observed growing from leaf tissue. Spores of F. circinatum removed from B. carinatus leaves were confirmed to be fluorescent when illuminated with ultraviolet light. These results raise the possibility that B. carinatus cryptically infected by F. circinatum may be a source of propagules capable of infecting pines.

scholarly journals Evidence for a Hemibiotrophic Association of the Pitch Canker Pathogen Fusarium circinatum with Pinus radiata

Plant Disease ◽  
2016 ◽  
Vol 100 (1) ◽  
pp. 79-84 ◽  
Author(s):  
Cassandra L. Swett ◽  
Sharon C. Kirkpatrick ◽  
Thomas R. Gordon
Keyword(s):  
Pinus Radiata ◽  
Fluorescent Protein ◽  
Pitch Canker ◽  
Fusarium Circinatum ◽  
Experimental Conditions ◽  
Root Cortex ◽  
Sequence Of Events ◽  
Pine Trees ◽  
History Of ◽  
Green Fluorescent

Fusarium circinatum can be a cause of mortality in pine seedlings but it is also possible for infected seedlings to remain symptomless. The results of this study documented a biotrophic phase in symptomless Pinus radiata seedlings that can persist for at least 52 weeks. A strain of F. circinatum, transformed to express the green fluorescent protein, was observed to grow intercellularly in the root cortex, with no evidence of damage to surrounding cells. Under experimental conditions, shoot symptoms developed only following collar infection, and root deterioration was seen only in plants that first expressed aboveground symptoms. This sequence of events implies that damage to the root system was a secondary consequence of girdling. If so, root symptoms may not reliably detect seedlings infected by F. circinatum. Supplemental mineral nutrition increased the incidence of infection and symptom development in seedlings but some infected plants remained symptomless, precluding the use of this approach to detect infected seedlings. Overall, our findings suggest that the ecological activities of F. circinatum may not be limited to a necrotrophic association with pine trees. A more comprehensive understanding of the life history of this fungus may yield insights that contribute to more effective management of pitch canker.

scholarly journals Colonization and movement of GFP-labeled Clavibacter nebraskensis in maize

Plant Disease ◽  
2020 ◽  
Author(s):  
Alexander Mullens ◽  
Tiffany Jamann
Keyword(s):  
Crop Residue ◽  
Fluorescent Protein ◽  
Control Method ◽  
Leaf Surface ◽  
Leaf Tissue ◽  
Primary Control ◽  
Bacterial Strains ◽  
Natural Conditions ◽  
Disease Symptoms ◽  
Green Fluorescent

Clavibacter nebraskensis (Cn) causes Goss’s bacterial wilt and leaf blight, a major disease of maize. Infected crop residue is the primary inoculum source and infection can occur via wounds or natural openings, such as stomata or hydathodes. The use of resistant hybrids is the primary control method for Goss’s wilt. In this study, colonization and movement patterns of Cn during infection were examined using green fluorescent protein (GFP)-labeled bacterial strains. We successfully introduced a plasmid to Cn via electroporation, which resulted in GFP accumulation. Fluorescence microscopy revealed that in the absence of wounding, bacteria colonize leaf tissue via entry through the hydathodes when guttation droplets are present. Stomatal penetration was not observed under natural conditions. Bacteria initially colonize the xylem and subsequently the mesophyll, which creates the freckles that are characteristic of the disease. Bacteria infiltrated into the mesophyll did not cause disease symptoms, could not enter the vasculature, and did not spread from the initial inoculation point. Bacteria were observed exuding through stomata onto the leaf surface, resulting in the characteristic sheen of diseased leaves. Resistant maize lines exhibited decreased bacterial spread in the vasculature and the mesophyll. These tools to examine Cn movement offer opportunities and new insights into the pathogenesis process and can form the basis for improved Goss’s wilt management through host resistance.

scholarly journals Cloning and Expression Analysis of the BocMBF1c Gene Involved in Heat Tolerance in Chinese Kale

2019 ◽  
Vol 20 (22) ◽  
pp. 5637 ◽  
Author(s):  
Lifang Zou ◽  
Bingwei Yu ◽  
Xing-Liang Ma ◽  
Bihao Cao ◽  
Guoju Chen ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Heat Stress ◽  
Green Fluorescent Protein ◽  
Stress Response ◽  
Nicotiana Benthamiana ◽  
Thermal Tolerance ◽  
Fluorescent Protein ◽  
Leaf Tissue ◽  
Chinese Kale ◽  
Green Fluorescent

Chinese kale (Brassica oleracea var. chinensis Lei) is an important vegetable crop in South China, valued for its nutritional content and taste. Nonetheless, the thermal tolerance of Chinese kale still needs improvement. Molecular characterization of Chinese kale’s heat stress response could provide a timely solution for developing a thermally tolerant Chinese kale variety. Here, we report the cloning of multi-protein bridging factor (MBF) 1c from Chinese kale (BocMBF1c), an ortholog to the key heat stress responsive gene MBF1c. Phylogenetic analysis showed that BocMBF1c is highly similar to the stress-response transcriptional coactivator MBF1c from Arabidopsis thaliana (AtMBF1c), and the BocMBF1c coding region conserves MBF1 and helix-turn-helix (HTH) domains. Moreover, the promoter region of BocMBF1c contains three heat shock elements (HSEs) and, thus, is highly responsive to heat treatment. This was verified in Nicotiana benthamiana leaf tissue using a green fluorescent protein (GFP) reporter. In addition, the expression of BocMBF1c can be induced by various abiotic stresses in Chinese kale which indicates the involvement of stress responses. The BocMBF1c-eGFP (enhanced green fluorescent protein) chimeric protein quickly translocated into the nucleus under high temperature treatment in Nicotiana benthamiana leaf tissue. Overexpression of BocMBF1c in Arabidopsis thaliana results in a larger size and enhanced thermal tolerance compared with the wild type. Our results provide valuable insight for the role of BocMBF1c during heat stress in Chinese kale.

scholarly journals Use of Green Fluorescent Protein-Transgenic Strains to Study Pathogenic and Nonpathogenic Lifestyles in Colletotrichum acutatum

2002 ◽  
Vol 92 (7) ◽  
pp. 743-749 ◽  
Author(s):  
Sigal Horowitz ◽  
Stanley Freeman ◽  
Amir Sharon
Keyword(s):  
Green Fluorescent Protein ◽  
Plant Species ◽  
Fluorescent Protein ◽  
Leaf Tissue ◽  
Colletotrichum Acutatum ◽  
Signal Molecules ◽  
Primary Host ◽  
Large Numbers ◽  
Cell Layers ◽  
Green Fluorescent

Colletotrichum acutatum, which causes anthracnose disease on strawberry, can also persist on several other plant species without causing disease symptoms. The genetic and molecular bases that determine pathogenic and nonpathogenic lifestyles in C. acutatum are unclear. We developed a transformation system for C. acutatum by electroporation of germinating conidia, and transgenic isolates that express the green fluorescent protein (GFP) were produced. Details of the pathogenic and nonpathogenic lifestyles of C. acutatum were determined by using GFP-transgenic isolates. Major differences between colonization-mediating processes of strawberry and of other plants were observed. On the main host, strawberry, the germinating conidia formed branched, thick hyphae, and large numbers of appressoria were produced that were essential for plant penetration. In strawberry, the fungus developed rapidly, filling the mesophyll with dense mycelium that invaded the cells and caused necrosis of the tissue. In nonpathogenic interactions on pepper, eggplant, and tomato, the conidia germinated, producing thin, straight germ tubes. Appressoria were produced but failed to germinate and penetrate leaf tissue, resulting in epiphytic growth without invasion of the plant. Penetration of the plant occurred only several days after inoculation and was restricted to the intercellular spaces of the first cell layers of infected tissue without causing any visible damage. Much of the new fungal biomass continued to develop on the surface of inoculated organs in the nonpathogenic interaction. The differences in fungal development on strawberry compared with the other plant species suggest that signal molecules, which may be present only in strawberry, trigger appressorial germination and penetration of the primary host.

A Unified Model for Photophysical and Electro-Optical Properties of Green Fluorescent Proteins

2019 ◽  
Author(s):  
Chi-Yun Lin ◽  
Matthew Romei ◽  
Luke Oltrogge ◽  
Irimpan Mathews ◽  
Steven Boxer
Keyword(s):  
Driving Force ◽  
Fluorescent Protein ◽  
Charge Transfer Band ◽  
Photophysical Properties ◽  
Polymethine Dyes ◽  
Emission Rates ◽  
Unified Framework ◽  
Underlying Factor ◽  
Green Fluorescent ◽  
Protein Environment

Green fluorescent protein (GFPs) have become indispensable imaging and optogenetic tools. Their absorption and emission properties can be optimized for specific applications. Currently, no unified framework exists to comprehensively describe these photophysical properties, namely the absorption maxima, emission maxima, Stokes shifts, vibronic progressions, extinction coefficients, Stark tuning rates, and spontaneous emission rates, especially one that includes the effects of the protein environment. In this work, we study the correlations among these properties from systematically tuned GFP environmental mutants and chromophore variants. Correlation plots reveal monotonic trends, suggesting all these properties are governed by one underlying factor dependent on the chromophore's environment. By treating the anionic GFP chromophore as a mixed-valence compound existing as a superposition of two resonance forms, we argue that this underlying factor is defined as the difference in energy between the two forms, or the driving force, which is tuned by the environment. We then introduce a Marcus-Hush model with the bond length alternation vibrational mode, treating the GFP absorption band as an intervalence charge transfer band. This model explains all the observed strong correlations among photophysical properties; related subtopics are extensively discussed in Supporting Information. Finally, we demonstrate the model's predictive power by utilizing the additivity of the driving force. The model described here elucidates the role of the protein environment in modulating photophysical properties of the chromophore, providing insights and limitations for designing new GFPs with desired phenotypes. We argue this model should also be generally applicable to both biological and non-biological polymethine dyes.<br>

Structural Evidence of Photoisomerization Pathways in Fluorescent Proteins

2019 ◽  
Author(s):  
Jeffrey Chang ◽  
Matthew Romei ◽  
Steven Boxer
Keyword(s):  
Rational Design ◽  
Fluorescent Protein ◽  
Fluorescent Proteins ◽  
Super Resolution ◽  
Unit Cell Size ◽  
Chlorine Substituent ◽  
Gfp Chromophore ◽  
The One ◽  
Green Fluorescent ◽  
Super Resolution Microscopy

<p>Double-bond photoisomerization in molecules such as the green fluorescent protein (GFP) chromophore can occur either via a volume-demanding one-bond-flip pathway or via a volume-conserving hula-twist pathway. Understanding the factors that determine the pathway of photoisomerization would inform the rational design of photoswitchable GFPs as improved tools for super-resolution microscopy. In this communication, we reveal the photoisomerization pathway of a photoswitchable GFP, rsEGFP2, by solving crystal structures of <i>cis</i> and <i>trans</i> rsEGFP2 containing a monochlorinated chromophore. The position of the chlorine substituent in the <i>trans</i> state breaks the symmetry of the phenolate ring of the chromophore and allows us to distinguish the two pathways. Surprisingly, we find that the pathway depends on the arrangement of protein monomers within the crystal lattice: in a looser packing, the one-bond-flip occurs, whereas in a tighter packing (7% smaller unit cell size), the hula-twist occurs.</p><p> </p><p> </p><p> </p><p> </p><p> </p><p> </p> <p> </p>

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