scholarly journals Osmotin and Thaumatin from Grape: A Putative General Defense Mechanism Against Pathogenic Fungi

2003 ◽  
Vol 93 (12) ◽  
pp. 1505-1512 ◽  
Author(s):  
Sara Monteiro ◽  
Mahmoud Barakat ◽  
Maria A. Piçarra-Pereira ◽  
Artur R. Teixeira ◽  
Ricardo B. Ferreira
Keyword(s):  
Botrytis Cinerea ◽  
Spore Germination ◽  
Germ Tube ◽  
Defense Mechanism ◽  
Pr Proteins ◽  
Tube Growth ◽  
Immunological Methods ◽  
Phomopsis Viticola ◽  
Germ Tube Growth

Little information is available concerning the expression of pathogenesis-related (PR) proteins in grapevine (Vitis vinifera) and their effect properties on the major fungal pathogens of grape. A systematic study was performed on the effect of total or individual grape proteins on mycelial growth, spore germination, and germ tube growth of Uncinula necator, Phomopsis viticola, and Botrytis cinerea. Two proteins, identified as PR proteins by immunological methods and by N-terminal sequencing as osmotin and thaumatin-like protein, exhibited strong antifungal activities in vitro, blocking the growth of Phomopsis viticola and Botrytis cinerea mycelia. In addition, they inhibited spore germination and germ tube growth of U. necator, Phomopsis viticola, and Botrytis cinerea. The presence of both proteins displayed a synergistic effect. The expression of osmotin and thaumatin-like protein was induced in grapevine leaves and berries infected with U. necator and Phomopsis viticola. Thaumatin previously was thought to occur exclusively in berries. Immunoblot analyses revealed the accumulation of the two PR proteins in infected leaves and berries, supporting a role in vivo in increasing the resistance of grapevine to fungal attack.

Comparison of germination of Cladosporium herbarum and Botrytis cinerea conidia in vitro in relation to nutrient conditions on leaf surfaces

1981 ◽  
Vol 59 (5) ◽  
pp. 854-861 ◽  
Author(s):  
H. G. Wildman ◽  
D. Parkinson
Keyword(s):  
Botrytis Cinerea ◽  
Germ Tube ◽  
Nitrate Solution ◽  
Potassium Nitrate ◽  
Tube Growth ◽  
Nitrogen Levels ◽  
Cladosporium Herbarum ◽  
Leaf Surfaces ◽  
Germ Tube Growth

Conidia of Cladosporium herbarum and Botrytis cinerea differed in their ability to germinate in water. Potassium nitrate, glucose, and carbohydrate mixtures at concentrations similar to carbon and nitrogen levels on leaf surfaces were tested for their effect on germination and subsequent germ tube growth. For both fungi, all the treatments increased the rate of germination. The treatments also stimulated the total percentage germination of C. herbarum conidia. Glucose, a glucose – potassium nitrate solution, and carbohydrate mixtures stimulated both germ tube production and total germ tube lengths of conidia of C. herbarum. Botrytis cinerea conidia produced multiple germ tubes per conidium in distilled water, potassium nitrate, and carbohydrate mixtures. Glucose and glucose – potassium nitrate solutions stimulated production of a single germ tube per conidium. All treatments stimulated germ tube growth of B. cinerea conidia.

scholarly journals In vitro effect of substrate, temperature and photoperiod on Phakopsora pachyrhizi urediniospore germination and germ tube growth

2015 ◽  
Vol 41 (2) ◽  
pp. 101-106
Author(s):  
Marta Maria Casa Blum ◽  
Erlei Melo Reis ◽  
Francieli Tavares Vieira ◽  
Rita Carlini
Keyword(s):  
Substrate Temperature ◽  
Spore Germination ◽  
Leaf Extract ◽  
Germ Tube ◽  
Tube Growth ◽  
Tube Length ◽  
Germ Tube Length ◽  
Soybean Leaf ◽  
Germ Tube Growth

In vitro experiments were conducted to assess the effects of substrate, temperature and time of exposure to temperature and photoperiod on P. pachyrhizi uredospore germination and germ tube growth. The following substrates were tested: water-agar and soybean leaf extract-agar at different leaf concentrations (0.5, 1.0, 2.0 and 4.0 g of leaves and 15g agar/L water), temperatures (10, 15, 20, 25, 30, and 35oC) and times of exposure (1, 2, 3, 4, 5, 6, 7, and 8 hours) to temperature and 12 different photoperiods. The highest germination and germ tube length was found for the soybean leaf extract agar. Maximum P. pachyrhizi uredospore germination was obtained at 21.8 and 22.3°C, and maximum germ tube growth at 21.4 and 22.1°C. The maximum uredospore germination was found at 6.4 hours exposure, while the maximum germ tube length was obtained at 7.7 h exposure. Regarding photoperiod, the maximum spore germination and the maximum uredospore germ tube length were found in the dark. Neither spore germination nor uredospore germ tube growth was completely inhibited by the exposure to continuous light.

Effect of light exposure on in vitro germination and germ tube growth of eight species of rust fungi

Mycologia ◽  
2010 ◽  
Vol 102 (5) ◽  
pp. 1134-1140 ◽  
Author(s):  
James W. Buck ◽  
Weibo Dong ◽  
Daren S. Mueller
Keyword(s):  
Germ Tube ◽  
Light Exposure ◽  
Rust Fungi ◽  
Tube Growth ◽  
In Vitro Germination ◽  
Effect Of Light ◽  
Germ Tube Growth

The effect of temperature on in vitro germination and germ tube growth of urediniospores of Tranzschelia discolor

1990 ◽  
Vol 41 (3) ◽  
pp. 479 ◽  
Author(s):  
PJ Ellison ◽  
BR Cullis ◽  
RW Bambach ◽  
PF Kable
Keyword(s):  
Germ Tube ◽  
Three Dimensional ◽  
Tube Growth ◽  
Effect Of Temperature ◽  
In Vitro Germination ◽  
Three Dimensional Models ◽  
C 30 ◽  
Tranzschelia Discolor ◽  
Germ Tube Growth

The effect of temperature on in vitro germination and germ tube growth of urediniospores of Tranzschelia discolor was studied over time under constant temperature conditions. Studies were carried out on 1% water agar in the dark at 3�C, 5�C, 8�C, 10�C, 15�C, 20�C, 25�C, 28�C, 30�C and 32�C. Germination was observed at all temperatures between 5 and 30'C, and occurred rapidly over most of this range. At 2 h, germination exceeded 80% at temperatures between 10 and 28�C, and this level was reached at 3 h at 8�C. Germination at 5 and 30�C was much reduced and at 7 h reached only 44% and 38% respectively. Germ tube growth occurred most vigorously at 15 and 20�C, reaching lengths in excess of 500 8m at 9 h. The optimum range was narrower than that for germination, and growth was reduced or poor at 8�C, 10�C, 25�C and 28�C, which were favourable temperatures for germination. Average germ tube lengths at 9 h at these temperatures were 55, 245, 273 and 62 8m, respectively. Three-dimensional models were derived relating germination and germ tube growth to time and temperature.

Effect of treatment with the phytoalexins medicarpin and maackiain on fungal growth in vitro and in vivo

1976 ◽  
Vol 54 (23) ◽  
pp. 2620-2629 ◽  
Author(s):  
Lorne J. Duczek ◽  
Verna J. Higgins
Keyword(s):  
Oxygen Uptake ◽  
Germ Tube ◽  
Protective Action ◽  
Fungal Growth ◽  
Red Clover ◽  
Tube Growth ◽  
Effect Of Treatment ◽  
Germ Tube Growth

The effect of medicarpin (3-hydroxy-9-methoxypterocarpan) and maackiain (3-hydroxy-8,9-methylenedioxypterocarpan). phytoalexins from red clover, on germ tube growth, oxygen uptake, and pathogenicity of Helminthosporium carbonum, Stemphylium botryosum, and S. sarcinaeforme was examined. Germ tube growth of all three fungi was inhibited by as little as 10 μg/ml of these compounds and oxygen uptake by H. carbonum and S. botryosum, but not by S. sarcinaeforme, was reduced by higher concentrations (about 60 μg/ml) of these phytoalexins. Medicaipin and maackiain added to inoculum drops prevented H. carbonum from infecting its host plant, corn. This protective effect was probably caused by the failure of H. carbonum to form appressoria in the presence of the phytoalexins. No protective action of the phytoalexins was noted when either S. botryosum or S. sarcinaeforme was used on their host plants, alfalfa and clover, respectively. Inoculation of red clover leaves with the nonpathogen H. carbonum before inoculation with the pathogen S. sarcinaeforme had no effect on symptom development, nor was there any evidence of increased susceptibility to H. carbonum if either S. sarcinaeforme or S. botryosum was added at the time of inoculation. The results are discussed in relation to the role of these phytoalexins in disease resistance of red clover.

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