scholarly journals A Pattern Recognition Tool for Quantitative Analysis of In Planta Hyphal Growth of Powdery Mildew Fungi

2005 ◽  
Vol 18 (9) ◽  
pp. 906-912 ◽  
Author(s):  
U. Seiffert ◽  
P. Schweizer
Keyword(s):  
Growth Rate ◽  
Pattern Recognition ◽  
Quantitative Analysis ◽  
Powdery Mildew ◽  
Growth Rates ◽  
Fungal Pathogens ◽  
Hyphal Growth ◽  
Blumeria Graminis ◽  
In Planta ◽  
Powdery Mildew Fungi

The development of fungal pathogens can be quantified easily at the level of spore germination or penetration. However, the exact quantification of hyphal growth rates after initial, successful host invasion is much more difficult. Here, we report on the development of a new pattern recognition software (HyphArea) for automated quantitative analysis of hyphal growth rates of powdery mildew fungi on plant surfaces that usually represent highly irregular and noisy image backgrounds. By using HyphArea, we measured growth rates of colonies of the barley powdery mildew, Blumeria graminis f. sp. hordei, on susceptible and induced-resistant host plants. Hyphal growth was not influenced by the resistance state of the plants up to 48 h postinoculation. At later time points, growth rate increased on susceptible plants, whereas it remained restricted on induced-resistant plants. This difference in hyphal growth rate was accompanied by lack of secondary haustoria formation on induced-resistant plants, suggesting that induced resistance in barley against Blumeria graminis is caused mainly by reduced penetration rates of primary as well as secondary appressoria leading, finally, to fewer and lessdeveloped fungal colonies. No evidence was found for reduced nutrient-uptake efficiency of the primary haustoria in induced-resistant leaves, which would be expected to have resulted in reduced hyphal growth rates during the first 48 h of the interaction.

Quantitative and Physiological Analyses of Chloride Dependence of Growth of Halobacillus halophilus

1998 ◽  
Vol 64 (10) ◽  
pp. 3813-3817 ◽  
Author(s):  
Markus Roeßler ◽  
Volker Müller
Keyword(s):  
Growth Rate ◽  
Quantitative Analysis ◽  
Growth Rates ◽  
Chloride Concentration ◽  
Optimal Growth ◽  
Uptake System ◽  
Chloride Uptake ◽  
Molecular Masses ◽  
Final Yield ◽  
Energy Dependent

ABSTRACT A quantitative analysis of the Cl− dependence of growth of Halobacillus halophilus was performed. Optimal growth rates were obtained at Cl− concentrations of between 0.5 and 2.0 M, and the final yield was also strictly dependent on the Cl− concentration. Br− but not I−, SO4 2−, NO2 −, SO2 −, OCN−, SCN−, BO2 −, or BrO3 − could substitute for Cl−. To analyze the function of chloride, chloride concentration was determined. At low external Cl− (Cle −) concentrations, the growth rate was low and Cl− was excluded from the cytoplasm; increasing the Cle −concentration led to an increase in the growth rate and an energy-dependent uptake of Cl−, thus decreasing the Cle −/internal Cli − gradient from ≥10 at 0.1 M Cle − to a nearly constant value of 2 at Cle − concentrations which allowed optimal growth. Two membrane proteins with apparent molecular masses of 31 and 16 kDa which were identified to be specific for Cl−-grown cultures are possible candidates for a chloride uptake system.

Graminicolous powdery mildew fungi as new natural hosts of Ampelomyces mycoparasites

1997 ◽  
Vol 75 (4) ◽  
pp. 680-683 ◽  
Author(s):  
Levente Kiss
Keyword(s):  
Powdery Mildew ◽  
Poa Pratensis ◽  
Blumeria Graminis ◽  
Erysiphe Graminis ◽  
Natural Occurrence ◽  
Powdery Mildews ◽  
Two Samples ◽  
Natural Hosts ◽  
Powdery Mildew Fungi ◽  
Cultivated Species

The natural occurrence of Ampelomyces mycoparasites is reported for the first time in hyphae, conidiophores, and immature cleistothecia of Blumeria graminis (syn. Erysiphe graminis), the causal agent of cereal and grass powdery mildews. During a 4-year search for Ampelomyces on leaves of different wild and cultivated species of the Gramineae infected with powdery mildews in Hungary, Ampelomyces was recorded in only two samples that represent 5% of the collected monocotyledons. The host plants of B. graminis parasitized by Ampelomyces were Hordeum murinum and Poa pratensis. The pycnidia of Ampelomyces were present in only 3–10% of the powdery mildew mycelia. These observations suggest that (i) the natural occurrence of Ampelomyces mycoparasites on monocotyledons infected with powdery mildews is rare compared with their repeatedly reported incidence on dicotyledons infected with different powdery mildew fungi, and (ii) they probably do not have any significant role in the natural control of B. graminis in the field. Key words: Ampelomyces, Blumeria graminis, Erysiphe graminis, Gramineae, hyperparasitism, mycoparasitism.

scholarly journals First Report of Powdery Mildew Caused by an Oidium sp. on Torenia fournieri

Plant Disease ◽  
1999 ◽  
Vol 83 (9) ◽  
pp. 878-878 ◽  
Author(s):  
G. E. Holcomb
Keyword(s):  
Powdery Mildew ◽  
Infected Plant ◽  
Hyphal Growth ◽  
The United States ◽  
Plant Leaves ◽  
Torenia Fournieri ◽  
Bedding Plant ◽  
Leaf Surfaces ◽  
Powdery Mildew Fungi ◽  
Leaf Distortion

Torenia fournieri Lind. ex Fourn. (wishbone flower, bluewings) is a popular summer bedding plant in Louisiana. Clown Mixture cultivars are available in garden centers in March and April. Transplants of cultivar Clown Rose were purchased, transplanted to larger pots, and maintained in a greenhouse. A powdery mildew was observed on these plants in March and all plants (six) were severely diseased by May. Symptoms included leaf distortion and yellowing. Powdery mildew was not present on transplants and none was found in later checks of garden centers. An Oidium sp. was observed sporulating on both leaf surfaces of infected plants. Conidia were ellipsoid, produced in chains, lacked fibrosin bodies, and averaged 41 × 22 μm in dimensions. No sexual stage was observed. Healthy plants of Clown Mixture cultivars were obtained and inoculated by brushing conidia from infected plant leaves to leaves of healthy plants. Plants were maintained in a greenhouse where temperatures ranged from 16 to 26°C. Hyphal growth appeared on inoculated plants after 5 days and the reproductive structures formed later appeared the same as those on originally infected plants. Uninoculated plants remained healthy. No previous reports of powdery mildew diseases of T. fournieri in the United States were found. Other powdery mildew pathogens reported on T. fournieri are Sphaerotheca fuliginea (Schlechtend.:Fr.) Pollacci in Finland and Japan and an Erysiphe sp. in Japan (1). Reference: (1) K. Amano. Host Range and Geographical Distribution of the Powdery Mildew Fungi. Japan Scientific Press, Tokyo, 1986.

scholarly journals Powdery mildew fungi (Erysiphales, Ascomycota) of Western Polissya of Ukraine

2021 ◽  
Vol 78 (6) ◽  
pp. 381-398
Author(s):  
V.P. Heluta ◽  
◽  
I.M. Anishchenko ◽  
Keyword(s):  
Powdery Mildew ◽  
Rare Species ◽  
Common Species ◽  
Blumeria Graminis ◽  
History Of Research ◽  
History Of ◽  
Powdery Mildew Fungi ◽  
First Time

Information on powdery mildew fungi (Erysiphales, Ascomycota) recorded in Western Polissya of Ukraine throughout the history of research in the region is provided. The list included in the article comprises 85 species of 7 genera of Erysiphales, namely 43 species of Erysiphe, 19 of Golovinomyces, 15 of Podosphaera, three of Phyllactinia, two of Neoerysiphe and Sawadaea, and one species of Blumeria. For the first time, 21 species are reported for the region: Erysiphe astragali, E. azaleae, E. howeana, E. hypophylla, E. lycopsidis, E. macleayae, E. prunastri, E. russellii, E. syringae-japonicae, Golovinomyces ambrosiae, G. asterum, G. bolayi, G. fisheri, G. riedlianus, G. verbasci, Neoerysiphe galii, Phyllactinia fraxini, Podosphaera aucupariae, P. phtheirospermi, P. prunicola, and Sawadaea tulasnei. The most common species were Blumeria graminis, Erysiphe alphithoides, E. aquilegiae, E. divaricata, E. ornata, E. polygoni, Podosphaera aphanis, and P. myrtillina. Erysiphe heraclei, Neoerysiphe galeopsidis, and Podosphaera erigerontis-canadensis were recorded quite frequently. Erysiphe arcuata, E. astragali, E. azaleae, E. baeumleri, E. circaeae, E. cruchetiana, E. cruciferarum, E. grosulariae, E. hypophylla, E. lythri, E. macleayae, E. palczewskii, E. penicillata, E. pisi, E. prunastri, E. russellii, E. vanbruntiana, Golovinomyces ambrosiae, G. asterum, G. circumfusus, G. cynoglossi, G. fisheri, G. inulae, G. riedlianus, G. verbasci, Neoerysiphe galii, Phyllactinia fraxini, Ph. guttata s.str., Podosphaera amelanchieris, P. aucupariae, P. balsaminae, P. macularis, P. mors-uvae, P. prunicola, and Sawadaea tulasnei are known from one or two localities, so they are considered as rare species in Western Polissya of Ukraine.

scholarly journals Fungicide Resistance in Powdery Mildew Fungi

2020 ◽  
Vol 8 (9) ◽  
pp. 1431
Author(s):  
Alejandra Vielba-Fernández ◽  
Álvaro Polonio ◽  
Laura Ruiz-Jiménez ◽  
Antonio de Vicente ◽  
Alejandro Pérez-García ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Fungal Pathogens ◽  
Molecular Mechanisms ◽  
Resistance Development ◽  
Development Of Resistance ◽  
Powdery Mildews ◽  
Powdery Mildew Fungi ◽  
Sterol Demethylation Inhibitors ◽  
Chemical Groups ◽  
Multiple Chemical

Powdery mildew fungi (Erysiphales) are among the most common and important plant fungal pathogens. These fungi are obligate biotrophic parasites that attack nearly 10,000 species of angiosperms, including major crops, such as cereals and grapes. Although cultural and biological practices may reduce the risk of infection by powdery mildew, they do not provide sufficient protection. Therefore, in practice, chemical control, including the use of fungicides from multiple chemical groups, is the most effective tool for managing powdery mildew. Unfortunately, the risk of resistance development is high because typical spray programs include multiple applications per season. In addition, some of the most economically destructive species of powdery mildew fungi are considered to be high-risk pathogens and are able to develop resistance to several chemical classes within a few years. This situation has decreased the efficacy of the major fungicide classes, such as sterol demethylation inhibitors, quinone outside inhibitors and succinate dehydrogenase inhibitors, that are employed against powdery mildews. In this review, we present cases of reduction in sensitivity, development of resistance and failure of control by fungicides that have been or are being used to manage powdery mildew. In addition, the molecular mechanisms underlying resistance to fungicides are also outlined. Finally, a number of recommendations are provided to decrease the probability of resistance development when fungicides are employed.

Time series analysis demonstrates the absence of pulsatile hyphal growth

Microbiology ◽  
2003 ◽  
Vol 149 (11) ◽  
pp. 3111-3119 ◽  
Author(s):  
Karina Sampson ◽  
Roger R. Lew ◽  
I. Brent Heath
Keyword(s):  
Growth Rate ◽  
Time Series ◽  
Growth Rates ◽  
Tip Growth ◽  
Hyphal Growth ◽  
Pollen Tubes ◽  
Saprolegnia Ferax ◽  
Hyphal Tip Growth ◽  
Rigorous Statistical Analysis ◽  
Hyphal Tip

Hyphal tip growth has been previously reported as pulsatile, defined as regularly alternating fast and slow rates of extension. The growth of pollen tubes, and hyphae of Neurospora crassa and Saprolegnia ferax were analysed using high spatial and temporal resolution. By using long (100–500 s) records of growth rate, sampled every second, it was possible to apply rigorous statistical analysis of the time series. As previously demonstrated, pollen tubes can show pulsatile growth, detectable with this system. In contrast, hyphal growth rates do not show any evidence of pulsatile growth; instead, growth rates appear to fluctuate randomly. It is concluded that pulsatile growth is not a common feature of hyphal tip growth.

Microscopy studies of powdery mildew on summer squash

1991 ◽  
Vol 49 ◽  
pp. 520-521
Author(s):  
John S. Gardner ◽  
W. M. Hess
Keyword(s):  
Powdery Mildew ◽  
Tip Growth ◽  
Hyphal Growth ◽  
Plant Tissues ◽  
Vegetative Hypha ◽  
Powdery Mildews ◽  
Summer Squash ◽  
Conidial Formation ◽  
Polar Tip Growth ◽  
Short Conidiophore

Powdery mildews are characterized by the appearance of spots or patches of a white to grayish, powdery, mildewy growth on plant tissues, entire leaves or other organs. Ervsiphe cichoracearum, the powdery mildew of cucurbits is among the most serious parasites, and the most common. The conidia are formed similar to the process described for Ervsiphe graminis by Cole and Samson. Theconidial chains mature basipetally from a short, conidiophore mother-cell at the base of the fertile hypha which arises holoblastically from the conidiophore. During early development it probably elongates by polar-tip growth like a vegetative hypha. A septum forms just above the conidiophore apex. Additional septa develop in acropetal succession. However, the conidia of E. cichoracearum are more doliform than condia from E. graminis. The purpose of these investigations was to use scanning electron microscopy (SEM) to demonstrate the nature of hyphal growth and conidial formation of E. cichoracearum on field-grown squash leaves.

Sign in / Sign up

Export Citation Format

Share Document