Effects of temperature and antibiotics on appressorium formation in spores of Colletotrichum lagenarium

1977 ◽  
Vol 23 (5) ◽  
pp. 626-629 ◽  
Author(s):  
Machiko Tani ◽  
Norio Ishida ◽  
Iwao Furusawa
Keyword(s):  
Spore Germination ◽  
Germ Tube ◽  
Temperature Treatment ◽  
Appressorium Formation ◽  
Colletotrichum Lagenarium ◽  
Effects Of Temperature ◽  
Blasticidin S

Effects of temperature (32 °C), cycloheximide, and blasticidin-S on spore germination and appressorium formation of Colletotrichum lagenarium were investigated. Temperature treatment at 32 °C, given just before the emergence of the germ tube 4 h after incubation at 24 °C, significantly inhibited appressorium formation. Cycloheximide (1 ppm) or blasticidin-S (7 ppm) appeared to have reversed the effect of 32 °C treatment by producing appressoria in 30% of the germinated spores.

Studies on Graminicolous Species of Phyllachora Fckl. I. Ascospores - their liberation and germination

1963 ◽  
Vol 11 (2) ◽  
pp. 117 ◽  
Author(s):  
DG Parbery
Keyword(s):  
Spore Germination ◽  
Germ Tube ◽  
Leaf Surface ◽  
Individual Species ◽  
Appressorium Formation ◽  
Rain Splash ◽  
First Time ◽  
Germ Tubes ◽  
Appressorium Development

The process of ascospore liberation is a moderately active one. Discharged ascospores collect on the host leaf surface in white, glutinous masses and are believed to be dispersed by rain splash. Ascospores of all species examined germinated in 2-12 hr at 14°C under laboratory conditions, but there were indications that the process was more rapid in the field. The pattern for spore germination and appressorium formation was similar for the six species studied. Each ascospore produced a single germ tube which, in 2-6 hr after germination began, formed an appressorium initial in the form of a swelling at its apex. Appressoria were completely developed 6-12 hr later. The process of appressorium development is described for species of Phyllachora for the first time. The swelling at the apex of the germ tube extended back along the germ tube towards the ascspore. In some species, e.g. P. cornispora, the entire germ tube was converted into an appressorium which consequently was sessile. In other species, such as P. parilis, only approximately half of the germ tube developed into appressorium. In P. parilis, temperatures greater than 26°C inhibited appressorium formation. Instead of producing appressoria, germ tubes continued to grow and became long and flexuous. Germination did not occur at temperatures of 30°C or greater. Evidence suggested that while contact with a surface was not necessary to initiate appressorium formation, contact with a grass leaf surface was required for appressoria to develop normally. The morphology of appressoria of individual species of Phyllachora was usually variable when these structures developed in vitro but constant and distinct when they developed on the host. Among the species examined three basic morphological types of appressoria were recognized.

Aliphatic acids as spore germination inhibitors of wood-decay fungi in vitro

1985 ◽  
Vol 63 (2) ◽  
pp. 337-339 ◽  
Author(s):  
Elmer L. Schmidt
Keyword(s):  
Spore Germination ◽  
Germ Tube ◽  
White Rot Fungi ◽  
Wood Decay ◽  
White Rot ◽  
Malt Extract ◽  
Decay Fungi ◽  
Aliphatic Acids ◽  
Wood Decay Fungi

Influences of eight saturated aliphatic acids (C5–C10, C12, and C16) on basidiospores of four isolates of wood-decay fungi (Poria tenuis and Trametes hispida, white rot fungi, and two isolates of the brown rot fungus Gloeophyllum trabeum) were observed in vitro. Spore responses after 24 h on malt extract agar containing 10, 102 or 103 ppm of each acid included normal germination, delay of germ tube emergence, vacuolation and degeneration of spore cytoplasm, and prevention of germ tube development without spore destruction. Acids of chain length C5–C10 prevented spore germination and killed spores of all fungi at concentrations of 20–50 ppm in media, whereas other acids tested were less active. Spore germination assay of decay fungi may prove useful as a screening tool to compare potency of wood preservatives.

scholarly journals A Feed-Forward Subnetwork Emerging from Integrated TOR- and cAMP/PKA-Signaling Architecture Reinforces Magnaporthe oryzae Appressorium Morphogenesis

2019 ◽  
Vol 32 (5) ◽  
pp. 593-607 ◽  
Author(s):  
Guangchao Sun ◽  
Xiaobo Qi ◽  
Richard A. Wilson
Keyword(s):  
Cell Cycle ◽  
Adenylate Cyclase ◽  
Magnaporthe Oryzae ◽  
Environmental Conditions ◽  
Germ Tube ◽  
Nutrient Status ◽  
Specific Cell ◽  
Appressorium Formation ◽  
G2 Arrest ◽  
Feed Forward

Appressoria are important mediators of plant–microbe interactions. In the devastating rice blast pathogen Magnaporthe oryzae, appressorial morphogenesis from germ tube tips requires activated cAMP/PKA signaling and inactivated TOR signaling (TORoff). TORoff temporarily arrests G2 at a metabolic checkpoint during the single round of mitosis that occurs following germination. G2 arrest induces autophagy and appressorium formation concomitantly, allowing reprogression of the cell cycle to G1/G0 quiescence and a single appressorial nucleus. Inappropriate TOR activation abrogates G2 arrest and inhibits cAMP/PKA signaling downstream of cPKA. This results in multiple rounds of germ tube mitosis and the loss of autophagy and appressoria formation. How cAMP/PKA signaling connects to cell cycle progression and autophagy is not known. To address this, we interrogated TOR and cAMP/PKA pathways using signaling mutants, different surface properties, and specific cell cycle inhibitors and discovered a feed-forward subnetwork arising from TOR- and cAMP/PKA-signaling integration. This adenylate cyclase-cAMP-TOR-adenylate cyclase subnetwork reinforces cAMP/PKA-dependent appressorium formation under favorable environmental conditions. Under unfavorable conditions, the subnetwork collapses, resulting in reversible cell cycle-mediated germ tube growth regardless of external nutrient status. Collectively, this work provides new molecular insights on germ tube morphogenetic decision-making in response to static and dynamic environmental conditions.

scholarly journals Inhibition of Spore Germination and Appressorium Formation of Rust Species by Plant and Fungal Metabolites

2016 ◽  
Vol 11 (9) ◽  
pp. 1934578X1601100 ◽  
Author(s):  
Eleonora Barilli ◽  
Alessio Cimmino ◽  
Marco Masi ◽  
Marco Evidente ◽  
Diego Rubiales ◽  
...  
Keyword(s):  
Spore Germination ◽  
Cytochalasin B ◽  
Rust Fungi ◽  
Fungal Metabolites ◽  
Plant Leaves ◽  
Appressorium Formation ◽  
Plant Metabolites ◽  
Naturally Occurring ◽  
Detached Leaves ◽  
Appressoria Formation

Eight fungal and plant metabolites belonging to different classes of naturally occurring compounds, a 24-oxa[14]-cytochalasan as cytochalasin B (1), a trisubstituted isocoumarin as 6-hydroxymellein (2), a tetracyclic pimarane diterpene as sphaeropsidin A (3), a chalcone as cavoxin (4), a pentasubstituted benzofuranone as cyclopaldic acid (5), a bicyclic-sesquiterpene as inuloxin A (6), a epipolythiopiperazine as gliotoxin (7) and a cyclohexene epoxide as epi-epoformin (8), were tested for their effectiveness in reducing early stages of development of several major rust fungi from the genera Puccinia and Uromyces. Spore germination and appressoria formation were assessed on pre-treated detached leaves, under controlled conditions. Among the various metabolites evaluated, compounds 5 and 8 were the most effective in inhibiting fungal germination and penetration of all rust species studied at values comparable with those obtained by fungicide application, while compound 4 was phytotoxic to plant leaves at any concentration tested.

scholarly journals Antifungal Efficacy of Plant Oils Containing Thymol and Carvacrol in Controlling Botrytis cinerea, the Causal Agent of Grape (Vitis vinifera) GrayMould

2018 ◽  
Vol 16 (02) ◽  
pp. 15-24
Author(s):  
Zaker M ◽  
Zaker L
Keyword(s):  
Essential Oils ◽  
Botrytis Cinerea ◽  
Spore Germination ◽  
Mycelial Growth ◽  
Germ Tube ◽  
Plant Diseases ◽  
Plant Oils ◽  
Horticultural Products ◽  
Antifungal Efficacy ◽  
Germ Tube Elongation

The efficacy of a large number of plant extracts and essential oils in controlling plant diseases has been proven worldwide. Botrytis cinerea has attacked a wide host range causing severe loss in the field and at storage. In this study the antifungal efficacy of essential oils of three medicinal plants namely wild marjoram (Zataria multifolia), wild savory (perennial) (Satureja mutica) and savory (annual) (Satureja hortensis) possessing these compounds at three concentrations: 50, 100 and 200 ppm were evaluated in controlling the mycelial growth, spore germination and germ tube elongation of B. cinerea. All treatments except savory (annual) essential oil at 50 ppm showed significant differences with the control in inhibiting the mycelial growth as well as spore germination and germ tube elongation of B. cinerea (p=0.01). It was also noted that wild marjoram at 100 ppm and wild savory (perennial) essential oils at 200 ppm could completely (100%) inhibit the growth of the fungus. Essential oils from wild marjoram and wild savory had higher antifungal activity than annual savory. Their suitable formulations could be prepared and used as safe alternatives for controlling moulds of horticultural products during storage. The Agriculturists 2018; 16(2) 15-24

Factors influencing infection, colonization and symptom expression in barley by Rhynchosporium secalis

1974 ◽  
Vol 25 (1) ◽  
pp. 9 ◽  
Author(s):  
SM Ali
Keyword(s):  
High Temperature ◽  
Germ Tube ◽  
Leaf Tissue ◽  
Tube Growth ◽  
Rhynchosporium Secalis ◽  
Symptom Expression ◽  
West China ◽  
Effects Of Temperature ◽  
Resistant Genotypes ◽  
Germ Tube Growth

Germ tube growth and mycelium establishment of Rhynchosporium secalis, the causal agent of scald in barley, were studied in seven resistant and four susceptible barley hosts of known genotype. Although no visible symptoms were apparent, none of the resistant hosts were free from mycelium establishment in leaf tissue. The resistant hosts could be divided into two categories according to the rate of germ tube growth. The effect of host age, duration of incubation period, temperature, spore concentration, and pathogen age on symptom expression in the 11 genotypes was examined. Excluding the effects of temperature, the resistant genotypes could be grouped into (a) those expressing their resistance consistently, e.g. Psaknon, Atlas 46, Atlas 57, Hudson and Turk, and (b) those expressing their resistance inconsistently, e.g. West China and La Mesita. High temperature caused breakdown of resistance in Psaknon, Turk, Hudson and West China. The pathogenicity of one isolate (UWA307) was found to be impaired by high temperature. Implications of the above findings are discussed in relation to the disease situation in Western Australia.

scholarly journals Inhibitory effect of Pseudomonas spp. on the development of Botrytis cinerea and Penicillium expansum

2010 ◽  
Vol 40 (No. 4) ◽  
pp. 128-134 ◽  
Author(s):  
H. Bryk ◽  
B. Dyki ◽  
P. Sobiczewski
Keyword(s):  
Botrytis Cinerea ◽  
Spore Germination ◽  
Germ Tube ◽  
Inhibitory Effect ◽  
Penicillium Expansum ◽  
Bacterial Strains ◽  
Liquid Cultures ◽  
Pseudomonas Spp ◽  
Apple Leaves ◽  
Germ Tube Elongation

The influence of antagonistic Pseudomonas spp. on the development of Botrytis cinerea and Penicillium expansum was studied in liquid cultures. Two strains of Pseudomonas spp. (B194 and B224), originally isolated from apple leaves and fruits, respectively, inhibited spore germination and germ tube elongation of B. cinerea or P. expansum. The inhibitory effect depended on the concentration of bacteria in the cultures. After a prolonged time of incubation (48–76 h) lysis and fragmentation of hyphae of both fungi was observed. In some cases the hyphae of B. cinerea developed abnormally if the bacterial strains were present – the hyphal tips were swollen and ball-shaped spore-like structures aggregated in chains were formed.

Sensitivity of spore germination and germ tube elongation of Saccharina japonica to metal exposure

Ecotoxicology ◽  
2011 ◽  
Vol 20 (8) ◽  
pp. 2056-2068 ◽  
Author(s):  
Taejun Han ◽  
Jeong-Ae Kong ◽  
Hee-Gyu Kang ◽  
Seon-Jin Kim ◽  
Gyo-Sun Jin ◽  
...  
Keyword(s):  
Spore Germination ◽  
Germ Tube ◽  
Saccharina Japonica ◽  
Metal Exposure ◽  
Germ Tube Elongation

Cold exposure of Southdown and Welsh Mountain sheep. 4. Changes in concentrations of free fatty acids, glucose, acetone, protein-bound iodine, protein and antibody in the blood

1969 ◽  
Vol 11 (4) ◽  
pp. 479-491 ◽  
Author(s):  
R. Halliday ◽  
A. R. Sykes ◽  
J. Slee ◽  
A. C. Field ◽  
A. J. F. Russel
Keyword(s):  
Serum Protein ◽  
Cold Exposure ◽  
Temperature Treatment ◽  
Acute Exposure ◽  
Protein Levels ◽  
Glucose Levels ◽  
Acute Cold Exposure ◽  
Effects Of Temperature ◽  
Antibody Levels ◽  
Female Sheep

SUMMARYTwenty-four Southdown and 24 Welsh Mountain year-old female sheep, half on high-plane and half on low-plane nutrition, were shorn and given two acute cold exposures in climate chambers. For 2 weeks before and 2 weeks between exposures the sheep were kept in a subcritical (+ 8°C) or a thermoneutral (+30°C) environment. Before the temperature treatment each sheep received an injection of Brucella abortus vaccine. Blood samples were taken during exposure to + 8°C and + 30°C and during the acute cold exposures for estimation of free fatty acid (FFA), protein-bound iodine (PBI), glucose, acetone, serum protein and antibody levels. FFA and glucose levels alone were measured in 32 similarly treated Scottish Blackface sheep.1. Low plane sheep had higher PBI levels at all temperatures, and higher glucose levels during acute cold exposure than high plane sheep. Otherwise most major effects were attributable to ambient temperature.2. At +8°C the PBI, FFA, glucose, serum protein and acetone levels were higher than at + 30°C.3. Blackface sheep had lower FFA and glucose levels than Southdown and Welsh sheep at both temperatures.4. During acute cold exposure, PBI, acetone and FFA levels increased further. PBI levels were highest in sheep previously at + 30°C, and acetone highest in sheep previously at + 8°C. Very high FFA levels were recorded, especially in sheep not previously cold-acclimatized.5. Glucose levels increased initially, but fell towards the end of acute exposure, suggesting that relatively less carbohydrate and more fat was utilized for energy metabolism during this period.6. Serum protein levels fell during acute exposure, possibly because protein catabolism increased. The proportions of albumin and γ-globulin increased and decreased respectively.7. No effects of temperature on antibody levels were detected.

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