PHYSIOLOGICAL AND CYTOLOGICAL STUDIES OF BASIDIOSPORE REPETITION IN RHIZOCTONIA SOLANI KÜHN

1964 ◽  
Vol 42 (10) ◽  
pp. 1397-1404
Author(s):  
H. S. Whitney
Keyword(s):  
Rhizoctonia Solani ◽  
Germ Tube ◽  
Thanatephorus Cucumeris ◽  
Germ Tubes

Mycelium of a clone of Thanatephorus cucumeris (Frank) Donk (Rhizoctonia solani Kühn) produced ether-soluble substances which, when incorporated into water agar, caused basidiospores to shift from germ tube development to repetition. Repetition activity was localized in chromatograms by bioassay. Germ tubes less than 48 hours old produced ballistospores when transferred from water agar to fruiting cultures. Cells of older hyphae had apparently lost this capacity. Repetition spores, and ballistospores produced by germ tubes, were uninucleate and gave rise to cultures typical of the parent fungus. The relevance of repetition to survival and to phylogeny was discussed.

Ascospore germination, growth in culture, and imperfect spore formation in Cookeina sulcipes and Phillipsia crispata

1975 ◽  
Vol 53 (1) ◽  
pp. 56-61 ◽  
Author(s):  
J. W. Paden
Keyword(s):  
Germ Tube ◽  
Outer Wall ◽  
Wall Layer ◽  
Spore Formation ◽  
Spore Surface ◽  
No Formation ◽  
Ascospore Germination ◽  
Germ Tubes

Ascospores of Cookeina sulcipes germinate by one of two modes: (1) by the production of blastoconidia on sympodially proliferating conidiogenous cells which may arise from any point on the spore surface, and (2) by a thick polar germ tube. No ascospores were seen to germinate both ways. The conidiogenous cells are occasionally modified into narrow hyphae. The blastoconidia germinate readily but are evidently very short-lived. Ascospores of Phillipsia crispata germinate by two polar germ tubes; there is no formation of blastoconidia. In both species the inner ascospore wall separated from an outer wall layer during germination. In culture both C. sulcipes and P. crispata form arthroconidia. The arthroconidia are uninucleate; they germinate readily and reproduce the species when transferred to fresh plates.

Carbon dioxide induces endotrophic germ tube formation in Candida albicans

1990 ◽  
Vol 36 (4) ◽  
pp. 249-253 ◽  
Author(s):  
Ruth C. Mock ◽  
Jordan H. Pollack ◽  
Tadayo Hashimoto
Keyword(s):  
Carbon Dioxide ◽  
Candida Albicans ◽  
Sodium Bicarbonate ◽  
Key Words ◽  
Germ Tube ◽  
Tube Formation ◽  
Chemical Inducers ◽  
Tube Emergence ◽  
Ph Range ◽  
Germ Tubes

Candida albicans formed germ tubes when exposed to air containing 5 to 15% carbon dioxide (CO2). The CO2-mediated germ tube formation occurred optimally at 37 °C in a pH range of 5.5 to 6.5. No germ tubes were produced at 25 °C, even when the optimal concentration of CO2 (10%) was present in the environment. The requirement of CO2 for germ tube formation could be partially substituted by sodium bicarbonate but not by N2. Carbon dioxide was required to be present throughout the entire course of germ tube emergence suggesting that its role is not limited to an initial triggering of morphogenic change. We suggest that carbon dioxide may be a common effector responsible for the germ tube promoting activity of certain chemical inducers for C. albicans. Key words: Candida albican germ tubes, CO2-induced germ tube formation, endotrophic germ tube formation.

scholarly journals Regulation of Pathogenic Spore Germination by CgRac1 in the Fungal Plant Pathogen Colletotrichum gloeosporioides

2011 ◽  
Vol 10 (8) ◽  
pp. 1122-1130 ◽  
Author(s):  
Iris Nesher ◽  
Anna Minz ◽  
Leonie Kokkelink ◽  
Paul Tudzynski ◽  
Amir Sharon
Keyword(s):  
Cell Division ◽  
Plant Pathogen ◽  
Germ Tube ◽  
Colletotrichum Gloeosporioides ◽  
Fluorescent Protein ◽  
Nuclear Division ◽  
Simultaneous Formation ◽  
Content Type ◽  
Germ Tubes

ABSTRACT Colletotrichum gloeosporioides is a facultative plant pathogen: it can live as a saprophyte on dead organic matter or as a pathogen on a host plant. Different patterns of conidial germination have been recognized under saprophytic and pathogenic conditions, which also determine later development. Here we describe the role of CgRac1 in regulating pathogenic germination. The hallmark of pathogenic germination is unilateral formation of a single germ tube following the first cell division. However, transgenic strains expressing a constitutively active CgRac1 (CA-CgRac1) displayed simultaneous formation of two germ tubes, with nuclei continuing to divide in both cells after the first cell division. CA-CgRac1 also caused various other abnormalities, including difficulties in establishing and maintaining cell polarity, reduced conidial and hyphal adhesion, and formation of immature appressoria. Consequently, CA-CgRac1 isolates were completely nonpathogenic. Localization studies with cyan fluorescent protein (CFP)-CgRac1 fusion protein showed that the CgRac1 protein is abundant in conidia and in hyphal tips. Although the CFP signal was equally distributed in both cells of a germinating conidium, reactive oxygen species accumulated only in the cell that produced a germ tube, indicating that CgRac1 was active only in the germinating cell. Collectively, our results show that CgRac1 is a major regulator of asymmetric development and that it is involved in the regulation of both morphogenesis and nuclear division. Modification of CgRac1 activity disrupts the morphogenetic program and prevents fungal infection.

Emergence of the aeciospore germ tubes of Cronartium coleosporioides (=Peridermium stalactiforme) as observed by scanning electron microscope

1970 ◽  
Vol 48 (9) ◽  
pp. 1692-1692 ◽  
Author(s):  
Y. Hiratsuka
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Germ Tube ◽  
Germ Tubes ◽  
Scanning Electron

Germ tubes of Cronartium coleosporioides Arth. (= Peridermium stalactiforme Arth. and Kern) emerged between processes through short irregular slits. Germ tube walls were folded when they emerged and expanded after the emergence.

Behavior of Fusarium roseum 'Sambucinum' under carbon starvation conditions in relation to survival in soil

1969 ◽  
Vol 15 (1) ◽  
pp. 117-126 ◽  
Author(s):  
G. J. Griffin ◽  
T. Pass
Keyword(s):  
Latent Period ◽  
Direct Observation ◽  
Germ Tube ◽  
Carbon Starvation ◽  
Glucose Medium ◽  
Glucose Depletion ◽  
High Germination ◽  
Germ Tubes ◽  
Starvation Conditions ◽  
Exogenous Source

Direct observation of washed macroconidia of F. roseum 'Sambucinum' infested in rewetted soil and incubated at 6 °C indicated that germination increased to 79% at 4 days and increased slowly thereafter. Lysis of germ tubes was inhibited and most germ tubes were not lysed even after 48 days incubation. Small two- or three-celled macroconidia were commonly produced on germ tubes. In contrast, peak germination (39%) occurred at 2 days in rewetted soil incubated at 25 °C with germ tube lysis occurring rapidly between 4 and 8 days. Only sparse sporulation was observed. After 9 months, survival of F. roseum 'Sambucinum' was much greater in soil incubated at 6 °C than at 25 °C.Macroconidia required an exogenous source of carbon for high germination and formed one- or two-celled chlamydosporic macroconidia in media lacking exogenous carbon. After 9 months incubation under carbon starvation conditions at 25 °C chlamydosporic macroconidia had a longer latent period and a much slower rate of germination than macroconidia. Germinated macroconidia formed two- or three-celled macroconidia within 24 h when transferred to media lacking exogenous carbon. Four-celled macroconidia were produced by F. roseum 'Sambucinum' in a dilute glucose medium before exhaustion of the glucose while F. solani 'Coeruleum' formed chlamydospores in this medium after glucose depletion. Behavior of F. roseum 'Sambucinum' under carbon starvation conditions is similar to behavior in rewetted soil in the mode of sporulation and in the formation of chlamydosporic macroconidia, but differs by a lack of appreciable germination and by a greatly reduced lysis of fungal structures.

Interaction of culture age and temperature on germination and growth of Curvularia geniculata and on virulence

1972 ◽  
Vol 50 (11) ◽  
pp. 2093-2096 ◽  
Author(s):  
Clinton F. Hodges
Keyword(s):  
Germ Tube ◽  
Culture Age ◽  
Germination And Growth ◽  
Germ Tubes

Germination of conidia of Curvularia geniculata from 20-, 40-, and 60-day-old cultures increased as temperature was increased to 15C. At 25C, maximum germination occurred among conidia from 20-day-old cultures, but germination from 40- and 60-day-old cultures decreased at and above 25C. Number and length of germ tubes and primary germ-tube branches increased on all conidia as temperature was increased from 5C to 25C and decreased above 25C. Germination also was influenced by culture age. Total and rate of germination decreased among conidia from older cultures at all temperatures; number and length of germ tubes and germ-tube branches also decreased on conidia from older cultures. Pathogenicity of C. geniculata was not clearly established.

Sign in / Sign up

Export Citation Format

Share Document