CYTOLOGY OF THE AECIOSPORES AND AECIOSPORE GERM TUBES OF PERIDERMIUM HARKNESSII AND P. STALACTIFORME OF THE CRONARTIUM COLEOSPORIOIDES COMPLEX

1966 ◽  
Vol 44 (12) ◽  
pp. 1639-1643 ◽  
Author(s):  
Y. Hiratsuka ◽  
W. Morf ◽  
J. M. Powell
Keyword(s):  
Life Cycle ◽  
Germ Tube ◽  
Nuclear Division ◽  
Nuclear Fusion ◽  
Septum Formation ◽  
Germ Tubes

Cytology of aeciospores and aeciospore germ tubes of two pine rusts, Peridermium harknessii J. P. Moore and P. stalactiforme Arth. & Kern, was compared. In P. harknessii the mycelial cells giving rise to aecia were uninucleate. Young aeciospores were usually binucleate but most of them became uninucleate during maturation. Upon germination, nuclear division and septum formation occurred and germ tubes were divided into two, three, or four cells, each of which usually contained one nucleus. One to three side branches developed and nuclei migrated into them. Basidiospores were not produced. Despite the absence of basidiospores, P. harknessii is interpreted as having an endo-type life cycle with nuclear fusion and meiosis. In P. stalactiforme, aeciospores were binucleate and, upon germination, two nuclei migrated into the germ tube. The nuclei remained undivided during the formation of appressoria and infection pegs. Septa were not observed and branching was dichotomous or irregular.

Morphology and cytology of aeciospores and aeciospore germ tubes of host-alternating and pine-to-pine races of Cronartium flaccidum in northern Europe

1968 ◽  
Vol 46 (9) ◽  
pp. 1119-1122 ◽  
Author(s):  
Y. Hiratsuka
Keyword(s):  
Life Cycle ◽  
Pinus Sylvestris ◽  
Germ Tube ◽  
Nuclear Division ◽  
Nuclear Fusion ◽  
Northern Europe ◽  
Septum Formation ◽  
Germ Tubes ◽  
Irregular Growth

Host-alternating and pine-to-pine races of Cronartium flaccidum (Alb. & Schw.) Wint. (Peridermium pint Lév.) on Pinus sylvestris L. from northern Europe can be distinguished by differences in the morphology and cytology of aeciospores and aeciospore germ tubes. In the host alternating race, aeciospores were binucleate and, upon germination, two nuclei migrated into the germ tube. The nuclei remained undivided during migration. Septa were not observed and branching was dichotomous and irregular. Growth of germ tubes was indeterminate.In the pine-to-pine race, aeciospores were mostly binucleate but variable proportions (16% to 28%) were uninucleate. Upon germination nuclear division and septum formation occurred and the germ tubes were transformed into two, three, or four cells, each of which usually contained one nucleus. The germ tubes were straight and seldom exceeded 200 μ in length. One to three branches were observed. Despite the absence of basidiospores, the pine-to-pine race of C. flaccidum (= P. pini) is interpreted as having an endo-type life cycle with or without nuclear fusion and typical meiosis.

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.

Nuclear behavior and clarification of the spore stages of Uromyces koae

1981 ◽  
Vol 59 (5) ◽  
pp. 939-946 ◽  
Author(s):  
Donald E. Gardner
Keyword(s):  
Life Cycle ◽  
Meiotic Division ◽  
Germ Tube ◽  
Nuclear Staining ◽  
Diploid Nucleus ◽  
Spore Type ◽  
Acacia Koa ◽  
Nuclear Behavior ◽  
Germ Tubes

Recent observations showed that Uromyces koae Arthur in Stevens teliospores did not produce typical basidia or basidio-spores. The present study reveals that teliospores produced long germ tubes that are differentiated into wide proximal and narrow distal portions separated by a vesiclelike swelling. One or two extensive branches, each morphologically resembling the main tube, developed from individual germ tube cells. Nuclear staining revealed a single, presumably diploid nucleus in mature teliospores. One or more probable mitotic divisions in the main germ tube provided a diploid nucleus for each branch and for the main tube itself. Meiotic division of each nucleus produced a series of four smaller nuclei in the narrow portion of each branch and the main tube. The germ tubes may be modified basidia and serve as infectious hyphae in place of basidiospores.A formerly undescribed spore type associated with the teliospores is recognized as uredinial. This investigation shows that the life cycle of U. koae probably consists of four distinct stages, each on Acacia koa: the spermatial associated with the aecial on hypertrophied shoots, and the uredinial and telial together in discrete leaf pustules.

The role of primary germ tubes in the life cycle of Blumeria graminis: The primary germ tube is responsible for the suppression of resistance induction of a host plant cell

2007 ◽  
Vol 71 (4-6) ◽  
pp. 184-191 ◽  
Author(s):  
Naoto Yamaoka ◽  
Takayuki Ohta ◽  
Naoko Danno ◽  
Satoshi Taniguchi ◽  
Isao Matsumoto ◽  
...  
Keyword(s):  
Life Cycle ◽  
Host Plant ◽  
Plant Cell ◽  
Germ Tube ◽  
Blumeria Graminis ◽  
Resistance Induction ◽  
Germ Tubes

Anastomosis of germ tubes and migration of nuclei in germ tube networks of the soybean rust pathogen, Phakopsora pachyrhizi

2011 ◽  
Vol 132 (2) ◽  
pp. 163-167 ◽  
Author(s):  
R. Vittal ◽  
H. -C. Yang ◽  
G. L. Hartman
Keyword(s):  
Germ Tube ◽  
Soybean Rust ◽  
Phakopsora Pachyrhizi ◽  
Rust Pathogen ◽  
And Migration ◽  
Germ Tubes

scholarly journals I. Mahonia aquifolia as a nurse of the wheat mildew ( Puccinia graminis )

1883 ◽  
Vol 36 (228-231) ◽  
pp. 1-3
Keyword(s):  
Life Cycle ◽  
Puccinia Graminis ◽  
Knowing That ◽  
The Common ◽  
Germ Tubes

It has always been difficult to account for the widely-spread nature of outbreaks of wheat mildew in districts in which the common barberry is either entirely absent or very uncommon. In the year 1874 the Rev. James Stevenson found at Glamis, in Forfarshire, an Æcidium upon Mahonia aquifolia , which the Rev. M. J. Berkelev pronounced to be Æcidium berberidis . In the following year Dr. Paul Magnus found the same fungus at Lichterfelde, near Berlin, but since that time it does not seem to have been noticed by any one. On the 31st of May, 1883, Mr. William C. Little, of Stagsholt, March, gave me a freshly gathered specimen of Mahonia aquifolia , upon the berries of which the Æcidium was abundant. Knowing that upon the barberry no less than three different AEcidia occur, I determined to prove by direct experimental culture whether this one was the Æeidium berberidis of Persoon (the æcidiospore of Puccinia graminis ). At 10 p. m. on the evening of the 31st May I placed some of the spores upon the cuticle of some wheat-plants which had been cultivated under a bell-glass. In eleven days the uredo of Puccinia graminis made its appearance upon these plants. The details of this, as well as of two other experiments, are appended. On the 13th June I placed some of the secidiospores upon a piece of wheat cuticle; in twelve hours they had germinated, and a little later the germ-tubes were seen entering the stomata, in the same manner as those of Æcidium berberidis do (see figure). It is then clear that the Æcidium upon Mahonia aquifolia is identical with the Æcidium berberidis (Pers.), and is a part of the life-cycle of Puccinia graminis , and is unconnected with the Æcidium magellanicum (Berk.), and the Æcidium of Puccinia berberidis (Mont.). The Mahonia in question is widely cultivated in gardens throughout England and is a favourite evergreen in shrubberies. It is also extensively planted in woods as a covert for game.

Colletotrichum lindemuthianum exhibits different patterns of nuclear division at different stages in its vegetative life cycle

Mycologia ◽  
2013 ◽  
Vol 105 (4) ◽  
pp. 795-801 ◽  
Author(s):  
Francine H. Ishikawa ◽  
Elaine A. Souza ◽  
Nick D. Read ◽  
M. Gabriela Roca
Keyword(s):  
Life Cycle ◽  
Nuclear Division ◽  
Colletotrichum Lindemuthianum

Mitosis and nuclear degeneration: simultaneous events during secondary sporangia formation in Phytophthora palmivora

1973 ◽  
Vol 51 (9) ◽  
pp. 1673-1675 ◽  
Author(s):  
Don E. Hemmes ◽  
Hans R. Hohl
Keyword(s):  
Life Cycle ◽  
Nuclear Division ◽  
Phytophthora Palmivora ◽  
Nuclear Degeneration ◽  
Membranous Material

Somatic nuclear division is described for sporangia of Phytophthora palmivora. The division is intranuclear and involves centrioles and an eccentrically located spindle. The nucleolus persists throughout division. While these events take place, other nuclei within the same sporangium become surrounded by membranous material and degenerate by an autophagous process. The possible significance of these events for this stage of the life cycle is 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.

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