GELASINOSPORA, A NEW GENUS OF PYRENOMYCETES WITH PITTED SPORES

Dowding, Eleanor Silver

doi:10.1139/cjr33-087

Cited by 53 publications

(18 citation statements)

References 2 publications

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“…Dowding (1933) has reported that some spores of G. cerealis produce but one vesicle; this was not observed in any of our cultures.…”

Section: Methodscontrasting

confidence: 54%

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A Cytotaxonomic Study of Three Species of Gelasinospora

Sun¹,

Alexopoulos²,

Wilson

1954

CYTOLOGIA

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“…Dowding (1933) has reported that some spores of G. cerealis produce but one vesicle; this was not observed in any of our cultures.…”

Section: Methodscontrasting

confidence: 54%

“…Gelasinospora, a genus of pyrenomycetes closely allied to Ne urospora and Fimetaria, was erected by Dowding (1933) on the basis of her studies on G. cerealis and G. tetraspernra, to include those two species.…”

Section: Introductionmentioning

confidence: 99%

A Cytotaxonomic Study of Three Species of Gelasinospora

Sun¹,

Alexopoulos²,

Wilson

1954

CYTOLOGIA

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“…Nothing is known genetically about G. tetrasperma beyond the fact that ascospores from its four-spored asci must be heterokaryotic for mating type, because [Dowding, 1933;Dodge, 1937, Campbell, 19371.…”

Section: Ascus Development In Gelasirwspora Tetraspermamentioning

confidence: 99%

Diverse programs of ascus development in pseudohomothallic species of Neurospora, Gelasinospora, and Podospora

Raju¹,

Perkins²

1994

Dev. Genet.

112

106

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Meiosis and ascospore development in the four-spored pseudohomothallic ascomycetes Neurospora tetrasperma, Gelasinospora tetrasperma, Podospora anserina, and P. tetraspora have been reexamined, highlighting differences that reflect independent origins of the four-spored condition in the different genera. In these species, as in the heterothallic eight-spored N. crassa, fusion of haploid nuclei is followed directly by meiosis and a postmeiotic mitosis. These divisions take place within a single unpartitioned giant cell, the ascus, which attains a length of > 0.1 mm before nuclei are enclosed by ascospore walls. Two basically different modes underlie the delivery of opposite mating type nuclei into each of the four ascospores in the different genera. In N. tetrasperma on the one hand, the mating type locus is closely centromere-linked. Mating types therefore segregate at the first meiotic division. The second-division spindles of N. tetrasperma overlap and are usually parallel to one another, in contrast to the their tandem arrangement in N. crassa. As a result, nonsister nuclei of opposite mating type are placed close together in each half-ascus and a pair is enclosed in each ascospore. In the Podospora and Gelasinospora species on the other hand, the second-division spindles are in tandem, with sister nuclei of opposite mating type associated as a pair in each half-ascus. It is established for P. anserina and inferred for P. tetraspora and G. tetrasperma that a single reciprocal crossing over almost always occurs in the mating type-centromere interval, ensuring that mating types segregate at the second meiotic division and that nuclei of opposite mating type are enclosed in each ascospore. Other differences are also seen that are less fundamental. Neurospora tetrasperma differs from the other species in the orientation of chromosomes and spindle pole body plaques at interphase II. Third-division spindles are oriented parallel to the ascus wall in Gelasinospora but across the ascus in Podospora and Neurospora. The two Podospora species differ from one another in nuclear behavior following mitosis in the young ascospores. In P. tetraspora, two of the four nuclei migrate into the tail cell, which degenerates, leaving one functional nucleus of each mating type. In P. anserina, by contrast, only one of the four nuclei moves into the tail cell, leaving the germinating ascospore with two functional nuclei of one mating type and one of the other. The pseudohomothallic condition with its heterokaryotic vegetative phase has significant consequences for both the individual organism and the breeding system. Genetic controls of development and recombination are complex.(ABSTRACT TRUNCATED AT 400 WORDS)

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“…The genera placed within this family mainly are differentiated by ascospore morphology and ornamentation. For instance, the genera Neurospora Shear & Dodge (1927) and Gelasinospora Dowding (1933) are morphologically comparable except the former produces ascospores with elevated longitudinal ridges (ribs) separated by depressed grooves (veins), and the latter produces ascospores with spherical or oval indentations (pits). Within these two genera, the patterns of ascospore ornamentation can vary significantly, and significant overlap may occur in morphological traits that are used to distinguish species.…”

Section: Introductionmentioning

confidence: 99%