Intraspecific hybridisation of Trichoderma pseudokoningii by anastomosis and by protoplast fusion

Furlaneto, Márcia Cristina; Pizzirani-Kleiner, Aline Aparecida

doi:10.1016/0378-1097(92)90627-z

Cited by 8 publications

(12 citation statements)

References 17 publications

(6 reference statements)

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“…Unstable recombinants, which changed preferentially to one of the parental types, were also detected. In all original colonies analyzed, except one, parental types always were detected besides the recombinants, indicating a strong heterokaryotic condition in this organism, which produces uninucleate and also a lower frequency of 0.1% of binucleate conidia (Furlaneto and Pizzirani-Kleiner 1992). This situation makes it difficult to estimate recombinant occurrence frequencies, unless strains with good genetic markers are used and careful single spore colony recovery of possible recombinants is performed.…”

mentioning

confidence: 98%

“…Heterokaryons were carried out between two previously obtained strains (Furlaneto and Pizzirani-Kleiner 1992), carrying morphologic and auxotrophic complementary genetic markers (whi4 leu1 thsl + ylo5 rib1 arg2), using liquid minimal medium (MM) with 2% complete medium (CM) and then cultivated on solid MM (Roper 1952), at 28°C. Conidial suspensions from ab + cd heterokaryons (symbolized here by the auxotrophic markers ), which assumed a green wild-type color, were plated onto CM (10'-lo2 conidia/plate) to estimate the total number of viable conidia and the parental ratio.…”

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confidence: 99%

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Genetic recombinants inTrichoderma pseudokoningii(Rifai) without typical parasexuality

Bagagli¹,

Furlaneto²,

Pizzirani-Kleiner³

et al. 1995

Can. J. Microbiol.

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Heterokaryons were obtained by hyphal anastomosis in Trichoderma pseudokoningii using strains with morphologic and double auxotrophic genetic markers. Stable haploid and unstable hyperhaploid recombinants were detected in monosporic colonies derived from heterokaryons and selected in appropriate media or by an enrichment filtration technique. Diploids were not observed and the recombinant frequencies were higher than those found in fungi with a typical parasexual cycle. The mechanism of recombinant emergence may involve a transient diploid formation followed by chromosomal losses at the hyphal stages, resulting in haploid and hyperhaploid recombinants. The possibility of intrachromosomal rearrangement with the involvement of cytoplasmatic DNA as a heterokaryotic transformation system cannot be excluded.RCsume : Des hCtCrocaryons ont Ct C obtenus par anastomose d'hyphes dans Trichoderma pseudokoningii en utilisant des souches possCdant des marqueurs gCnCtiques de la morphologie et de l'auxotrophie. Des recombinants haploides stables et hyperhaploldes instables ont Ct C dCtectts dans des colonies monosporiques dCrivCes d7hCt6rocaryons et sClectionnCs soit dans un milieu de culture approprit ou par une technique d'enrichissement par filtration. Des diploides n'ont pas Ct C observts et les frequences de recombinaison Ctaient plus ClevCes que celles observCes chez les champignons avec un cycle typique parasexuel. Le mecanisme de 1'Cmergence d'un recombinant peut impliquer une formation diplo'ide transitoire suivie par des pertes chromosomiques aux stades de formation des hyphes, qui rCsulte en la production de recombinants haploldes et hyperploides. La possibilitC de rCarrangement intrachromosomique avec l'implication d'ADN cytoplasmique en tant que syst2me de transformation hCtCrocaryotique ne peut &re exclue.

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mentioning

confidence: 98%

mentioning

confidence: 99%

Genetic recombinants inTrichoderma pseudokoningii(Rifai) without typical parasexuality

Bagagli¹,

Furlaneto²,

Pizzirani-Kleiner³

et al. 1995

Can. J. Microbiol.

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“…Stasz et al (50) described the occurrence of multinucleated conidia in strains of Trichoderma harzianum and Furlaneto & Pizzirani-Kleiner (23) observed that recombinant prototroph strains of T. pseudokoningii , obtained from crosses via protoplast fusion had binucleated conidia.…”

Section: Resultsmentioning

confidence: 99%

“…Whithin the Trichoderma genus there are descriptions of obtention of recombinants directly from the heterokaryon between strains of several species, which were formed by means of hyphal anastomosis, protoplast fusion or nuclear transfers (3, 7, 23, 37, 38, 46, 47, 48, 49, 50). In several experiments with Trichoderma , the occurrence of characteristic patterns has been observed and would be related to some level of vegetative incompatibility or due to limited vegetative compatibility (5, 46, 48, 49).…”

Section: Introductionmentioning

confidence: 99%

“…There are some reports of the obtention of recombinant progeny of T. pseudokoningii directly from the heterokaryon, by hyphal anastomosis or protoplast fusion, in which almost all progeny strains showed the auxotrophic markers from only one of the parents (3, 7, 23). As described by Stasz & Harman (48), the same pattern of recombinant progeny strains is frequently obtained from heterokaryons in several crosses between T. pseudokoningii contrasting strains (3, 7).…”

Section: Introductionmentioning

confidence: 99%

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Limited vegetative compatibility as a cause of somatic recombination in Trichoderma pseudokoningii

Barcellos¹,

Hungría²,

Pizzirani-Kleiner³

2011

Braz. J. Microbiol.

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With the aim of a better characterization of the somatic recombination process in Trichoderma pseudokoningii, a progeny from crossings between T. pseudokoningii strains contrasting for auxotroph markers was characterized by RAPD markers and PFGE (electrophoretic karyotype). Cytological studies of the conidia, conidiogenesis and heterokaryotic colonies were also performed. The genotypes of the majority of the recombinant strains analyzed were similar to only one of the parental strains and the low frequency of polymorphic RAPD bands suggested that the nuclear fusions may not occur into the heterokaryon. In some heterokaryotic regions the existence of intensely staining hyphae might be related to cell death. We proposed that a mechanism of somatic recombination other than parasexuality might occur, being related to limited vegetative compatibility after postfusion events, as described for other Trichoderma species.

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Alternative reproduction pathway inAspergillus nidulans

2003

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Recombinant haploid segregants were recovered in filamentous fungus Aspergillus nidulans (Eidam) G. Winter directly from the heterokaryons instead of diploid segregants (process described earlier as parameiosis). In spite of the reproductive complexity of A. nidulans, parameiosis has only now been observed in this fungus. Since parameiosis was characterized by the occurrence of genetic recombination inside heterokaryotic hyphae, master strains (uvs+) and uvs mutants with high rate of both mitotic exchanges or chromosome nondisjunction were used to form heterokaryons. Two groups of mitotic segregants were recovered directly from heterokaryons--aneuploids and stable haploids. Heterokaryons formed with uvs mutants produced a higher number of parameiotic segregants compared to the heterokaryons formed with uvs+ strains. Segregants were analyzed by nutritional markers, acriflavine resistance and conidial color. Normal meiotic behavior of haploid recombinants was observed.

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Intraspecific hybridisation of Trichoderma pseudokoningii by anastomosis and by protoplast fusion

Cited by 8 publications

References 17 publications

Genetic recombinants inTrichoderma pseudokoningii(Rifai) without typical parasexuality

Genetic recombinants inTrichoderma pseudokoningii(Rifai) without typical parasexuality

Limited vegetative compatibility as a cause of somatic recombination in Trichoderma pseudokoningii

Alternative reproduction pathway inAspergillus nidulans

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