Genetic Studies on Selected Traits of<i>Nectria haematococca</i>

Tegtmeier, K. J.

doi:10.1094/phyto-77-604

Cited by 2 publications

(4 citation statements)

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“…The molecular mechanism of the Spore killer in Neurospora crassa is still a mystery. Plant pathogenic fungi, for example, Mycosphaerella graminicola (anamorph Septoria tritici ) and Nectria haematococca mating population VI (anamorph Fusarium solani ), generate ascospores containing “extra” chromosomes, termed “conditionally dispensable” chromosomes [ 7 - 11 ]. In the human fungal pathogen Cryptococcus neoformans , a large segmental duplication occurs during meiosis via telomere-telomere fusion and chromosomal translocation between two different chromosomes [ 12 , 13 ].…”

Section: Introductionmentioning

confidence: 99%

Trichoderma reesei meiosis generates segmentally aneuploid progeny with higher xylanase-producing capability

Chuang

Chen

et al. 2015

Biotechnol Biofuels

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BackgroundHypocrea jecorina is the sexual form of the industrial workhorse fungus Trichoderma reesei that secretes cellulases and hemicellulases to degrade lignocellulosic biomass into simple sugars, such as glucose and xylose. H. jecorina CBS999.97 is the only T. reesei wild isolate strain that is sexually competent in laboratory conditions. It undergoes a heterothallic reproductive cycle and generates CBS999.97(1-1) and CBS999.97(1-2) haploids with MAT1-1 and MAT1-2 mating-type loci, respectively. T. reesei QM6a and its derivatives (RUT-C30 and QM9414) all have a MAT1-2 mating type locus, but they are female sterile. Sexual crossing of CBS999.97(1-1) with either CBS999.97(1-2) or QM6a produces fruiting bodies containing asci with 16 linearly arranged ascospores (the sexual spores specific to ascomycetes). This sexual crossing approach has created new opportunities for these biotechnologically important fungi.ResultsThrough genetic and genomic analyses, we show that the 16 ascospores are generated via meiosis followed by two rounds of postmeiotic mitosis. We also found that the haploid genomes of CBS999.97(1-2) and QM6a are similar to that of the ancestral T. reesei strain, whereas the CBS999.97(1-1) haploid genome contains a reciprocal arrangement between two scaffolds of the CBS999.97(1-2) genome. Due to sequence heterozygosity, most 16-spore asci (>90%) contain four or eight inviable ascospores and an equal number of segmentally aneuploid (SAN) ascospores. The viable SAN progeny produced higher levels of xylanases and white conidia due to segmental duplication and deletion, respectively. Moreover, they readily lost the duplicated segment approximately two weeks after germination. With better lignocellulosic biomass degradation capability, these SAN progeny gain adaptive advantages to the natural environment, especially in the early phase of colonization.ConclusionsOur results have not only further elucidated T. reesei evolution and sexual development, but also provided new perspectives for improving T. reesei industrial strains.Electronic supplementary materialThe online version of this article (doi:10.1186/s13068-015-0202-6) contains supplementary material, which is available to authorized users.

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Section: Introductionmentioning

confidence: 99%

Trichoderma reesei meiosis generates segmentally aneuploid progeny with higher xylanase-producing capability

Chuang

Chen

et al. 2015

Biotechnol Biofuels

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“…The significance of the observed maternal influence is presently unclear, as other crosses (described below) did not appear to share this feature. Irregular meiotic transmission of Pda genes has been noted previously, but its cause was unknown (la, 7, 9, 9a, 10a, 16,17). In principle, excess null phenotypes could arise as a result of epistatic suppression by a modifying gene.…”

Section: Resultsmentioning

confidence: 88%

“…The techniques used for culture maintenance on V8 Juice agar, performing crosses, and ascospore isolation are described in detail elsewhere (16). In general, the mycelium of the female parent is grown for 7 to 10 days and then fertilized by a conidial suspension of a male parent.…”

Section: Materuils and Methodsmentioning

confidence: 99%

“…Mating type (Mat) was determined by crosses to reference strains (20). Mat consistently segregates as two alleles at a single locus, Mat, and was used to verify that all meiotic products were represented in a tetrad (16). A diffusible bluish-black pigment whose production was probably not under simple genetic control was occasionally used to identify ascospore twins within a tetrad.…”

Section: Materuils and Methodsmentioning

confidence: 99%

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Three Genes for Metabolism of the Phytoalexin Maackiain in the Plant Pathogen Nectria haematococca : Meiotic Instability and Relationship to a New Gene for Pisatin Demethylase

Miao

VanEtten

1992

Appl Environ Microbiol

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Some isolates of the plant-pathogenic fungus Nectria haematococca mating population (MP) VI metabolize maackiain and medicarpin, two antimicrobial compounds (phytoalexins) synthesized by chickpea (Cicer arietinum L.). The enzymatic modifications by the fungus convert the phytoalexins to less toxic derivatives, and this detoxification has been proposed to be important for pathogenesis on chickpea. In the present study, loci controlling maackiain metabolism (Mak genes) were identified by crosses among isolates of N. haematococca MP VI that differed in their ability to metabolize the phytoalexin. Strains carrying Maki or Mak2 converted maackiain to la-hydroxymaackiain, while those with Mak3 converted it to 6a-hydroxymaackiain. Maki and Mak2 were unusual in that they often failed to be inherited by progeny. Maki was closely linked to Pda6, a new member in a family of genes in N. haematococca MP VI that encode enzymes for detoxification of pisatin, the phytoalexin synthesized by garden pea. Like Maki, Pda6 was also transmitted irregularly to progeny. Although the unusual meiotic behaviors of some Mak genes complicate genetic analysis, identification of these genes should afford a more thorough evaluation of the role of phytoalexin detoxification in the pathogenesis of N. haematococca MP VI on chickpea.

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Genetic Studies on Selected Traits ofNectria haematococca

Cited by 2 publications

References 0 publications

Trichoderma reesei meiosis generates segmentally aneuploid progeny with higher xylanase-producing capability

Trichoderma reesei meiosis generates segmentally aneuploid progeny with higher xylanase-producing capability

Three Genes for Metabolism of the Phytoalexin Maackiain in the Plant Pathogen Nectria haematococca : Meiotic Instability and Relationship to a New Gene for Pisatin Demethylase

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