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General scheme of trisporic acid synthesis in zygomycetes (simplified). The biosynthesis of trisporic acid depends on cooperative action of complementary mating types or on compatible partners in the host/parasite system Absidia glauca/Parasitella parasitica. The (+)specific volatile compound 4-dihydromethyltrisporate is passed on to the (-)-mating type, whereas the (-)-specific compound trisporin is further processed by the (+)-type. Both mating partners are able to process these substances to trisporic acid. Oxidations in (-)-strains are catalysed by dehydrogenases, whereas (+)-strains are assumed to use oxidases.
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The zygomycete Parasitella parasitica is a facultative fusion parasite of many but not all mucoralean fungi. In model experiments with one of the natural hosts, Absidia glauca, the propagation success of the host is reduced not more than approximately 40% at the level of sporangiospore formation, but growth of the parasite is increased considerably...
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Citations
... Later, the term fusion parasitism has been coined for such systems, which occur also between several other mucoralen fungi (Jeffries and Young 1994). The system, also with respect to the physiology of partner recognition, has been discussed in detail (Wo stemeyer et al. 2016). ...
... The transfer of coding DNA from P. parasitica to A. glauca has been studied in some detail via complementation of auxotrophic mutants (Kellner et al. 1993;Wo stemeyer et al. 1995;Burmester et al. 2013;Wo stemeyer et al. 2016). These events are experimentally selected for and, although they occur in the percentage range, are principally suited to detect even rare frequencies. ...
The mucoralean zygomycete Parasitella parasitica infects complementary mating types of its host Absidia glauca. This parasitism is characterized by fusion between the partners at infection sites. As a consequence, nuclei of the parasite invade into the host's mycelium. Both types of nuclei undergo frequent recombination. Apart from complementing auxotrophies of the host by genes from the parasite, especially repetitive DNA elements exert remarkable effects in recombinants. Parasitella-specific sequences are efficiently transferred and established in A. glauca, sometimes in copy numbers, exceeding the situation in the donor. In addition, at least one frequent Absidia-specific element (rAg1), lacking from the Parasitella genome, is considerably affected by infection. We have sequenced the genomes of both, host and parasite, and confirmed that the genomes are constituted by 32% (Absidia) and 22% (Parasitella) repetitive DNA. Many of these elements were attributed to known repeat families, some of which are reported as transposable, but approximately 1/3 of all elements are specific for these organisms. Interestingly, both fungi present different repeat specificities. DIRS elements as well as Ginger, MuLE-F, TcMar-ISRm11, TcMar-Tc1, LINE/Jockey and LINE/R1 are specific for the Parasitella parasitica. Transposable elements from the group of endogenous retroviroses as well as LINE/RTE-BovB and Merlin occur exclusively in Absidia glauca. Endocytobiosis and Cell Research (2022) 31:23-28 Category: Research article
... Curiously, this gene with unknown function contains a signal peptide and a chromatin associated FoP domain, which results controversial for a glycosylated-secreted protein. It displays close homology to A. glauca and P. parasitica sequences, both symbiotic Mucorales with reported horizontal gene transfer events [28]. Specifically, A. glauca contains two different proteins and each one displays exclusive homology to N-terminal and to C-terminal regions of M. circinelloides sequence, respectively. ...
The increasing number of infections by species of Mucorales and their high mortality constitute an important concern for public health. This study aims to decipher the genetic basis of Mucor circinelloides pathogenicity, which displays virulence in a strain dependent manner. Assuming that genetic differences between strains may be linked to different pathotypes, we have conducted a study to explore genes responsible for virulence in M. circinelloides by whole genome sequencing of the avirulent strain NRRL3631 and comparison with the virulent strain CBS277.49. This genome analysis revealed 773 truncated, discontiguous and absent genes in the NRRL3631 strain. We also examined phenotypic traits resulting in reduced heat stress tolerance, chitosan content and lower susceptibility to toxic compounds (calcofluor white and sodium dodecyl sulphate) in the virulent strain, suggesting the influence of cell wall on pathogenesis. Based on these results, we focused on studying extracellular protein-coding genes by gene deletion and further pathotype characterization of mutants in murine models of pulmonary and systemic infection. Deletion of gene ID112092, which codes for a hypothetical extracellular protein of unknown function, resulted in significant reduction of virulence.
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... However, nearly two decades ago, Wöstemeyer et al. [56] hypothesized that hyphal fusion mycoparasitism might offer nearly ideal conditions for interfungal DNA exchanges. They demonstrated the transfer of genes in vitro from the Mucoromycotina mycoparasite Parasitella parasitica to its Mucoromycotina host, Absidia glauca [75]. Our discovery that a massive but taxonomically restricted putative LGT of pcwdCAZymes occurred in Trichoderma from filamentous Ascomycota hosts correlates with the expansion of Trichoderma mycoparasitic host range to Ascomycota. ...
Unlike most other fungi, molds of the genus Trichoderma (Hypocreales, Ascomycota) are aggressive parasites of other fungi and efficient decomposers of plant biomass. Although nutritional shifts are common among hypocrealean fungi, there are no examples of such broad substrate versatility as that observed in Trichoderma. A phylogenomic analysis of 23 hypocrealean fungi (including nine Trichoderma spp. and the related Escovopsis weberi) revealed that the genus Trichoderma has evolved from an ancestor with limited cellulolytic capability that fed on either fungi or arthropods. The evolutionary analysis of Trichoderma genes encoding plant cell wall-degrading carbohydrate-active enzymes and auxiliary proteins (pcwdCAZome, 122 gene families) based on a gene tree / species tree reconciliation demonstrated that the formation of the genus was accompanied by an unprecedented extent of lateral gene transfer (LGT). Nearly one-half of the genes in Trichoderma pcwdCAZome (47%) were obtained via LGT from plant-associated filamentous fungi belonging to different classes of Ascomycota, while no LGT was observed from other potential donors. In addition to the ability to feed on unrelated fungi (such as Basidiomycota), we also showed that Trichoderma is capable of endoparasitism on a broad range of Ascomycota, including extant LGT donors. This phenomenon was not observed in E. weberi and rarely in other mycoparasitic hypocrealean fungi. Thus, our study suggests that LGT is linked to the ability of Trichoderma to parasitize taxonomically related fungi (up to adelphoparasitism in strict sense). This may have allowed primarily mycotrophic Trichoderma fungi to evolve into decomposers of plant biomass.
Fungicolous fungi are a very large, diverse, ecological and trophic group of organisms that are associated with other fungi. This association occurs with species of different lineages across the fungal kingdom. They are recognized as symbionts, mycoparasites, saprotrophs, and even neutrals. Wherever fungi have been found, fungicolous taxa have also been found. Homogeneous environments favour the development of highly adapted and coevolved fungicolous species, which could have led to host-specificity aspects. As a primary consumer, fungicolous fungi decrease the turnaround time of certain nutrients in food webs, due to their special often-rapid life cycles. They may also significantly affect population dynamics and population sizes of their hosts in aquatic or terrestrial ecosystems. As mycoparasites of pathogenic fungi, some fungicolous fungi have been explored as biocontrol agents. They may also cause serious diseases of cultivated edible and medicinal mushrooms, decreasing both yield and quality. Fungicolous fungi could be used as model organisms that may help determine better understanding of species interactions, fungal evolution and divergence, and fungicolous mechanisms. This review summarizes our current understanding of fungicolous fungi, with a particular focus on the terminology, diversity, global distribution, and interaction with their hosts. We also provide a checklist including 1552 fungicolous fungal taxa so far recorded following the updated classification schemes. There is a need for further investigations on this ecologically important group of fungi to better understand their biology, ecological aspects, origin and divergence, host-specificity and application in biocontrol. Accurate identification of these fungi as pathogens and their significance in quarantine purposes on the mushroom industry need further evaluations so that efficient control measures can be developed for better disease management purposes.
