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Mitochondrial Transcription of Entomopathogenic Fungi Reveals Evolutionary Aspects of Mitogenomes

Entomopathogenic fungi and more specifically genera Beauveria and Metarhizium have been exploited for the biological control of pests. Genome analyses are important to understand better their mode of action and thus, improve their efficacy against their hosts. Until now, the sequences of their mitoc...

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Autores principales: Varassas, Stylianos P., Kouvelis, Vassili N.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Frontiers Media S.A. 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8979003/
https://www.ncbi.nlm.nih.gov/pubmed/35387072
http://dx.doi.org/10.3389/fmicb.2022.821638
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author Varassas, Stylianos P.
Kouvelis, Vassili N.
author_facet Varassas, Stylianos P.
Kouvelis, Vassili N.
author_sort Varassas, Stylianos P.
collection PubMed
description Entomopathogenic fungi and more specifically genera Beauveria and Metarhizium have been exploited for the biological control of pests. Genome analyses are important to understand better their mode of action and thus, improve their efficacy against their hosts. Until now, the sequences of their mitochondrial genomes were studied, but not at the level of transcription. Except of yeasts and Neurospora crassa, whose mt gene transcription is well described, in all other Ascomycota, i.e., Pezizomycotina, related information is extremely scarce. In this work, mt transcription and key enzymes of this function were studied. RT-PCR experiments and Northern hybridizations reveal the transcriptional map of the mt genomes of B. bassiana and M. brunneum species. The mt genes are transcribed in six main transcripts and undergo post-transcriptional modifications to create single gene transcripts. Promoters were determined in both mt genomes with a comparative in silico analysis, including all known information from other fungal mt genomes. The promoter consensus sequence is 5′-ATAGTTATTAT-3′ which is in accordance with the definition of the polycistronic transcripts determined with the experiments described above. Moreover, 5′-RACE experiments in the case of premature polycistronic transcript nad1-nad4-atp8-atp6 revealed the 5′ end of the RNA transcript immediately after the in silico determined promoter, as also found in other fungal species. Since several conserved elements were retrieved from these analyses compared to the already known data from yeasts and N. crassa, the phylogenetic analyses of mt RNA polymerase (Rpo41) and its transcriptional factor (Mtf1) were performed in order to define their evolution. As expected, it was found that fungal Rpo41 originate from the respective polymerase of T7/T3 phages, while the ancestor of Mtf1 is of alpha-proteobacterial origin. Therefore, this study presents insights about the fidelity of the mt single-subunit phage-like RNA polymerase during transcription, since the correct identification of mt promoters from Rpo41 requires an ortholog to bacterial sigma factor, i.e., Mtf1. Thus, a previously proposed hypothesis of a phage infected alpha-proteobacterium as the endosymbiotic progenitor of mitochondrion is confirmed in this study and further upgraded by the co-evolution of the bacterial (Mtf1) and viral (Rpo41) originated components in one functional unit.
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spelling pubmed-89790032022-04-05 Mitochondrial Transcription of Entomopathogenic Fungi Reveals Evolutionary Aspects of Mitogenomes Varassas, Stylianos P. Kouvelis, Vassili N. Front Microbiol Microbiology Entomopathogenic fungi and more specifically genera Beauveria and Metarhizium have been exploited for the biological control of pests. Genome analyses are important to understand better their mode of action and thus, improve their efficacy against their hosts. Until now, the sequences of their mitochondrial genomes were studied, but not at the level of transcription. Except of yeasts and Neurospora crassa, whose mt gene transcription is well described, in all other Ascomycota, i.e., Pezizomycotina, related information is extremely scarce. In this work, mt transcription and key enzymes of this function were studied. RT-PCR experiments and Northern hybridizations reveal the transcriptional map of the mt genomes of B. bassiana and M. brunneum species. The mt genes are transcribed in six main transcripts and undergo post-transcriptional modifications to create single gene transcripts. Promoters were determined in both mt genomes with a comparative in silico analysis, including all known information from other fungal mt genomes. The promoter consensus sequence is 5′-ATAGTTATTAT-3′ which is in accordance with the definition of the polycistronic transcripts determined with the experiments described above. Moreover, 5′-RACE experiments in the case of premature polycistronic transcript nad1-nad4-atp8-atp6 revealed the 5′ end of the RNA transcript immediately after the in silico determined promoter, as also found in other fungal species. Since several conserved elements were retrieved from these analyses compared to the already known data from yeasts and N. crassa, the phylogenetic analyses of mt RNA polymerase (Rpo41) and its transcriptional factor (Mtf1) were performed in order to define their evolution. As expected, it was found that fungal Rpo41 originate from the respective polymerase of T7/T3 phages, while the ancestor of Mtf1 is of alpha-proteobacterial origin. Therefore, this study presents insights about the fidelity of the mt single-subunit phage-like RNA polymerase during transcription, since the correct identification of mt promoters from Rpo41 requires an ortholog to bacterial sigma factor, i.e., Mtf1. Thus, a previously proposed hypothesis of a phage infected alpha-proteobacterium as the endosymbiotic progenitor of mitochondrion is confirmed in this study and further upgraded by the co-evolution of the bacterial (Mtf1) and viral (Rpo41) originated components in one functional unit. Frontiers Media S.A. 2022-03-21 /pmc/articles/PMC8979003/ /pubmed/35387072 http://dx.doi.org/10.3389/fmicb.2022.821638 Text en Copyright © 2022 Varassas and Kouvelis. https://creativecommons.org/licenses/by/4.0/This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
spellingShingle Microbiology
Varassas, Stylianos P.
Kouvelis, Vassili N.
Mitochondrial Transcription of Entomopathogenic Fungi Reveals Evolutionary Aspects of Mitogenomes
title Mitochondrial Transcription of Entomopathogenic Fungi Reveals Evolutionary Aspects of Mitogenomes
title_full Mitochondrial Transcription of Entomopathogenic Fungi Reveals Evolutionary Aspects of Mitogenomes
title_fullStr Mitochondrial Transcription of Entomopathogenic Fungi Reveals Evolutionary Aspects of Mitogenomes
title_full_unstemmed Mitochondrial Transcription of Entomopathogenic Fungi Reveals Evolutionary Aspects of Mitogenomes
title_short Mitochondrial Transcription of Entomopathogenic Fungi Reveals Evolutionary Aspects of Mitogenomes
title_sort mitochondrial transcription of entomopathogenic fungi reveals evolutionary aspects of mitogenomes
topic Microbiology
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8979003/
https://www.ncbi.nlm.nih.gov/pubmed/35387072
http://dx.doi.org/10.3389/fmicb.2022.821638
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