scholarly journals Genus level analysis of PKS-NRPS and NRPS-PKS hybrids reveals their origin in Aspergilli

BMC Genomics ◽  
2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Sebastian Theobald ◽  
Tammi C. Vesth ◽  
Mikael R. Andersen

Abstract Background Filamentous fungi produce a vast amount of bioactive secondary metabolites (SMs) synthesized by e.g. hybrid polyketide synthase-nonribosomal peptide synthetase enzymes (PKS-NRPS; NRPS-PKS). While their domain structure suggests a common ancestor with other SM proteins, their evolutionary origin and dynamics in fungi are still unclear. Recent rational engineering approaches highlighted the possibility to reassemble hybrids into chimeras — suggesting molecular recombination as diversifying mechanism. Results Phylogenetic analysis of hybrids in 37 species – spanning 9 sections of Aspergillus and Penicillium chrysogenum – let us describe their dynamics throughout the genus Aspergillus. The tree topology indicates that three groups of PKS-NRPS as well as one group of NRPS-PKS hybrids developed independently from each other. Comparison to other SM genes lead to the conclusion that hybrids in Aspergilli have several PKS ancestors; in contrast, hybrids are monophyletic when compared to available NRPS genes — with the exception of a small group of NRPSs. Our analysis also revealed that certain NRPS-likes are derived from NRPSs, suggesting that the NRPS/NRPS-like relationship is dynamic and proteins can diverge from one function to another. An extended phylogenetic analysis including bacterial and fungal taxa revealed multiple ancestors of hybrids. Homologous hybrids are present in all sections which suggests frequent horizontal gene transfer between genera and a finite number of hybrids in fungi. Conclusion Phylogenetic distances between hybrids provide us with evidence for their evolution: Large inter-group distances indicate multiple independent events leading to the generation of hybrids, while short intra-group distances of hybrids from different taxonomic sections indicate frequent horizontal gene transfer. Our results are further supported by adding bacterial and fungal genera. Presence of related hybrid genes in all Ascomycetes suggests a frequent horizontal gene transfer between genera and a finite diversity of hybrids — also explaining their scarcity. The provided insights into relations of hybrids and other SM genes will serve in rational design of new hybrid enzymes.

mBio ◽  
2021 ◽  
Vol 12 (2) ◽  
Author(s):  
Ahmed M. Moustafa ◽  
Senthil Kumar Velusamy ◽  
Lidiya Denu ◽  
Apurva Narechania ◽  
Daniel H. Fine ◽  
...  

ABSTRACT Like the bacterial residents of the human gut, it is likely that many of the species in the human oral microbiota have evolved to better occupy and persist in their niche. Aggregatibacter actinomycetemcomitans (Aa) is both a common colonizer of the oral cavity and has been implicated in the pathogenesis of periodontal disease. Here, we present a whole-genome phylogenetic analysis of Aa isolates from humans and nonhuman primates that revealed an ancient origin for this species and a long history of association with the Catarrhini, the lineage that includes Old World monkeys (OWM) and humans. Further genomic analysis showed a strong association with the presence of a short-chain fatty acid (SCFA) catabolism locus (atoRDAEB) in many human isolates that was absent in almost all nonhuman OWM isolates. We show that this locus was likely acquired through horizontal gene transfer. When grown under conditions that are similar to those at the subgingival site of periodontitis (anaerobic, SCFA replete), Aa strains with atoRDAEB formed robust biofilms and showed upregulation of genes involved in virulence, colonization, and immune evasion. Both an isogenic deletion mutant and nonhuman primate isolates lacking the ato locus failed to grow in a robust biofilm under these conditions, but grew well under the carbohydrate-rich conditions similar to those found above the gumline. We propose that the acquisition of the ato locus was a key evolutionary step allowing Aa to utilize SCFAs, adapt, and modulate subgingival disease. IMPORTANCE There has been considerable interest in the impact of short-chain fatty acids (SCFAs) on inflammatory effects related to the microbiome. Here, we present evidence that SCFAs may also be important in disease by providing an energy source or disease-associated cue for colonizing pathogens. We propose that SCFAs allow Aggregatibacter actinomycetemcomitans (Aa) to adapt to the subgingival anaerobic environment, which is the site of human periodontitis. Under anaerobic, SCFA-rich conditions, human-derived Aa strains that possess butyrate metabolism genes form strong biofilms and upregulate virulence genes. Our phylogenetic analysis highlights a long history of evolution of Aa with its primate hosts and suggests that the acquisition of butyrate metabolism genes may have been a critical step in allowing Aa to colonize a new niche and cause disease in humans. Overall, this study highlights the important role that horizontal gene transfer may play in microbial adaptation and the evolution of infectious disease.


Author(s):  
M. E. Vladimirova ◽  
V. S. Muntyan ◽  
A. S. Saksaganskaya ◽  
B. V. Simarov ◽  
M. L. Roumiantseva

Genomic islands of closely related S. meliloti and S. medicae species were evaluated and homologous sequences were identified; it has been suggested that horizontal gene transfer occurs at homologous tRNA sites.


2020 ◽  
Author(s):  
Matthew A. Spence ◽  
Matthew D. Mortimer ◽  
Ashley M. Buckle ◽  
Bui Quang Minh ◽  
Colin J. Jackson

Serine protease inhibitors (serpins) are found in all kingdoms of life and play essential roles in multiple physiological processes. Owing to the diversity of the superfamily, phylogenetic analysis is challenging and prokaryotic serpins have been speculated to have been acquired from Metazoa through horizontal gene transfer (HGT) due to their unexpectedly high homology. Here we have leveraged a structural alignment of diverse serpins to generate a comprehensive 6000-sequence phylogeny that encompasses serpins from all kingdoms of life. We show that in addition to a central “hub” of highly conserved serpins, there has been extensive diversification of the superfamily into many novel functional clades. Our analysis indicates that the hub proteins are ancient and are similar because of convergent evolution, rather than the alternative hypothesis of HGT. This work clarifies longstanding questions in the evolution of serpins and provides new directions for research in the field of serpin biology.


2020 ◽  
Author(s):  
Zhengmi He ◽  
Pan Long ◽  
Fang Fang ◽  
Sainan Li ◽  
Ping Zhang ◽  
...  

Abstract Background: Amanitin-producing mushrooms, mainly distributed in the genera Amanita , Galerina and Lepiota , possess MSDIN gene family for the biosynthesis of many cyclopeptides catalysed by prolyl oligopeptidase (POP). Recently, transcriptome sequencing has proven to be an efficient way to mine MSDIN and POP genes in these lethal mushrooms. Thus far, only A . palloides and A. bisporigera from North America and A . exitialis and A. rimosa from Asia have been studied based on transcriptome analysis. However, the MSDIN and POP genes of many amanitin-producing mushrooms in China remain unstudied; hence, the transcriptomes of these speices deserve to be analysed. Results: In this study, the MSDIN and POP genes from ten Amanita species, two Galerina species and Lepiota venenata were studied and the phylogenetic relationships of their MSDIN and POP genes were analysed. Through transcriptome sequencing and PCR cloning, 19 POP genes and 151 MSDIN gened to encode 98 non-duplicated cyclopeptides, including α- amanitin, β-amanitin, phallacidin, phalloidin and 94 unknown peptides, were found in these species. Phylogenetic analysis showed that (1) MSDIN genes generally clustered depending on the taxonomy of the genus, while Amanita MSDIN genes clustered depending on the chemical substance; and (2) the POPA genes of Amanita , Galerina and Lepiota clustered and were separated into three different groups, but the POPB genes of the three distinct genera were clustered in a highly supported monophyletic group. Conclusions: These results indicate that lethal Amanita species have the genetic capacity to produce numerous cyclopeptides, most of which are unknown, while lethal Galerina and Lepiota species seem to only have the genetic capacity to produce α-amanitin. Additionally, the POPB phylogeny of Amanita , Galerina and Lepiota conflicts with the taxonomic status of the three genera, suggesting that underlying horizontal gene transfer has occurred among these three genera.


2016 ◽  
Author(s):  
Prabhakar Ghorpade ◽  
Avinash Pange ◽  
Bhaskar Sharma

Methionyl tRNA synthetase is single copy informational gene in Salmonella typhimurium. Informational genes are more conserved than operational genes. In this study we had analyzed HGT events within MetG sequences of different bacterial genera. A species tree based on 16srRNA sequences of the same genus was drawn evaluated against the generally accepted species tree of the bacteria. MetG phylogenetic tree was evaluated against the 16srRNAS tree and HGT event identified. Similarly phyla trees were made and HGT event identified. 24 HGT events were identified between genus and 11 within phyla. MetG is a considered as conserved gene finding so many HGT event in this gene indicate that horizontal gene transfer is very common in this gene. Manual tree making for phyla could help to understand phylogenetic relationships between very large trees.


Author(s):  
Matthew A Spence ◽  
Matthew D Mortimer ◽  
Ashley M Buckle ◽  
Bui Quang Minh ◽  
Colin J Jackson

Abstract Serine protease inhibitors (serpins) are found in all kingdoms of life and play essential roles in multiple physiological processes. Owing to the diversity of the superfamily, phylogenetic analysis is challenging and prokaryotic serpins have been speculated to have been acquired from Metazoa through horizontal gene transfer due to their unexpectedly high homology. Here, we have leveraged a structural alignment of diverse serpins to generate a comprehensive 6,000-sequence phylogeny that encompasses serpins from all kingdoms of life. We show that in addition to a central “hub” of highly conserved serpins, there has been extensive diversification of the superfamily into many novel functional clades. Our analysis indicates that the hub proteins are ancient and are similar because of convergent evolution, rather than the alternative hypothesis of horizontal gene transfer. This work clarifies longstanding questions in the evolution of serpins and provides new directions for research in the field of serpin biology.


2020 ◽  
Author(s):  
Zhengmi He ◽  
Pan Long ◽  
Fang Fang ◽  
Sainan Li ◽  
Ping Zhang ◽  
...  

Abstract Background Amanitin-producing mushrooms, mainly distributed in the genera Amanita , Galerina and Lepiota , possess MSDIN gene family for the biosynthesis of many cyclopeptides catalyzed by prolyl oligopeptidase (POP). Recently, transcriptome sequencing has proven to be a efficient way to mine MSDIN and POP genes in these lethal mushrooms. Until now, only A . palloides and A. bisporigera from North America and A . exitialis from Asia have been studied based on transcriptome analysis. However, MSDIN and POP genes of many amanitin-producing mushrooms in China remain unstudied, and hence the transcriptomes of these speices deserve to be analysed. Results In this study, the MSDIN and POP genes from ten Amanita species, two Galerina species and Lepiota venenata were studied and the phylogenetic relationships of their MSDIN and POP genes were analyzed. Through transcriptome sequencing and PCR cloning, 19 POP genes and 151 MSDIN genes predicted to encode 98 non-duplicated cyclopeptides, including α-amanitin, β-amanitin, phallacidin, phalloidin and 94 unknown peptides, were found in these species. Phylogenetic analysis showed that toxin peptide genes were clustered depending on the chemical substance within genus while depending on the taxonomy between genus and that the POPA genes of Amanita , Galerina and Lepiota were clustered and separated in three different groups, but the POPB genes of the three distinct genera were clustered in a highly monophyletic group. Conclusions These results above indicate that lethal Amanita species have the genetic capacity to produce numerous cyclopeptides, most of which are unknown, while lethal Galerina and Lepiota species seem to only have the genetic capacity to produce α-amanitin. Additionally, the POPB phylogeny of Amanita , Galerina and Lepiota conflicts with the taxonomic status of the three genera, suggesting that horizontal gene transfer might occur among the three genera.


Genetics ◽  
2001 ◽  
Vol 158 (3) ◽  
pp. 949-957 ◽  
Author(s):  
Eitan Rubin ◽  
Gila Lithwick ◽  
Avraham A Levy

Abstract The maize transposon Activator (Ac) was the first mobile DNA element to be discovered. Since then, other elements were found that share similarity to Ac, suggesting that it belongs to a transposon superfamily named hAT after hobo from Drosophila, Ac from maize, and Tam3 from snapdragon. We addressed the structure and evolution of hAT elements by developing new tools for transposon mining and searching the public sequence databases for the hallmarks of hAT elements, namely the transposase and short terminal inverted repeats (TIRs) flanked by 8-bp host duplications. We found 147 hAT-related sequences in plants, animals, and fungi. Six conserved blocks could be identified in the transposase of most hAT elements. A total of 41 hAT sequences were flanked by TIRs and 8-bp host duplications and, out of these, 34 sequences had TIRs similar to the consensus determined in this work, suggesting that they are active or recently active transposons. Phylogenetic analysis and clustering of hAT sequences suggest that the hAT superfamily is very ancient, probably predating the plant-fungi-animal separation, and that, unlike previously proposed, there is no evidence that horizontal gene transfer was involved in the evolution of hAT elements.


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