scholarly journals Starvation-induced cell fusion and heterokaryosis frequently escape imperfect allorecognition systems in an asexual fungal pathogen

BMC Biology ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Vasileios Vangalis ◽  
Ilya Likhotkin ◽  
Michael Knop ◽  
Milton A. Typas ◽  
Ioannis A. Papaioannou
Keyword(s):  
Cell Fate ◽  
Cell Fusion ◽  
Evolutionary Dynamics ◽  
Genetic Recombination ◽  
Genetic Material ◽  
Protective Function ◽  
Parasexual Cycle ◽  
Somatic Incompatibility ◽  
Self Recognition ◽  
Different Strains

Abstract Background Asexual fungi include important pathogens of plants and other organisms, and their effective management requires understanding of their evolutionary dynamics. Genetic recombination is critical for adaptability and could be achieved via heterokaryosis — the co-existence of genetically different nuclei in a cell resulting from fusion of non-self spores or hyphae — and the parasexual cycle in the absence of sexual reproduction. Fusion between different strains and establishment of viable heterokaryons are believed to be rare due to non-self recognition systems. Here, we investigate the extent and mechanisms of cell fusion and heterokaryosis in the important asexual plant pathogen Verticillium dahliae. Results We used live-cell imaging and genetic complementation assays of tagged V. dahliae strains to analyze the extent of non-self vegetative fusion, heterokaryotic cell fate, and nuclear behavior. An efficient CRISPR/Cas9-mediated system was developed to investigate the involvement of autophagy in heterokaryosis. Under starvation, non-self fusion of germinating spores occurs frequently regardless of the previously assessed vegetative compatibility of the partners. Supposedly “incompatible” fusions often establish viable heterokaryotic cells and mosaic mycelia, where nuclei can engage in fusion or transfer of genetic material. The molecular machinery of autophagy has a protective function against the destruction of “incompatible” heterokaryons. Conclusions We demonstrate an imperfect function of somatic incompatibility systems in V. dahliae. These systems frequently tolerate the establishment of heterokaryons and potentially the initiation of the parasexual cycle even between strains that were previously regarded as “incompatible.”

scholarly journals Metabolic Control of m6A RNA Modification

Metabolites ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 80
Author(s):  
Joohwan Kim ◽  
Gina Lee
Keyword(s):  
Cell Fate ◽  
Metabolic Pathways ◽  
Epigenetic Modification ◽  
Genetic Material ◽  
Rna Modification ◽  
Cell Fate Decisions ◽  
Disease States ◽  
Evolutionarily Conserved ◽  
Regulate Cell Growth ◽  
Epigenetic Processes

Nutrients and metabolic pathways regulate cell growth and cell fate decisions via epigenetic modification of DNA and histones. Another key genetic material, RNA, also contains diverse chemical modifications. Among these, N6-methyladenosine (m6A) is the most prevalent and evolutionarily conserved RNA modification. It functions in various aspects of developmental and disease states, by controlling RNA metabolism, such as stability and translation. Similar to other epigenetic processes, m6A modification is regulated by specific enzymes, including writers (methyltransferases), erasers (demethylases), and readers (m6A-binding proteins). As this is a reversible enzymatic process, metabolites can directly influence the flux of this reaction by serving as substrates and/or allosteric regulators. In this review, we will discuss recent understanding of the regulation of m6A RNA modification by metabolites, nutrients, and cellular metabolic pathways.

scholarly journals Dark Earths and manioc cultivation in Central Amazonia: a window on pre-Columbian agricultural systems?

2008 ◽  
Vol 3 (2) ◽  
pp. 175-194 ◽  
Author(s):  
James A. Fraser ◽  
Charles Roland Clement
Keyword(s):  
Evolutionary Dynamics ◽  
Genetic Material ◽  
Agricultural Practices ◽  
Population Pressure ◽  
Soil Types ◽  
Terra Preta ◽  
Anthropological Study ◽  
Central Amazonia ◽  
Madeira River ◽  
New Research

Many commentators highlight the fertility of Anthropogenic Dark Earths (ADE), emphasizing their potential for sustainable agriculture. Some scholars believe that terra mulata (the less fertile, more extensive form of ADE) was created by means of agricultural practices used by large settled populations of pre-Columbian farmers. But what was it that these Amerindian farmers were growing? Until recently, scholarly consensus held that manioc does not perform well on ADE. New research on the middle Madeira River is showing, however, that this consensus was premature. In this region, the most common crop in ADE fields is bitter manioc. Farmers there have various landraces of manioc that they believe yield particularly well on ADE, and logically plant more of these varieties on ADE. Aspects of the behaviour and perception of manioc cultivation among 52 farmers at the community of Barro Alto were measured quantitatively on four terra firme soil types (Terra Preta, Terra Mulata, Oxisols and Ultisols). These farmers plant different configurations of landraces in different soils, according to their perception of the suitability of particular landraces and their characteristics to certain soil types and successional processes. This, in turn, shapes selective pressures on these varieties, as new genetic material incorporated from volunteer seedlings is more likely to contain traits present in the most prevalent landrace(s) in each soil type. Owing to localized population pressure at Barro Alto, manioc is under more intensive cultivation systems, with shorter cropping periods (5-10 months) and shorter fallow periods (1-2 years). The outcome of these processes is different co-evolutionary dynamics on ADE as opposed to non-anthropogenic soils. Further anthropological study of manioc swiddening in one of the richest agricultural environments in Amazonia can fill a gap in the literature, thus opening an additional window on the pre-Columbian period.

scholarly journals Genetic Analysis of Powassan virus Genotypes Circulating in North America [University of Findlay]

2019 ◽  
Author(s):  
Kristen Huseman ◽  
Abby L Levitt
Keyword(s):  
North America ◽  
Host Species ◽  
Evolutionary Dynamics ◽  
Genetic Recombination ◽  
Ixodes Scapularis ◽  
Geographic Location ◽  
Recombination Analysis ◽  
Phenotypic Characters ◽  
Geographical Regions ◽  
Powassan Virus

Powassan virus (POWV), a tick-borne flavivirus, is the only member of the tick-borne encephalitis serogroup found in North America. Two distinct lineages, prototype lineage (POWV, lineage I) and deer tick virus (DVT, lineage II) are maintained in enzootic transmission cycles by different tick species based on different geographical regions. In North America, Ixodes scapularis acts as the primary vector throughout the Northeast, and Ixodes cookei throughout the Midwest and much of Canada. Importantly, the incidence of human disease due to POWV has increased by 671% over the last 18 years; with DVT perhapes being the most worrisome genotype due to the wide spread range and prevalence of the vector species. The aim of this study is to assess the evolutionary dynamics of the POWV/DTV complex using the most current full-genome, envelope, and 3’UTR sequences available. Bayesian phylogenetic inferences support the two distinct, monophyletic lineages corresponding to POWV and DTV. Additional analysis were performed in order to quantify the degree to which viral phenotypic characters (such as geographic location, and host species utilization) are correlated with shared ancestry within the two different genotypes. The results of this phylogeny-trait correlation analysis suggest significant clustering of viral sequence by sample location. Such in situ evolution is compatible with the relatively limited distances traveled by most ticks and their prefered host species. Lastly, genetic recombination analysis shows no evidence of between genotype recombination, however further analysis needs to be conducted using within genotype recombination analysis as recombination events may be restricted to only closely genetically related viruses.

scholarly journals Deciphering the Impact of a Bacterial Infection on Meiotic Recombination in Arabidopsis with Fluorescence Tagged Lines

Genes ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 832
Author(s):  
Ariane Gratias ◽  
Valérie Geffroy
Keyword(s):  
Pseudomonas Syringae ◽  
Meiotic Recombination ◽  
Recombination Rate ◽  
Evolutionary Dynamics ◽  
Genetic Recombination ◽  
Dna Recombination ◽  
Resistance Mechanism ◽  
Sequence Exchange ◽  
Significant Difference ◽  
The Impact

Plants are under strong evolutionary pressure to maintain surveillance against pathogens. One major disease resistance mechanism is based on NB-LRR (NLR) proteins that specifically recognize pathogen effectors. The cluster organization of the NLR gene family could favor sequence exchange between NLR genes via recombination, favoring their evolutionary dynamics. Increasing data, based on progeny analysis, suggest the existence of a link between the perception of biotic stress and the production of genetic diversity in the offspring. This could be driven by an increased rate of meiotic recombination in infected plants, but this has never been strictly demonstrated. In order to test if pathogen infection can increase DNA recombination in pollen meiotic cells, we infected Arabidopsis Fluorescent Tagged Lines (FTL) with the virulent bacteria Pseudomonas syringae. We measured the meiotic recombination rate in two regions of chromosome 5, containing or not an NLR gene cluster. In all tested intervals, no significant difference in genetic recombination frequency between infected and control plants was observed. Although it has been reported that pathogen exposure can sometimes increase the frequency of recombinant progeny in plants, our findings suggest that meiotic recombination rate in Arabidopsis may be resilient to at least some pathogen attack. Alternative mechanisms are discussed.

scholarly journals Fungal clones win the battle, but recombination wins the war

IMA Fungus ◽  
2019 ◽  
Vol 10 (1) ◽  
Author(s):  
André Drenth ◽  
Alistair R. McTaggart ◽  
Brenda D. Wingfield
Keyword(s):  
Sexual Reproduction ◽  
Fungal Pathogen ◽  
Genetic Recombination ◽  
Genetic Material ◽  
Clonal Reproduction ◽  
Changing Environment ◽  
Space And Time ◽  
Pathogen Populations

Abstract Clonal reproduction is common in fungi and fungal-like organisms during epidemics and invasion events. The success of clonal fungi shaped systems for their classification and some pathogens are tacitly treated as asexual. We argue that genetic recombination driven by sexual reproduction must be a starting hypothesis when dealing with fungi for two reasons: (1) Clones eventually crash because they lack adaptability; and (2) fungi find a way to exchange genetic material through recombination, whether sexual, parasexual, or hybridisation. Successful clones may prevail over space and time, but they are the product of recombination and the next successful clone will inevitably appear. Fungal pathogen populations are dynamic rather than static, and they need genetic recombination to adapt to a changing environment.

High levels of genetic diversity inNosema ceranaewithinApis melliferacolonies

Parasitology ◽  
2013 ◽  
Vol 141 (4) ◽  
pp. 475-481 ◽  
Author(s):  
TAMARA GÓMEZ-MORACHO ◽  
XULIO MASIDE ◽  
RAQUEL MARTÍN-HERNÁNDEZ ◽  
MARIANO HIGES ◽  
CAROLINA BARTOLOMÉ
Keyword(s):  
Genetic Recombination ◽  
Population Expansion ◽  
Single Copy ◽  
Recent Population Expansion ◽  
Colony Losses ◽  
Bee Colony ◽  
Host Parasite Interactions ◽  
Recent Origin ◽  
Different Strains ◽  
Host Parasite

SUMMARYNosema ceranaeis a widespread honeybee parasite, considered to be one of the pathogens involved in the colony losses phenomenon. To date, little is known about its intraspecific genetic variability. The few studies onN. ceranaevariation have focused on the subunits of ribosomal DNA, which are not ideal for this purpose and have limited resolution. Here we characterized three single copy loci (Actin, Hsp70andRPB1) in threeN. ceranaeisolates from Hungary and Hawaii. Our results provide evidence of unexpectedly high levels of intraspecific polymorphism, the coexistence of a wide variety of haplotypes within each bee colony, and the occurrence of genetic recombination inRPB1. Most haplotypes are not shared across isolates and derive from a few frequent haplotypes by a reduced number of singletons (mutations that appear usually just once in the sample), which suggest that they have a fairly recent origin. Overall, our data indicate that this pathogen has experienced a recent population expansion. The presence of multiple haplotypes within individual isolates could be explained by the existence of different strains ofN. ceranaeinfecting honeybee colonies in the field which complicates, and must not be overlooked, further analysis of host–parasite interactions.

scholarly journals Recombinant hepatitis C virus in experimentally infected chimpanzees

2007 ◽  
Vol 88 (1) ◽  
pp. 143-147 ◽  
Author(s):  
Fengxiang Gao ◽  
Omana V. Nainan ◽  
Yuri Khudyakov ◽  
Jinfeng Li ◽  
Ying Hong ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Sequence Analysis ◽  
Factor Viii ◽  
Genetic Recombination ◽  
Nucleotide Sequences ◽  
Recombinant Hepatitis ◽  
Rt Pcr ◽  
Crossover Region ◽  
Different Strains

Genetic recombination between different strains of Hepatitis C virus (HCV) was investigated in three chimpanzees inoculated experimentally with factor VIII concentrate containing HCV subgenotypes 1a, 1b, 2b and 3a. A 750 bp long fragment from the HCV envelope region was amplified by RT-PCR and quasispecies were isolated by plasmid cloning. Nucleotide sequences derived from isolated quasispecies were screened for the presence of inter-subgenotypic recombination by using sequence analysis. Recombination between HCV subgenotype 1a and 1b was found in two animals; each recombinant variant differed by location of predicted crossover region or order of subgenotype 1a and 1b sequences.

Genetical society mendel lecture - Sex factors and viruses

1966 ◽  
Vol 164 (995) ◽  
pp. 230-245 ◽  
Keyword(s):  
Genetic Recombination ◽  
Genetic Material ◽  
Turn Of The Century ◽  
Bacterial Chromosome ◽  
Genetic Determinants ◽  
Physico Chemical ◽  
Biological Discovery ◽  
Tools And Techniques ◽  
Micro Organisms ◽  
First Time

At this Symposium we are remembering and honouring the great and revolutionary discoveries of Gregor Mendel, presented to the world 100 years ago this year, which for the first time expressed the basic phenomena of heredity in a concise, analytical and, above all, numerical form and thus laid the foundation of the science of genetics. However, as the title of this symposium implies, we are not met here merely in adulation of Mendel’s genius but rather to review and discuss the fruits which have now matured on the tree which he planted. I think some of these fruits would seem very strange and incomprehensible to Mendel, for over the last two decades we have witnessed another revolution in genetics as dramatic and as pregnant with new potentialities as that of 100 years ago. The basic ingredients of this revolution were, first, the disclosure of systems of genetic recombination in micro-organisms, and especially in bacteria and their viruses, which enormously increased the resolution of genetic analysis; and, secondly, the elucidation by Watson & Crick, in 1953, of the physico-chemical structure of the genetic material, deoxyribonucleic acid—undoubtedly the most important and provocative biological discovery since Mendel. As a result we are now recapitulating the cytogenetical studies and correlations which marked the turn of the century, but this time the precision and refinement of our tools and techniques have increased more than 1000-fold so that we are looking at genetic behaviour and interaction at the level of molecular structure. In this lecture I would like to discuss what, from the Mendelian viewpoint, must be one of the most bizarre forms of sexual heredity, namely, the process of conjugation and genetic recombination in the bacterium Escherichia coli . My reasons for choosing this rather esoteric topic, apart from personal interest, are three. First, the whole mechanism of sexuality in this organism is mediated and controlled by a new kind of genetic element called the sex factor which, like some temperate bacteriophages, is able to exist in alternative states in the cell, either free in the cytoplasm or as an integral part of the bacterial chromosome, and which can properly be construed as a virus with a novel mode of infectivity, as I hope to show. Secondly, a number of essentially similar elements have recently been discovered in bacteria, masquerading under such different disguises as the genetic determinants of antibiotic substances called colicins or as carriers of transmissible drug resistance, so that the sex factor is far from being a unique entity among the bacteria. Thirdly, genetic interactions occur between the sex factor and the bacterial chromosome which confer great flexibility on this system. Some of the situations which are generated by these interactions mimic those found in the cells of higher organisms so that it is possible to construct plausible, though very speculative, models for the evolution of more stable and highly organized genetic systems.

The parasexual cycle in the entomopathogenic fungus Paecilomyces fumoso-roseus (Wize) Brown and Smith

1984 ◽  
Vol 30 (7) ◽  
pp. 922-926 ◽  
Author(s):  
Guy Riba ◽  
Anne M. Ravelojoana
Keyword(s):  
Entomopathogenic Fungus ◽  
Genetic Recombination ◽  
Agar Medium ◽  
Growth Conditions ◽  
Parasexual Cycle ◽  
Auxotrophic Mutants ◽  
Petri Dishes ◽  
Ultraviolet Treatment

Auxotrophic mutants of Paecilomyces fumoso-roseus obtained by ultraviolet treatment were used to demonstrate parasexual recombination. Formation of hybrid diploids was found to be closely related to growth conditions on artificial media and on host insects. One hundred percent of prototrophic hybrids were isolated from mycosed insects, while no more than 1.5% were recovered from the complete agar medium in the Petri dishes. A few haploids (1%) were obtained from hybrid diploids exposed to haploidizing agents. Some of the haploids were segregants which could only have resulted from genetic recombination.

scholarly journals Deep RNA sequencing analysis of syncytialization-related genes during BeWo cell fusion

Reproduction ◽  
2017 ◽  
Vol 153 (1) ◽  
pp. 35-48 ◽  
Author(s):  
Ru Zheng ◽  
Yue Li ◽  
Huiying Sun ◽  
Xiaoyin Lu ◽  
Bao-Fa Sun ◽  
...  
Keyword(s):  
Rna Sequencing ◽  
Cell Fate ◽  
Cell Fusion ◽  
Mapk Pathway ◽  
Differentially Expressed ◽  
Cell Junction ◽  
Bewo Cell ◽  
Sequencing Analysis ◽  
Rna Seq ◽  
Bewo Cells

The syncytiotrophoblast (STB) plays a key role in maintaining the function of the placenta during human pregnancy. However, the molecular network that orchestrates STB development remains elusive. The aim of this study was to obtain broad and deep insight into human STB formation via transcriptomics. We adopted RNA sequencing (RNA-Seq) to investigate genes and isoforms involved in forskolin (FSK)-induced fusion of BeWo cells. BeWo cells were treated with 50 μM FSK or dimethyl sulfoxide (DMSO) as a vehicle control for 24 and 48 h, and the mRNAs at 0, 24 and 48 h were sequenced. We detected 28,633 expressed genes and identified 1902 differentially expressed genes (DEGs) after FSK treatment for 24 and 48 h. Among the 1902 DEGs, 461 were increased and 395 were decreased at 24 h, whereas 879 were upregulated and 763 were downregulated at 48 h. When the 856 DEGs identified at 24 h were traced individually at 48 h, they separated into 6 dynamic patterns via a K-means algorithm, and most were enriched in down–even and up–even patterns. Moreover, the gene ontology (GO) terms syncytium formation, cell junction assembly, cell fate commitment, calcium ion transport, regulation of epithelial cell differentiation and cell morphogenesis involved in differentiation were clustered, and the MAPK pathway was most significantly regulated. Analyses of alternative splicing isoforms detected 123,200 isoforms, of which 1376 were differentially expressed. The present deep analysis of the RNA-Seq data of BeWo cell fusion provides important clues for understanding the mechanisms underlying human STB formation.

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