A presumed genetic system determining the number of spikelets per rachis node in the tribe Triticeae

Abstract We have applied a genetic system for analyzing mutations in Escherichia coli to Deinococcus radiodurans, an extremeophile with an astonishingly high resistance to UV- and ionizing-radiation-induced mutagenesis. Taking advantage of the conservation of the β-subunit of RNA polymerase among most prokaryotes, we derived again in D. radiodurans the rpoB/Rif r system that we developed in E. coli to monitor base substitutions, defining 33 base change substitutions at 22 different base pairs. We sequenced >250 mutations leading to Rif r in D. radiodurans derived spontaneously in wild-type and uvrD (mismatch-repair-deficient) backgrounds and after treatment with N-methyl-N′-nitro-N-nitrosoguanidine (NTG) and 5-azacytidine (5AZ). The specificities of NTG and 5AZ in D. radiodurans are the same as those found for E. coli and other organisms. There are prominent base substitution hotspots in rpoB in both D. radiodurans and E. coli. In several cases these are at different points in each organism, even though the DNA sequences surrounding the hotspots and their corresponding sites are very similar in both D. radiodurans and E. coli. In one case the hotspots occur at the same site in both organisms.

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Cofactors are Remnants of Life’s Origin and Early Evolution

Journal of Molecular Evolution ◽

10.1007/s00239-020-09988-4 ◽

2021 ◽

Vol 89 (3) ◽

pp. 127-133 ◽

Cited By ~ 1

Author(s):

Aaron D. Goldman ◽

Betul Kacar

Keyword(s):

Genetic Information ◽

Evolutionary Biology ◽

Active Sites ◽

Rna World ◽

Genetic System ◽

Early Evolution ◽

Modern Biology ◽

Iron Sulfur Cluster ◽

Adenosyl Methionine ◽

Precursor Rna

AbstractThe RNA World is one of the most widely accepted hypotheses explaining the origin of the genetic system used by all organisms today. It proposes that the tripartite system of DNA, RNA, and proteins was preceded by one consisting solely of RNA, which both stored genetic information and performed the molecular functions encoded by that genetic information. Current research into a potential RNA World revolves around the catalytic properties of RNA-based enzymes, or ribozymes. Well before the discovery of ribozymes, Harold White proposed that evidence for a precursor RNA world could be found within modern proteins in the form of coenzymes, the majority of which contain nucleobases or nucleoside moieties, such as Coenzyme A and S-adenosyl methionine, or are themselves nucleotides, such as ATP and NADH (a dinucleotide). These coenzymes, White suggested, had been the catalytic active sites of ancient ribozymes, which transitioned to their current forms after the surrounding ribozyme scaffolds had been replaced by protein apoenzymes during the evolution of translation. Since its proposal four decades ago, this groundbreaking hypothesis has garnered support from several different research disciplines and motivated similar hypotheses about other classes of cofactors, most notably iron-sulfur cluster cofactors as remnants of the geochemical setting of the origin of life. Evidence from prebiotic geochemistry, ribozyme biochemistry, and evolutionary biology, increasingly supports these hypotheses. Certain coenzymes and cofactors may bridge modern biology with the past and can thus provide insights into the elusive and poorly-recorded period of the origin and early evolution of life.

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High Frequency Recombination During the Sexual Cycle of Dictyostelium discoideum

Genetics ◽

10.1093/genetics/148.4.1829 ◽

1998 ◽

Vol 148 (4) ◽

pp. 1829-1832 ◽

Cited By ~ 1

Author(s):

David Francis

Keyword(s):

Dictyostelium Discoideum ◽

Genetic Map ◽

High Frequency ◽

Cell Biology ◽

Physical Map ◽

Genetic System ◽

Sexual Cycle ◽

Chromosome 2 ◽

New Combinations ◽

Restriction Sites

Abstract Analysis of Dictyostelium development and cell biology has suffered from the lack of an ordinary genetic system whereby genes can be arranged in new combinations. Genetic exchange between two long ignored strains, A2Cycr and WS205 is here reexamined. Alleles which differ in size or restriction sites between these two strains were found for seven genes. Six of these are in two clusters on chromosome 2. Frequencies of recombinant progeny indicate that the genetic map of the two mating strains is colinear with the physical map recently worked out for the standard nonsexual strain, NC4. The rate of recombination is high, about 0.1% per kilobase in three different regions of chromosome 2. This value is comparable to rates found in yeast, and will permit fine dissection of the genome.

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Inferring vascular architecture of the wheat spikelet based on resource allocation in the branched headt (bht-A1) near isogenic lines

Functional Plant Biology ◽

10.1071/fp19041 ◽

2019 ◽

Vol 46 (11) ◽

pp. 1023 ◽

Cited By ~ 1

Author(s):

Gizaw M. Wolde ◽

Thorsten Schnurbusch

Keyword(s):

Dry Matter ◽

Vascular System ◽

Grain Filling ◽

Spikelet Fertility ◽

Dry Matter Accumulation ◽

Near Isogenic Lines ◽

Network Systems ◽

Vascular Architecture ◽

Isogenic Lines ◽

Rachis Node

Substantial genetic and physiological efforts were made to understand the causal factors of floral abortion and grain filling problem in wheat. However, the vascular architecture during wheat spikelet development is surprisingly under-researched. We used the branched headt near-isogenic lines, FL-bht-A1-NILs, to visualise the dynamics of spikelet fertility and dry matter accumulation in spikelets sharing the same rachis node (henceforth Primary Spikelet, PSt, and Secondary Spikelet, SSt). The experiment was conducted after grouping FL-bht-A1-NILs into two groups, where tillers were consistently removed from one group. Our results show differential spikelet fertility and dry matter accumulation between the PSt and SSt, but also showed a concomitant improvement after de-tillering. This suggests a tight regulation of assimilate supply and dry matter accumulation in wheat spikelets. Since PSt and SSt share the same rachis node, the main vascular bundle in the rachis/rachilla is expected to bifurcate to connect each spikelet/floret to the vascular system. We postulate that the vascular structure in the wheat spikelet might even follow Murray’s law, where the wide conduits assigned at the base of the spikelet feed the narrower conduits of the distal florets. We discuss our results based on the two modalities of the vascular network systems in plants.

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Genetic system inPseudomonas alcaligenesNCIB 9867

FEMS Microbiology Letters ◽

10.1111/j.1574-6968.1993.tb05972.x ◽

1993 ◽

Vol 106 (3) ◽

pp. 253-258 ◽

Cited By ~ 2

Author(s):

Chit Laa Poh ◽

Jill M.L. Tham

Keyword(s):

Genetic System

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A dominant lethal genetic system for autocidal control of the Mediterranean fruitfly

Nature Biotechnology ◽

10.1038/nbt1071 ◽

2005 ◽

Vol 23 (4) ◽

pp. 453-456 ◽

Cited By ~ 128

Author(s):

Peng Gong ◽

Matthew J Epton ◽

Guoliang Fu ◽

Sarah Scaife ◽

Alexandra Hiscox ◽

...

Keyword(s):

Genetic System ◽

Dominant Lethal ◽

Autocidal Control ◽

The Mediterranean

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Identification of the ATPase Subunit of the Primary Maltose Transporter in the Hyperthermophilic Anaerobe Thermotoga maritima

Applied and Environmental Microbiology ◽

10.1128/aem.00930-17 ◽

2017 ◽

Vol 83 (18) ◽

Cited By ~ 4

Author(s):

Raghuveer Singh ◽

Derrick White ◽

Paul Blum

Keyword(s):

Thermotoga Maritima ◽

Mutant Cell ◽

Sugar Metabolism ◽

Genetic System ◽

Gene Replacement ◽

Atpase Subunit ◽

Content Type ◽

Fermentative Hydrogen Production ◽

Atpase Subunits ◽

Fermentative Hydrogen

ABSTRACT Thermotoga maritima is a hyperthermophilic anaerobic bacterium that produces molecular hydrogen (H2) by fermentation. It catabolizes a broad range of carbohydrates through the action of diverse ABC transporters. However, in T. maritima and related species, highly similar genes with ambiguous annotation obscure a precise understanding of genome function. In T. maritima, three putative malK genes, all annotated as ATPase subunits, exhibited high identity to each other. To distinguish between these genes, malK disruption mutants were constructed by gene replacement, and the resulting mutant cell lines were characterized. Only a disruption of malK3 produced a defect in maltose catabolism. To verify that the mutant phenotype arose specifically from malK3 inactivation, the malK3 mutation was repaired by recombination, and maltose catabolism was restored. This study demonstrates the importance of a maltose ABC-type transporter and its relationship to sugar metabolism in T. maritima. IMPORTANCE The application and further development of a genetic system was used here to investigate gene paralogs in the hyperthermophile Thermotoga maritima. The occurrence of three ABC transporter ATPase subunits all annotated as malK was evaluated using a combination of genetic and bioinformatic approaches. The results clarify the role of only one malK gene in maltose catabolism in a nonmodel organism noted for fermentative hydrogen production.

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