scholarly journals The Exploration of Novel Regulatory Relationships Drives Haloarchaeal Operon-Like Structural Dynamics over Short Evolutionary Distances

2020 ◽  
Vol 8 (12) ◽  
pp. 1900
Author(s):  
Phillip Seitzer ◽  
Andrew I. Yao ◽  
Ariana Cisneros ◽  
Marc T. Facciotti

Operons are a dominant feature of bacterial and archaeal genome organization. Numerous investigations have related aspects of operon structure to operon function, making operons exemplars for studies aimed at deciphering Nature’s design principles for genomic organization at a local scale. We consider this understanding to be both fundamentally important and ultimately useful in the de novo design of increasingly complex synthetic circuits. Here we analyze the evolution of the genomic context of operon-like structures in a set of 76 sequenced and annotated species of halophilic archaea. The phylogenetic depth and breadth of this dataset allows insight into changes in operon-like structures over shorter evolutionary time scales than have been studied in previous cross-species analysis of operon evolution. Our analysis, implemented in the updated software package JContextExplorer finds that operon-like context as measured by changes in structure frequently differs from a sequence divergence model of whole-species phylogeny and that changes seem to be dominated by the exploration of novel regulatory relationships.

Genes ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 246
Author(s):  
Xiaomeng Chen ◽  
Rui Li ◽  
Yonglin Wang ◽  
Aining Li

An emerging poplar canker caused by the gram-negative bacterium, Lonsdalea populi, has led to high mortality of hybrid poplars Populus × euramericana in China and Europe. The molecular bases of pathogenicity and bark adaptation of L. populi have become a focus of recent research. This study revealed the whole genome sequence and identified putative virulence factors of L. populi. A high-quality L. populi genome sequence was assembled de novo, with a genome size of 3,859,707 bp, containing approximately 3434 genes and 107 RNAs (75 tRNA, 22 rRNA, and 10 ncRNA). The L. populi genome contained 380 virulence-associated genes, mainly encoding for adhesion, extracellular enzymes, secretory systems, and two-component transduction systems. The genome had 110 carbohydrate-active enzyme (CAZy)-coding genes and putative secreted proteins. The antibiotic-resistance database annotation listed that L. populi was resistant to penicillin, fluoroquinolone, and kasugamycin. Analysis of comparative genomics found that L. populi exhibited the highest homology with the L. britannica genome and L. populi encompassed 1905 specific genes, 1769 dispensable genes, and 1381 conserved genes, suggesting high evolutionary diversity and genomic plasticity. Moreover, the pan genome analysis revealed that the N-5-1 genome is an open genome. These findings provide important resources for understanding the molecular basis of the pathogenicity and biology of L. populi and the poplar-bacterium interaction.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Fengbin Wang ◽  
Ordy Gnewou ◽  
Charles Modlin ◽  
Leticia C. Beltran ◽  
Chunfu Xu ◽  
...  

AbstractThe exquisite structure-function correlations observed in filamentous protein assemblies provide a paradigm for the design of synthetic peptide-based nanomaterials. However, the plasticity of quaternary structure in sequence-space and the lability of helical symmetry present significant challenges to the de novo design and structural analysis of such filaments. Here, we describe a rational approach to design self-assembling peptide nanotubes based on controlling lateral interactions between protofilaments having an unusual cross-α supramolecular architecture. Near-atomic resolution cryo-EM structural analysis of seven designed nanotubes provides insight into the designability of interfaces within these synthetic peptide assemblies and identifies a non-native structural interaction based on a pair of arginine residues. This arginine clasp motif can robustly mediate cohesive interactions between protofilaments within the cross-α nanotubes. The structure of the resultant assemblies can be controlled through the sequence and length of the peptide subunits, which generates synthetic peptide filaments of similar dimensions to flagella and pili.


Plants ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 1261
Author(s):  
Robin Lardon ◽  
Danny Geelen

Plant regeneration is essential for survival upon wounding and is, hence, considered to be a strong natural selective trait. The capacity of plant tissues to regenerate in vitro, however, varies substantially between and within species and depends on the applied incubation conditions. Insight into the genetic factors underlying this variation may help to improve numerous biotechnological applications that exploit in vitro regeneration. Here, we review the state of the art on the molecular framework of de novo shoot organogenesis from root explants in Arabidopsis, which is a complex process controlled by multiple quantitative trait loci of various effect sizes. Two types of factors are distinguished that contribute to natural regenerative variation: master regulators that are conserved in all experimental systems (e.g., WUSCHEL and related homeobox genes) and conditional regulators whose relative role depends on the explant and the incubation settings. We further elaborate on epigenetic variation and protocol variables that likely contribute to differential explant responsivity within species and conclude that in vitro shoot organogenesis occurs at the intersection between (epi) genetics, endogenous hormone levels, and environmental influences.


Author(s):  
Corrinne E Grover ◽  
Daojun Yuan ◽  
Mark A Arick ◽  
Emma R Miller ◽  
Guanjing Hu ◽  
...  

Abstract Cotton is an important textile crop whose gains in production over the last century have been challenged by various diseases. Because many modern cultivars are susceptible to several pests and pathogens, breeding efforts have included attempts to introgress wild, naturally resistant germplasm into elite lines. Gossypium stocksii is a wild cotton species native to Africa, which is part of a clade of vastly understudied species. Most of what is known about this species comes from pest resistance surveys and/or breeding efforts, which suggests that G. stocksii could be a valuable reservoir of natural pest resistance. Here we present a high-quality de novo genome sequence for G. stocksii. We compare the G. stocksii genome with resequencing data from a closely related, understudied species (G. somalense) to generate insight into the relatedness of these cotton species. Finally, we discuss the utility of the G. stocksii genome for understanding pest resistance in cotton, particularly resistance to cotton leaf curl virus.


2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Jinlong Huang ◽  
Yiping Zhao ◽  
Dongyi Bai ◽  
Wunierfu Shiraigol ◽  
Bei Li ◽  
...  

Abstract The donkey, like the horse, is a promising model for exploring karyotypic instability. We report the de novo whole-genome assemblies of the donkey and the Asiatic wild ass. Our results reflect the distinct characteristics of donkeys, including more effective energy metabolism and better immunity than horses. The donkey shows a steady demographic trajectory. We detected abundant satellite sequences in some inactive centromere regions but not in neocentromere regions, while ribosomal RNAs frequently emerged in neocentromere regions but not in the obsolete centromere regions. Expanded miRNA families and five newly discovered miRNA target genes involved in meiosis may be associated with fast karyotype evolution. APC/C, controlling sister chromatid segregation, cytokinesis and the establishment of the G1 cell cycle phase were identified by analysis of miRNA targets and rapidly evolving genes.


2016 ◽  
Vol 4 (2) ◽  
Author(s):  
Anne Fischer ◽  
Ivette Santana-Cruz ◽  
Lillian Wambua ◽  
Cassandra Olds ◽  
Charles Midega ◽  
...  

Phytoplasmas are bacterial plant pathogens with devastating impact on agricultural production worldwide. In eastern Africa, Napier grass stunt disease causes serious economic losses in the smallholder dairy industry. This draft genome sequence of “ Candidatus Phytoplasma oryzae” strain Mbita1 provides insight into its genomic organization and the molecular basis of pathogenicity.


Genetics ◽  
1991 ◽  
Vol 129 (3) ◽  
pp. 707-716 ◽  
Author(s):  
J S Horton ◽  
C A Raper

Abstract A DNA sequence capable of inducing the de novo development of fruiting bodies (mushrooms) when integrated into the genome of unmated, nonfruiting strains of the Basidiomycete Schizophyllum commune has been isolated and partially characterized. This sequence, designated FRT1, overrides the normal requirement of a mating interaction for fruiting in this organism. It has been shown to integrate stably in different chromosome locations and appears to be trans-acting. It also enhances the normal process of fruiting that occurs after mating. Additional DNA sequences with similarity to FRT1 were detected within the genome of the strain of origin by hybridization of labeled FRT1 DNA to blots of digested genomic DNAs. FRT1 and the genomic sequences similar to it were shown to be genetically linked. Southern hybridization experiments suggested sequence divergence at the FRT1 locus between different strains of S. commune. A testable model for how FRT1 may act as a key element in the pathway for the differentiation of fruiting bodies is presented as a working hypothesis for further investigation.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Mochamad Syaifudin ◽  
Michaël Bekaert ◽  
John B. Taggart ◽  
Kerry L. Bartie ◽  
Stefanie Wehner ◽  
...  

Abstract Tilapias (family Cichlidae) are of importance in aquaculture and fisheries. Hybridisation and introgression are common within tilapia genera but are difficult to analyse due to limited numbers of species-specific genetic markers. We tested the potential of double digested restriction-site associated DNA (ddRAD) sequencing for discovering single nucleotide polymorphism (SNP) markers to distinguish between 10 tilapia species. Analysis of ddRAD data revealed 1,371 shared SNPs in the de novo-based analysis and 1,204 SNPs in the reference-based analysis. Phylogenetic trees based on these two analyses were very similar. A total of 57 species-specific SNP markers were found among the samples analysed of the 10 tilapia species. Another set of 62 species-specific SNP markers was identified from a subset of four species which have often been involved in hybridisation in aquaculture: 13 for Oreochromis niloticus, 23 for O. aureus, 12 for O. mossambicus and 14 for O. u. hornorum. A panel of 24 SNPs was selected to distinguish among these four species and validated using 91 individuals. Larger numbers of SNP markers were found that could distinguish between the pairs of species within this subset. This technique offers potential for the investigation of hybridisation and introgression among tilapia species in aquaculture and in wild populations.


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