scholarly journals Comparative development of simple and compound leaves in the genus Cecropia

Botany ◽  
2017 ◽  
Vol 95 (2) ◽  
pp. 185-193 ◽  
Author(s):  
Michael S. Ogden ◽  
Christian R. Lacroix
Keyword(s):  
Shoot Apex ◽  
Leaf Shape ◽  
Leaf Primordium ◽  
Developmental Pathways ◽  
Signalling Pathways ◽  
Evolutionary Divergence ◽  
Molecular Processes ◽  
Closely Related Species ◽  
Nonsignificant Difference ◽  
High Degree

Plants develop leaves that range from simple to compound in shape. The evolutionary divergence of simple and compound leaves has spurred research into identifying the cellular and molecular processes involved in determining leaf shape. The roles of various genes and signalling pathways have been characterized in specifying leaf shape; however, few studies have investigated leaf primordium structure and shoot apex organization throughout the development of both simple and compound leaves. Using Cecropia obtusa Trécul and Cecropia sciadophylla Martius, two putatively closely related species bearing simple palmate and palmately-compound leaves, respectively, we compared the morphogenesis of leaves of both species at the shoot apex. Analysis of shoot apices using scanning electron microscopy yielded a nonsignificant difference in leaf primordium divergence angles and plastochron ratios, suggesting that divergence of the two leaf types occurred independently of primordium organization and growth rate at the shoot apex. Qualitative analysis of primordium initiation and morphogenesis revealed that both species share highly homologous development, as primordium structure and lobe/leaflet initiation sites are complementary in both leaf types. Our observations suggest a high degree of conserved ontogeny in the developmental pathways underlying the morphogenesis of simple palmate and palmately-compound leaves in these two species.

scholarly journals Mangrove tree (Avicennia marina): insight into chloroplast genome evolutionary divergence and its comparison with related species from family Acanthaceae

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sajjad Asaf ◽  
Abdul Latif Khan ◽  
Muhammad Numan ◽  
Ahmed Al-Harrasi
Keyword(s):  
Chloroplast Genome ◽  
Related Species ◽  
Evolutionary Genetics ◽  
Single Copy ◽  
Avicennia Marina ◽  
Pairwise Distance ◽  
Trna Genes ◽  
Evolutionary Divergence ◽  
Mangrove Tree ◽  
High Degree

AbstractAvicennia marina (family Acanthaceae) is a halotolerant woody shrub that grows wildly and cultivated in the coastal regions. Despite its importance, the species suffers from lack of genomic datasets to improve its taxonomy and phylogenetic placement across the related species. Here, we have aimed to sequence the plastid genome of A. marina and its comparison with related species in family Acanthaceae. Detailed next-generation sequencing and analysis showed a complete chloroplast genome of 150,279 bp, comprising 38.6% GC. Genome architecture is quadripartite revealing large single copy (82,522 bp), small single copy (17,523 bp), and pair of inverted repeats (25,117 bp). Furthermore, the genome contains 132 different genes, including 87 protein-coding genes, 8 rRNA, 37 tRNA genes, and 126 simple sequence repeats (122 mononucleotide, 2 dinucleotides, and 2 trinucleotides). Interestingly, about 25 forward, 15 reversed and 14 palindromic repeats were also found in the A. marina. High degree synteny was observed in the pairwise alignment with related genomes. The chloroplast genome comparative assessment showed a high degree of sequence similarity in coding regions and varying divergence in the intergenic spacers among ten Acanthaceae species. The pairwise distance showed that A. marina exhibited the highest divergence (0.084) with Justicia flava and showed lowest divergence with Aphelandra knappiae (0.059). Current genomic datasets are a valuable resource for investigating the population and evolutionary genetics of family Acanthaceae members’ specifically A. marina and related species.

scholarly journals Comparative assessment of genetic diversity in wild and primitive cultivated barley in a center of diversity.

Genetics ◽  
1988 ◽  
Vol 119 (4) ◽  
pp. 981-990
Author(s):  
S Jana ◽  
L N Pietrzak
Keyword(s):  
Genetic Diversity ◽  
Eastern Mediterranean ◽  
Hordeum Spontaneum ◽  
Hordeum Vulgare L ◽  
Closely Related Species ◽  
Mediterranean Countries ◽  
Isozyme Loci ◽  
Cultivated Barley ◽  
Multilocus Associations ◽  
High Degree

Abstract Wild barley (Hordeum spontaneum K.) and indigenous primitive varieties of cultivated barley (Hordeum vulgare L.), collected from 43 locations in four eastern Mediterranean countries, Jordan, Syria, Turkey and Greece, were electrophoretically assayed for genetic diversity at 16 isozyme loci. Contrary to a common impression, cultivated barley populations were found to maintain a level of diversity similar to that in its wild progenitor species. Apportionment of overall diversity in the region showed that in cultivated barley within-populations diversity was of higher magnitude than the between-populations component. Neighboring populations of wild and cultivated barleys showed high degree of genetic identity. Groups of 3 or 4 isozyme loci were analyzed to detect associations among loci. Multilocus associations of varying order were detected for all three groups chosen for the analysis. Some of the association terms differed between the two species in the region. Although there was no clear evidence for decrease in diversity attributable to the domestication of barley in the region, there was an indication of different multilocus organizations in the two closely related species.

scholarly journals Marine Prasinovirus Genomes Show Low Evolutionary Divergence and Acquisition of Protein Metabolism Genes by Horizontal Gene Transfer

2010 ◽  
Vol 84 (24) ◽  
pp. 12555-12563 ◽  
Author(s):  
Hervé Moreau ◽  
Gwenael Piganeau ◽  
Yves Desdevises ◽  
Richard Cooke ◽  
Evelyne Derelle ◽  
...  
Keyword(s):  
Gene Transfer ◽  
Viral Evolution ◽  
Genome Comparison ◽  
Evolutionary Divergence ◽  
Gene Repertoire ◽  
Whole Genomes ◽  
Complete Sequences ◽  
Virus Genomes ◽  
High Degree ◽  
Ostreococcus Lucimarinus

ABSTRACT Although marine picophytoplankton are at the base of the global food chain, accounting for half of the planetary primary production, they are outnumbered 10 to 1 and are largely controlled by hugely diverse populations of viruses. Eukaryotic microalgae form a ubiquitous and particularly dynamic fraction of such plankton, with environmental clone libraries from coastal regions sometimes being dominated by one or more of the three genera Bathycoccus, Micromonas, and Ostreococcus (class Prasinophyceae). The complete sequences of two double-stranded (dsDNA) Bathycoccus, one dsDNA Micromonas, and one new dsDNA Ostreococcus virus genomes are described. Genome comparison of these giant viruses revealed a high degree of conservation, both for orthologous genes and for synteny, except for one 36-kb inversion in the Ostreococcus lucimarinus virus and two very large predicted proteins in Bathycoccus prasinos viruses. These viruses encode a gene repertoire of certain amino acid biosynthesis pathways never previously observed in viruses that are likely to have been acquired from lateral gene transfer from their host or from bacteria. Pairwise comparisons of whole genomes using all coding sequences with homologous counterparts, either between viruses or between their corresponding hosts, revealed that the evolutionary divergences between viruses are lower than those between their hosts, suggesting either multiple recent host transfers or lower viral evolution rates.

Evolutionary conservatism will limit responses to climate change in the tropics

2021 ◽  
Vol 17 (10) ◽  
Author(s):  
Ethan B. Linck ◽  
Benjamin G. Freeman ◽  
C. Daniel Cadena ◽  
Cameron K. Ghalambor
Keyword(s):  
Thermal Tolerance ◽  
Species Turnover ◽  
Tropical Species ◽  
Evolutionary Divergence ◽  
Closely Related Species ◽  
Tropical Mountains ◽  
Low Latitudes ◽  
Parapatric Speciation ◽  
The Tropics

Rapid species turnover in tropical mountains has fascinated biologists for centuries. A popular explanation for this heightened beta diversity is that climatic stability at low latitudes promotes the evolution of narrow thermal tolerance ranges, leading to local adaptation, evolutionary divergence and parapatric speciation along elevational gradients. However, an emerging consensus from research spanning phylogenetics, biogeography and behavioural ecology is that this process rarely, if ever, occurs. Instead, closely related species typically occupy a similar elevational niche, while species with divergent elevational niches tend to be more distantly related. These results suggest populations have responded to past environmental change not by adapting and diverging in place, but instead by shifting their distributions to tightly track climate over time. We argue that tropical species are likely to respond similarly to ongoing and future climate warming, an inference supported by evidence from recent range shifts. In the absence of widespread in situ adaptation to new climate regimes by tropical taxa, conservation planning should prioritize protecting large swaths of habitat to facilitate movement.

Intracellular signalling

2020 ◽  
pp. 256-265
Author(s):  
R. Andres Floto
Keyword(s):  
Signal Transduction ◽  
Plasma Membrane ◽  
Cell Surface ◽  
Intracellular Signalling ◽  
Signalling Pathways ◽  
Molecular Processes ◽  
Surface Receptors ◽  
Intracellular Signalling Pathways ◽  
Transmission Of Information ◽  
Effective Transmission

This chapter outlines the general principles of intracellular signalling. Focusing on cell surface receptors, the requirements for effective transmission of information across the plasma membrane are outlined. The principal mechanisms utilized in mammalian signal transduction are described. For each, the pathological consequences of aberrant signalling and means by which pathways can be pharmacologically targeted are described in molecular terms. Intracellular signalling pathways permit the transmission and integration of information within cells. Mammalian receptor signalling relies on only a small number of distinct molecular processes which interact to determine cellular responses. Rapid advances in our knowledge of the mechanisms of intracellular signalling has greatly increased understanding of how cells function physiologically, how they malfunction pathologically, and how their behaviour might be manipulated therapeutically.

The Acceleration of Primordium Initiation as a Component of Floral Evocation in Lolium temulentum L

1996 ◽  
Vol 23 (5) ◽  
pp. 569 ◽  
Author(s):  
LT Evans ◽  
C Blundell
Keyword(s):  
Shoot Apex ◽  
Floral Development ◽  
Growth Retardant ◽  
Leaf Primordium ◽  
Essential Component ◽  
Lolium Temulentum ◽  
Long Day ◽  
External Sign ◽  
Floral Evocation

An acceleration of leaf primordium initiation by the shoot apex frequently follows floral evocation, but after varying intervals. The purpose of the experiments reported here was to define more closely the relation between this reduction of the plastochron and floral evocation, using the long day (LD) plant Lolium temulentum grown under closely controlled conditions.The acceleration begins at floral evocation, on the day after the first LD exposure, and increases after exposure to additional LDs. However, plants too young to be florally evoked by one LD nevertheless manifested an acceleration of primordium initiation, so the acceleration alone is not sufficient for evocation. Single applications of highly florigenic gibberellins (GAs), such as GA5, also accelerate the initiation of primordia and floral development, more so than does the weakly florigenic GA1. By contrast, single applications of the growth retardant Trinexapac-ethyl (CGA 163'935) to plants given one LD largely prevented the acceleration of primordium initiation but without inhibiting floral development. Thus, although the acceleration of primordium initiation by LD or by GA application is the first external sign of floral evocation in L. temulentum, it is neither a sufficient nor an essential component of it.

scholarly journals The Mechanisms of Mating in Pathogenic Fungi—A Plastic Trait

Genes ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 831
Author(s):  
Jane Usher
Keyword(s):  
Fungal Pathogens ◽  
Crop Yields ◽  
Fungal Infections ◽  
Pathogenic Fungi ◽  
Yeast Saccharomyces Cerevisiae ◽  
Closely Related Species ◽  
Sexual And Asexual Reproduction ◽  
Target Dna ◽  
High Degree ◽  
The Impact

The impact of fungi on human and plant health is an ever-increasing issue. Recent studies have estimated that human fungal infections result in an excess of one million deaths per year and plant fungal infections resulting in the loss of crop yields worth approximately 200 million per annum. Sexual reproduction in these economically important fungi has evolved in response to the environmental stresses encountered by the pathogens as a method to target DNA damage. Meiosis is integral to this process, through increasing diversity through recombination. Mating and meiosis have been extensively studied in the model yeast Saccharomyces cerevisiae, highlighting that these mechanisms have diverged even between apparently closely related species. To further examine this, this review will inspect these mechanisms in emerging important fungal pathogens, such as Candida, Aspergillus, and Cryptococcus. It shows that both sexual and asexual reproduction in these fungi demonstrate a high degree of plasticity.

scholarly journals Pipeline for the Rapid Development of Cytogenetic Markers Using Genomic Data of Related Species

Genes ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 113 ◽  
Author(s):  
Pavel Kroupin ◽  
Victoria Kuznetsova ◽  
Dmitry Romanov ◽  
Alina Kocheshkova ◽  
Gennady Karlov ◽  
...  
Keyword(s):  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Genome Sequence ◽  
Related Species ◽  
Evolutionary Divergence ◽  
Whole Genome ◽  
Target Genome ◽  
Target Species ◽  
Closely Related Species ◽  
Chromosome Markers

Repetitive DNA including tandem repeats (TRs) is a significant part of most eukaryotic genomes. TRs include rapidly evolving satellite DNA (satDNA) that can be shared by closely related species, their abundance may be associated with evolutionary divergence, and they have been widely used for chromosome karyotyping using fluorescence in situ hybridization (FISH). The recent progress in the development of whole-genome sequencing and bioinformatics tools enables rapid and cost-effective searches for TRs including satDNA that can be converted into molecular cytogenetic markers. In the case of closely related taxa, the genome sequence of one species (donor) can be used as a base for the development of chromosome markers for related species or genomes (target). Here, we present a pipeline for rapid and high-throughput screening for new satDNA TRs in whole-genome sequencing of the donor genome and the development of chromosome markers based on them that can be applied in the target genome. One of the main peculiarities of the developed pipeline is that preliminary estimation of TR abundance using qPCR and ranking found TRs according to their copy number in the target genome; it facilitates the selection of the most prospective (most abundant) TRs that can be converted into cytogenetic markers. Another feature of our pipeline is the probe preparation for FISH using PCR with primers designed on the aligned TR unit sequences and the genomic DNA of a target species as a template that enables amplification of a whole pool of monomers inherent in the chromosomes of the target species. We demonstrate the efficiency of the developed pipeline by the example of FISH probes developed for A, B, and R subgenome chromosomes of hexaploid triticale (BBAARR) based on a bioinformatics analysis of the D genome of Aegilops tauschii (DD) whole-genome sequence. Our pipeline can be used to develop chromosome markers in closely related species for comparative cytogenetics in evolutionary and breeding studies.

Protamine-like proteins: evidence for a novel chromatin structure

2002 ◽  
Vol 80 (3) ◽  
pp. 353-361 ◽  
Author(s):  
John D Lewis ◽  
Juan Ausió
Keyword(s):  
Protein Expression ◽  
Chromatin Structure ◽  
Related Species ◽  
Marine Invertebrates ◽  
Protein Sequences ◽  
Careful Examination ◽  
Closely Related Species ◽  
Post Translational Modifications ◽  
High Degree ◽  
Degree Of Heterogeneity

Protamine-like (PL) proteins are DNA-condensing proteins that replace somatic-type histones during spermatogenesis. Their composition suggests a function intermediate to that of histones and protamines. Although these proteins have been well characterized at the chemical level in a large number of species, particularly in marine invertebrates, little is known about the specific structures arising from their interaction with DNA. Speculation concerning chromatin structure is complicated by the high degree of heterogeneity in both the number and size of these proteins, which can vary considerably even between closely related species. After careful examination and comparison of the protein sequences available to date for the PL proteins, we propose a model for a novel chromatin structure in the sperm of these organisms that is mediated by somatic-type histones, which are frequently found associated with these proteins. This structure supports the concept that the PL proteins may represent various evolutionary steps between a sperm-specific histone H1 precursor and true protamines. Potential post-translational modifications and the control of PL protein expression and deposition are also discussed.Key words: protamine-like proteins, histones, chromatin structure, sperm, evolution.

scholarly journals O-glycosylation of SPL transcription factors regulates plant developmental transitions downstream of miR156

2019 ◽  
Author(s):  
Krishna Vasant Mutanwad ◽  
Nicole Neumayer ◽  
Claudia Freitag ◽  
Isabella Zangl ◽  
Doris Lucyshyn
Keyword(s):  
Transcription Factors ◽  
Leaf Growth ◽  
Leaf Shape ◽  
Fine Tuning ◽  
Post Translational Modifications ◽  
Developmental Transitions ◽  
Environmental Signals ◽  
Regulatory Pathways ◽  
Trichome Formation ◽  
High Degree

SUMMARYThe timing of plant developmental transitions is decisive for reproductive success and thus tightly regulated by a number of pathways with a high degree of crosstalk between them. Such complex regulatory pathways often involve post-translational modifications (PTMs), integrating internal and environmental signals. O-glycosylation, the attachment of a single monosaccharide to serine or threonine of nuclear and cytosolic proteins, is one of these PTMs, affecting a number of very diverse proteins. Here we show that mutants in the O-fucosyltransferase SPINDLY (SPY) show accelerated developmental transitions. In plants, the transition from juvenile to adult and later to reproductive phase is controlled by an endogenous pathway regulated by miR156, targeting the SQUAMOSA PROMOTER BINDING PROTEIN (SBP/SPL) family of transcription factors. SPLs regulate a number of developmental processes, such as trichome formation, leaf shape, leaf growth rate and floral transition. We present genetic analysis showing that O-glycosylation regulates transitions independently of miR156 levels, but depending on functional SPLs. Moreover, SPLs interact directly with SPY and are O-glycosylated. Our results suggest a model where O-glycosylation is involved at several steps in the regulation of developmental transitions, and plays an important role in fine-tuning different regulatory pathways.

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