scholarly journals Genome evolution of the psammophyte Pugionium for desert adaptation and further speciation

2021 ◽  
Vol 118 (42) ◽  
pp. e2025711118
Author(s):  
Quanjun Hu ◽  
Yazhen Ma ◽  
Terezie Mandáková ◽  
Sheng Shi ◽  
Chunlin Chen ◽  
...  
Keyword(s):  
Abiotic Stress ◽  
Stress Responses ◽  
De Novo ◽  
Lignin Biosynthesis ◽  
Gene Families ◽  
Population Genomic ◽  
Interspecific Divergence ◽  
Genomic Analyses ◽  
Environmental Adaptations ◽  
Genome Assemblies

Deserts exert strong selection pressures on plants, but the underlying genomic drivers of ecological adaptation and subsequent speciation remain largely unknown. Here, we generated de novo genome assemblies and conducted population genomic analyses of the psammophytic genus Pugionium (Brassicaceae). Our results indicated that this bispecific genus had undergone an allopolyploid event, and the two parental genomes were derived from two ancestral lineages with different chromosome numbers and structures. The postpolyploid expansion of gene families related to abiotic stress responses and lignin biosynthesis facilitated environmental adaptations of the genus to desert habitats. Population genomic analyses of both species further revealed their recent divergence with continuous gene flow, and the most divergent regions were found to be centered on three highly structurally reshuffled chromosomes. Genes under selection in these regions, which were mainly located in one of the two subgenomes, contributed greatly to the interspecific divergence in microhabitat adaptation.

scholarly journals Structural rearrangements drive extensive genome divergence between symbiotic and free-living Symbiodinium

2019 ◽  
Author(s):  
Raúl A. González-Pech ◽  
Timothy G. Stephens ◽  
Yibi Chen ◽  
Amin R. Mohamed ◽  
Yuanyuan Cheng ◽  
...  
Keyword(s):  
Genome Size ◽  
Molecular Mechanisms ◽  
De Novo ◽  
Sequence Divergence ◽  
Gene Families ◽  
Homologous Gene ◽  
Structural Rearrangements ◽  
Free Living ◽  
Symbiotic Dinoflagellates ◽  
Genome Assemblies

AbstractSymbiodiniaceae are predominantly symbiotic dinoflagellates critical to corals and other reef organisms. Symbiodinium is a basal symbiodiniacean lineage and includes symbiotic and free-living taxa. However, the molecular mechanisms underpinning these distinct lifestyles remain little known. Here, we present high-quality de novo genome assemblies for the symbiotic Symbiodinium tridacnidorum CCMP2592 (genome size 1.3 Gbp) and the free-living Symbiodinium natans CCMP2548 (genome size 0.74 Gbp). These genomes display extensive sequence divergence, sharing only ~1.5% conserved regions (≥90% identity). We predicted 45,474 and 35,270 genes for S. tridacnidorum and S. natans, respectively; of the 58,541 homologous gene families, 28.5% are common to both genomes. We recovered a greater extent of gene duplication and higher abundance of repeats, transposable elements and pseudogenes in the genome of S. tridacnidorum than in that of S. natans. These findings demonstrate that genome structural rearrangements are pertinent to distinct lifestyles in Symbiodinium, and may contribute to the vast genetic diversity within the genus, and more broadly in Symbiodiniaceae. Moreover, the results from our whole-genome comparisons against a free-living outgroup support the notion that the symbiotic lifestyle is a derived trait in, and that the free-living lifestyle is ancestral to, Symbiodinium.

scholarly journals Characterization of Gene Isoforms Related to Cellulose and Lignin Biosynthesis in Kenaf (Hibiscus cannabinus L.) Mutant

Plants ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 631
Author(s):  
Jae Il Lyu ◽  
Rahul Ramekar ◽  
Dong-Gun Kim ◽  
Jung Min Kim ◽  
Min-Kyu Lee ◽  
...  
Keyword(s):  
Single Molecule ◽  
De Novo ◽  
Sequence Similarity ◽  
Molecular Genetic ◽  
Lignin Biosynthesis ◽  
Gene Families ◽  
Hibiscus Cannabinus ◽  
Growth Stages ◽  
Sequencing Platform ◽  
Apical Leaf

Kenaf is a source of fiber and a bioenergy crop that is considered to be a third world crop. Recently, a new kenaf cultivar, "Jangdae," was developed by gamma irradiation. It exhibited distinguishable characteristics such as higher biomass, higher seed yield, and earlier flowering than the wild type. We sequenced and analyzed the transcriptome of apical leaf and stem using Pacific Biosciences single-molecule long-read isoform sequencing platform. De novo assembly yielded 26,822 full-length transcripts with a total length of 59 Mbp. Sequence similarity against protein sequence allowed the functional annotation of 11,370 unigenes. Among them, 10,100 unigenes were assigned gene ontology terms, the majority of which were associated with the metabolic and cellular process. The Kyoto encyclopedia of genes and genomes (KEGG) analysis mapped 8875 of the annotated unigenes to 149 metabolic pathways. We also identified the majority of putative genes involved in cellulose and lignin-biosynthesis. We further evaluated the expression pattern in eight gene families involved in lignin-biosynthesis at different growth stages. In this study, appropriate biotechnological approaches using the information obtained for these putative genes will help to modify the desirable content traits in mutants. The transcriptome data can be used as a reference dataset and provide a resource for molecular genetic studies in kenaf.

scholarly journals Reference Genome for the Highly Transformable Setaria viridis ME034V

2020 ◽  
Vol 10 (10) ◽  
pp. 3467-3478 ◽  
Author(s):  
Peter M. Thielen ◽  
Amanda L. Pendleton ◽  
Robert A. Player ◽  
Kenneth V. Bowden ◽  
Thomas J. Lawton ◽  
...  
Keyword(s):  
De Novo ◽  
Gene Families ◽  
Model Organisms ◽  
Phylogenomic Analysis ◽  
Setaria Viridis ◽  
Sequencing Technology ◽  
Protein Coding ◽  
Genotype Frequencies ◽  
Green Foxtail ◽  
Genome Assemblies

Setaria viridis (green foxtail) is an important model system for improving cereal crops due to its diploid genome, ease of cultivation, and use of C4 photosynthesis. The S. viridis accession ME034V is exceptionally transformable, but the lack of a sequenced genome for this accession has limited its utility. We present a 397 Mb highly contiguous de novo assembly of ME034V using ultra-long nanopore sequencing technology (read N50 = 41kb). We estimate that this genome is largely complete based on our updated k-mer based genome size estimate of 401 Mb for S. viridis. Genome annotation identified 37,908 protein-coding genes and >300k repetitive elements comprising 46% of the genome. We compared the ME034V assembly with two other previously sequenced Setaria genomes as well as to a diversity panel of 235 S. viridis accessions. We found the genome assemblies to be largely syntenic, but numerous unique polymorphic structural variants were discovered. Several ME034V deletions may be associated with recent retrotransposition of copia and gypsy LTR repeat families, as evidenced by their low genotype frequencies in the sampled population. Lastly, we performed a phylogenomic analysis to identify gene families that have expanded in Setaria, including those involved in specialized metabolism and plant defense response. The high continuity of the ME034V genome assembly validates the utility of ultra-long DNA sequencing to improve genetic resources for emerging model organisms. Structural variation present in Setaria illustrates the importance of obtaining the proper genome reference for genetic experiments. Thus, we anticipate that the ME034V genome will be of significant utility for the Setaria research community.

scholarly journals Genome wide survey, evolution and expression analysis of PHD finger genes reveal their diverse roles during the development and abiotic stress responses in Brassica rapa L.

BMC Genomics ◽  
2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Intikhab Alam ◽  
Cui-Cui Liu ◽  
Hong-Liu Ge ◽  
Khadija Batool ◽  
Yan-Qing Yang ◽  
...  
Keyword(s):  
Abiotic Stress ◽  
Plant Growth ◽  
Brassica Rapa ◽  
Expression Analysis ◽  
Stress Responses ◽  
Growth And Development ◽  
Gene Families ◽  
Plant Growth And Development ◽  
Genome Database ◽  
Phd Finger

Abstract Background Plant homeodomain (PHD) finger proteins are widely present in all eukaryotes and play important roles in chromatin remodeling and transcriptional regulation. The PHD finger can specifically bind a number of histone modifications as an “epigenome reader”, and mediate the activation or repression of underlying genes. Many PHD finger genes have been characterized in animals, but only few studies were conducted on plant PHD finger genes to this day. Brassica rapa (AA, 2n = 20) is an economically important vegetal, oilseed and fodder crop, and also a good model crop for functional and evolutionary studies of important gene families among Brassica species due to its close relationship to Arabidopsis thaliana. Results We identified a total of 145 putative PHD finger proteins containing 233 PHD domains from the current version of B. rapa genome database. Gene ontology analysis showed that 67.7% of them were predicted to be located in nucleus, and 91.3% were predicted to be involved in protein binding activity. Phylogenetic, gene structure, and additional domain analyses clustered them into different groups and subgroups, reflecting their diverse functional roles during plant growth and development. Chromosomal location analysis showed that they were unevenly distributed on the 10 B. rapa chromosomes. Expression analysis from RNA-Seq data showed that 55.7% of them were constitutively expressed in all the tested tissues or organs with relatively higher expression levels reflecting their important housekeeping roles in plant growth and development, while several other members were identified as preferentially expressed in specific tissues or organs. Expression analysis of a subset of 18 B. rapa PHD finger genes under drought and salt stresses showed that all these tested members were responsive to the two abiotic stress treatments. Conclusions Our results reveal that the PHD finger genes play diverse roles in plant growth and development, and can serve as a source of candidate genes for genetic engineering and improvement of Brassica crops against abiotic stresses. This study provides valuable information and lays the foundation for further functional determination of PHD finger genes across the Brassica species.

scholarly journals Comparison of 15 dinoflagellate genomes reveals extensive sequence and structural divergence in family Symbiodiniaceae and genus Symbiodinium

BMC Biology ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Raúl A. González-Pech ◽  
Timothy G. Stephens ◽  
Yibi Chen ◽  
Amin R. Mohamed ◽  
Yuanyuan Cheng ◽  
...  
Keyword(s):  
De Novo ◽  
Gene Families ◽  
Specific Gene ◽  
Free Living ◽  
Microbial Eukaryotes ◽  
The Family ◽  
Structural Divergence ◽  
Genome Features ◽  
Genome Divergence ◽  
Genome Assemblies

Abstract Background Dinoflagellates in the family Symbiodiniaceae are important photosynthetic symbionts in cnidarians (such as corals) and other coral reef organisms. Breakdown of the coral-dinoflagellate symbiosis due to environmental stress (i.e. coral bleaching) can lead to coral death and the potential collapse of reef ecosystems. However, evolution of Symbiodiniaceae genomes, and its implications for the coral, is little understood. Genome sequences of Symbiodiniaceae remain scarce due in part to their large genome sizes (1–5 Gbp) and idiosyncratic genome features. Results Here, we present de novo genome assemblies of seven members of the genus Symbiodinium, of which two are free-living, one is an opportunistic symbiont, and the remainder are mutualistic symbionts. Integrating other available data, we compare 15 dinoflagellate genomes revealing high sequence and structural divergence. Divergence among some Symbiodinium isolates is comparable to that among distinct genera of Symbiodiniaceae. We also recovered hundreds of gene families specific to each lineage, many of which encode unknown functions. An in-depth comparison between the genomes of the symbiotic Symbiodinium tridacnidorum (isolated from a coral) and the free-living Symbiodinium natans reveals a greater prevalence of transposable elements, genetic duplication, structural rearrangements, and pseudogenisation in the symbiotic species. Conclusions Our results underscore the potential impact of lifestyle on lineage-specific gene-function innovation, genome divergence, and the diversification of Symbiodinium and Symbiodiniaceae. The divergent features we report, and their putative causes, may also apply to other microbial eukaryotes that have undergone symbiotic phases in their evolutionary history.

scholarly journals Universal nomenclature for oxytocin–vasotocin ligand and receptor families

Nature ◽  
2021 ◽  
Vol 592 (7856) ◽  
pp. 747-755
Author(s):  
Constantina Theofanopoulou ◽  
Gregory Gedman ◽  
James A. Cahill ◽  
Cedric Boeckx ◽  
Erich D. Jarvis
Keyword(s):  
Common Ancestor ◽  
Gene Families ◽  
Evolutionary Relationships ◽  
Segmental Duplications ◽  
Single Receptor ◽  
Genomic Analyses ◽  
Local Duplication ◽  
Specific Receptors ◽  
The Common ◽  
Genome Assemblies

AbstractOxytocin (OXT; hereafter OT) and arginine vasopressin or vasotocin (AVP or VT; hereafter VT) are neurotransmitter ligands that function through specific receptors to control diverse functions1,2. Here we performed genomic analyses on 35 species that span all major vertebrate lineages, including newly generated high-contiguity assemblies from the Vertebrate Genomes Project3,4. Our findings support the claim5 that OT (also known as OXT) and VT (also known as AVP) are adjacent paralogous genes that have resulted from a local duplication, which we infer was through DNA transposable elements near the origin of vertebrates and in which VT retained more of the parental sequence. We identified six major oxytocin–vasotocin receptors among vertebrates. We propose that all six of these receptors arose from a single receptor that was shared with the common ancestor of invertebrates, through a combination of whole-genome and large segmental duplications. We propose a universal nomenclature based on evolutionary relationships for the genes that encode these receptors, in which the genes are given the same orthologous names across vertebrates and paralogous names relative to each other. This nomenclature avoids confusion due to differential naming in the pre-genomic era and incomplete genome assemblies, furthers our understanding of the evolution of these genes, aids in the translation of findings across species and serves as a model for other gene families.

scholarly journals Mutation accumulation in chromosomal inversions maintains wing pattern polymorphism in a butterfly

2019 ◽  
Author(s):  
Paul Jay ◽  
Mathieu Chouteau ◽  
Annabel Whibley ◽  
Héloïse Bastide ◽  
Violaine Llaurens ◽  
...  
Keyword(s):  
Chromosomal Rearrangements ◽  
Mutational Load ◽  
Wing Pattern ◽  
Numerous Species ◽  
Chromosomal Inversions ◽  
Population Genomic ◽  
Genomic Analyses ◽  
Wing Patterns ◽  
Pattern Polymorphism ◽  
Genome Assemblies

While natural selection favours the fittest genotype, polymorphisms are maintained over evolutionary timescales in numerous species. Why these long-lived polymorphisms are often associated with chromosomal rearrangements remains obscure. Combining genome assemblies, population genomic analyses, and fitness assays, we studied the factors maintaining multiple mimetic morphs in the butterfly Heliconius numata. We show that the polymorphism is maintained because three chromosomal inversions controlling wing patterns express a recessive mutational load, which prevents their fixation despite their ecological advantage. Since inversions suppress recombination and hamper genetic purging, their formation fostered the capture and accumulation of deleterious variants. This suggests that many complex polymorphisms, instead of representing adaptations to the existence of alternative ecological optima, could be maintained primarily because chromosomal rearrangements are prone to carrying recessive harmful mutations.

scholarly journals Dynamics of the leaf endoplasmic reticulum modulate β-glucosidase-mediated stress-activated ABA production from its glucosyl ester

2019 ◽  
Vol 71 (6) ◽  
pp. 2058-2071 ◽  
Author(s):  
Yiping Han ◽  
Shunsuke Watanabe ◽  
Hiroshi Shimada ◽  
Atsushi Sakamoto
Keyword(s):  
Endoplasmic Reticulum ◽  
Abiotic Stress ◽  
Stress Responses ◽  
De Novo ◽  
Hydrolytic Activity ◽  
Single Step ◽  
De Novo Biosynthesis ◽  
Glucosyl Ester ◽  
The Relationship ◽  
Hydrolysis Of

Abstract The phytohormone abscisic acid (ABA) is produced via a multistep de novo biosynthesis pathway or via single-step hydrolysis of inactive ABA-glucose ester (ABA-GE). The hydrolysis reaction is catalyzed by β-glucosidase (BG, or BGLU) isoforms localized to various organelles, where they become activated upon stress, but the mechanisms underlying this organelle-specific activation remain unclear. We investigated the relationship between the subcellular distribution and stress-induced activation of BGLU18 (BG1), an endoplasmic reticulum enzyme critical for abiotic stress responses, in Arabidopsis thaliana leaves. High BGLU18 levels were present in leaf petioles, primarily in endoplasmic reticulum bodies. These Brassicaceae-specific endoplasmic reticulum-derived organelles responded dynamically to abiotic stress, particularly drought-induced dehydration, by changing in number and size. Under stress, BGLU18 distribution shifted toward microsomes, which was accompanied by increasing BGLU18-mediated ABA-GE hydrolytic activity and ABA levels in leaf petioles. Under non-stress conditions, impaired endoplasmic reticulum body formation caused a microsomal shift of BGLU18 and increased its enzyme activity; however, ABA levels increased only under stress, probably because ABA-GE is supplied to the endoplasmic reticulum only under these conditions. Loss of BGLU18 delayed dehydration-induced ABA accumulation, suggesting that ABA-GE hydrolysis precedes the biosynthesis. We propose that dynamics of the endoplasmic reticulum modulate ABA homeostasis and abiotic stress responses by activating BGLU18-mediated ABA-GE hydrolysis.

scholarly journals Genome-wide analysis of the lignin toolbox for morus and the roles of lignin related genes in response to zinc stress

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11964
Author(s):  
Nan Chao ◽  
Ting Yu ◽  
Chong Hou ◽  
Li Liu ◽  
Lin Zhang
Keyword(s):  
De Novo ◽  
Expression Profiles ◽  
Lignin Biosynthesis ◽  
Gene Families ◽  
Phenylpropanoid Pathway ◽  
Economic Plant ◽  
Systematic Analysis ◽  
Zinc Stress ◽  
Genome Wide ◽  
Bona Fide

Mulberry (Morus, Moraceae) is an important economic plant with nutritional, medicinal, and ecological values. Lignin in mulberry can affect the quality of forage and the saccharification efficiency of mulberry twigs. The availability of the Morus notabilis genome makes it possible to perform a systematic analysis of the genes encoding the 11 protein families specific to the lignin branch of the phenylpropanoid pathway, providing the core genes for the lignin toolbox in mulberry. We performed genome-wide screening, which was combined with de novo transcriptome data for Morus notabilis and Morus alba variety Fengchi, to identify putative members of the lignin gene families followed by phylogenetic and expression profile analyses. We focused on bona fide clade genes and their response to zinc stress were further distinguished based on expression profiles using RNA-seq and RT-qPCR. We finally identified 31 bona fide genes in Morus notabilis and 25 bona fide genes in Fengchi. The putative function of these bona fide genes was proposed, and a lignin toolbox that comprised 19 genes in mulberry was provided, which will be convenient for researchers to explore and modify the monolignol biosynthesis pathway in mulberry. We also observed changes in the expression of some of these lignin biosynthetic genes in response to stress caused by excess zinc in Fengchi and proposed that the enhanced lignin biosynthesis in lignified organs and inhibition of lignin biosynthesis in leaf is an important response to zinc stress in mulberry.

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