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Biomolecules Nov 2021Plastids are membrane-bound organelles that bestow phototrophic abilities to eukaryotes [...].
Plastids are membrane-bound organelles that bestow phototrophic abilities to eukaryotes [...].
Topics: Biological Evolution; Dinoflagellida; Phylogeny; Plastids; Symbiosis
PubMed: 34827692
DOI: 10.3390/biom11111694 -
Journal of Phycology Aug 2021The phylogenetic diversity of Ochrophyta, a diverse and ecologically important radiation of algae, is still incompletely understood even at the level of the principal...
The phylogenetic diversity of Ochrophyta, a diverse and ecologically important radiation of algae, is still incompletely understood even at the level of the principal lineages. One taxon that has eluded simple classification is the marine flagellate genus Olisthodiscus. We investigated Olisthodiscus luteus K-0444 and documented its morphological and genetic differences from the NIES-15 strain, which we described as Olisthodiscus tomasii sp. nov. Phylogenetic analyses of combined 18S and 28S rRNA sequences confirmed that Olisthodiscus constitutes a separate, deep, ochrophyte lineage, but its position could not be resolved. To overcome this problem, we sequenced the plastid genome of O. luteus K-0444 and used the new data in multigene phylogenetic analyses, which suggested that Olisthodiscus is a sister lineage of the class Pinguiophyceae within a broader clade additionally including Chrysophyceae, Synchromophyceae, and Eustigmatophyceae. Surprisingly, the Olisthodiscus plastid genome contained three genes, ycf80, cysT, and cysW, inherited from the rhodophyte ancestor of the ochrophyte plastid yet lost from all other ochrophyte groups studied so far. Combined with nuclear genes for CysA and Sbp proteins, Olisthodiscus is the only known ochrophyte possessing a plastidial sulfate transporter SulT. In addition, the finding of a cemA gene in the Olisthodiscus plastid genome and an updated phylogenetic analysis ruled out the previously proposed hypothesis invoking horizontal cemA transfer from a green algal plastid into Synurales. Altogether, Olisthodiscus clearly represents a novel phylogenetically distinct ochrophyte lineage, which we have proposed as a new class, Olisthodiscophyceae.
Topics: Genome, Plastid; Phylogeny; Plants; Plastids; Stramenopiles
PubMed: 33655496
DOI: 10.1111/jpy.13155 -
Methods in Molecular Biology (Clifton,... 2021The plastid genome (plastome ) has proved a valuable source of data for evaluating evolutionary relationships among angiosperms. Through basic and applied approaches,...
The plastid genome (plastome ) has proved a valuable source of data for evaluating evolutionary relationships among angiosperms. Through basic and applied approaches, plastid transformation technology offers the potential to understand and improve plant productivity, providing food, fiber, energy, and medicines to meet the needs of a burgeoning global population. The growing genomic resources available to both phylogenetic and biotechnological investigations is allowing novel insights and expanding the scope of plastome research to encompass new species. In this chapter, we present an overview of some of the seminal and contemporary research that has contributed to our current understanding of plastome evolution and attempt to highlight the relationship between evolutionary mechanisms and the tools of plastid genetic engineering.
Topics: Evolution, Molecular; Genes, Plant; Genetic Engineering; Genetic Variation; Genome, Plastid; Magnoliopsida; Phylogeny; Plastids
PubMed: 34028761
DOI: 10.1007/978-1-0716-1472-3_1 -
Genome Biology and Evolution Jun 2023The chloroplast (plastid) arose via the endosymbiosis of a photosynthetic cyanobacterium by a nonphotosynthetic eukaryotic cell ∼1.5 billion years ago. Although the...
The chloroplast (plastid) arose via the endosymbiosis of a photosynthetic cyanobacterium by a nonphotosynthetic eukaryotic cell ∼1.5 billion years ago. Although the plastid underwent rapid evolution by genome reduction, its rate of molecular evolution is low and its genome organization is highly conserved. Here, we investigate the factors that have constrained the rate of molecular evolution of protein-coding genes in the plastid genome. Through phylogenomic analysis of 773 angiosperm plastid genomes, we show that there is substantial variation in the rate of molecular evolution between genes. We demonstrate that the distance of a plastid gene from the likely origin of replication influences the rate at which it has evolved, consistent with time and distance-dependent nucleotide mutation gradients. In addition, we show that the amino acid composition of a gene product constraints its substitution tolerance, limiting its mutation landscape and its corresponding rate of molecular evolution. Finally, we demonstrate that the mRNA abundance of a gene is a key factor in determining its rate of molecular evolution, suggesting an interaction between transcription and DNA repair in the plastid. Collectively, we show that the location, the composition, and the expression of a plastid gene can account for >50% of the variation in its rate of molecular evolution. Thus, these three factors have exerted a substantial limitation on the capacity for adaptive evolution in plastid-encoded genes and ultimately constrained the evolvability of the chloroplast.
Topics: Magnoliopsida; Chloroplasts; Phylogeny; Evolution, Molecular; Genome; Plastids; Genome, Plastid
PubMed: 37279504
DOI: 10.1093/gbe/evad101 -
International Journal of Molecular... Apr 2021Horizontal gene transfer (HGT)- is defined as the acquisition of genetic material from another organism. However, recent findings indicate a possible role of HGT in the... (Review)
Review
Horizontal gene transfer (HGT)- is defined as the acquisition of genetic material from another organism. However, recent findings indicate a possible role of HGT in the acquisition of traits with adaptive significance, suggesting that HGT is an important driving force in the evolution of eukaryotes as well as prokaryotes. It has been noted that, in eukaryotes, HGT is more prevalent than originally thought. Mitochondria and chloroplasts lost a large number of genes after their respective endosymbiotic events occurred. Even after this major content loss, organelle genomes still continue to lose their own genes. Many of these are subsequently acquired by intracellular gene transfer from the original plastid. The aim of our review was to elucidate the role of chloroplasts in the transfer of genes. This review also explores gene transfer involving mitochondrial and nuclear genomes, though recent studies indicate that chloroplast genomes are far more active in HGT as compared to these other two DNA-containing cellular compartments.
Topics: Cell Nucleus; Chloroplasts; Endophytes; Gene Transfer, Horizontal; Genome; Mitochondria; Plants; Plastids
PubMed: 33923118
DOI: 10.3390/ijms22094484 -
Current Protocols Apr 2021Plastids (chloroplasts) are the defining organelles of plants and eukaryotic algae. In addition to performing photosynthesis, plastids harbor numerous other metabolic...
Plastids (chloroplasts) are the defining organelles of plants and eukaryotic algae. In addition to performing photosynthesis, plastids harbor numerous other metabolic pathways and therefore are often referred to as the biosynthetic center of the plant cell. The chloroplasts of seed plants possess dozens of copies of a circular genome of ∼150 kb that contains a conserved set of 120 to 130 genes. The engineering of this genome by genetic transformation is technically challenging and currently only possible in a small number of species. In this article, we describe the methods involved in generating stable chloroplast-transformed (transplastomic) plants in the model species Arabidopsis (Arabidopsis thaliana). The protocols presented here can be applied to (1) target genes in the Arabidopsis chloroplast genome by reverse genetics and (2) express reporter genes or other foreign genes of interest in plastids of Arabidopsis plants. © 2021 The Authors. Basic Protocol 1: Generation of root-derived microcallus material for biolistic transformation Basic Protocol 2: Chloroplast transformation by biolistic bombardment of root-derived microcalli Basic Protocol 3: Regeneration of transplastomic lines and seed production.
Topics: Arabidopsis; Chloroplasts; Plants, Genetically Modified; Plastids; Transformation, Genetic
PubMed: 33905600
DOI: 10.1002/cpz1.103 -
Protist Dec 2023Cryptophytes are single celled protists found in all aquatic environments. They are composed of a heterotrophic genus, Goniomonas, and a largely autotrophic group...
Cryptophytes are single celled protists found in all aquatic environments. They are composed of a heterotrophic genus, Goniomonas, and a largely autotrophic group comprising many genera. Cryptophytes evolved through secondary endosymbiosis between a host eukaryotic heterotroph and a symbiont red alga. This merger resulted in a four-genome system that includes the nuclear and mitochondrial genomes from the host and a second nuclear genome (nucleomorph) and plastid genome inherited from the symbiont. Here, we make use of different genomes (with potentially distinct evolutionary histories) to perform a phylogenomic study of the early history of cryptophytes. Using ultraconserved elements from the host nuclear genome and symbiont nucleomorph and plastid genomes, we produce a three-genome phylogeny of 91 strains of cryptophytes. Our phylogenetic analyses find that that there are three major cryptophyte clades: Clade 1 comprises Chroomonas and Hemiselmis species, Clade 2, a taxonomically rich clade, comprises at least twelve genera, and Clade 3, comprises the heterotrophic Goniomonas species. Each of these major clades include both freshwater and marine species, but subclades within these clades differ in degrees of niche conservatism. Finally, we discuss priorities for taxonomic revision to Cryptophyceae based on previous studies and in light of these phylogenomic analyses.
Topics: Phylogeny; Cryptophyta; Biological Evolution; Eukaryota; Genome, Mitochondrial; Plastids
PubMed: 37935085
DOI: 10.1016/j.protis.2023.125994 -
International Journal of Molecular... Mar 2021Plant prenyllipids, especially isoprenoid chromanols and quinols, are very efficient low-molecular-weight lipophilic antioxidants, protecting membranes and storage... (Review)
Review
Plant prenyllipids, especially isoprenoid chromanols and quinols, are very efficient low-molecular-weight lipophilic antioxidants, protecting membranes and storage lipids from reactive oxygen species (ROS). ROS are byproducts of aerobic metabolism that can damage cell components, they are also known to play a role in signaling. Plants are particularly prone to oxidative damage because oxygenic photosynthesis results in O formation in their green tissues. In addition, the photosynthetic electron transfer chain is an important source of ROS. Therefore, chloroplasts are the main site of ROS generation in plant cells during the light reactions of photosynthesis, and plastidic antioxidants are crucial to prevent oxidative stress, which occurs when plants are exposed to various types of stress factors, both biotic and abiotic. The increase in antioxidant content during stress acclimation is a common phenomenon. In the present review, we describe the mechanisms of ROS (singlet oxygen, superoxide, hydrogen peroxide and hydroxyl radical) production in chloroplasts in general and during exposure to abiotic stress factors, such as high light, low temperature, drought and salinity. We highlight the dual role of their presence: negative (i.e., lipid peroxidation, pigment and protein oxidation) and positive (i.e., contribution in redox-based physiological processes). Then we provide a summary of current knowledge concerning plastidic prenyllipid antioxidants belonging to isoprenoid chromanols and quinols, as well as their structure, occurrence, biosynthesis and function both in ROS detoxification and signaling.
Topics: Antioxidants; Chloroplasts; Chromans; Plastids; Quinones; Reactive Oxygen Species; Terpenes
PubMed: 33799456
DOI: 10.3390/ijms22062950 -
Current Opinion in Plant Biology Oct 2021Chloroplasts and mitochondria evolved from free-living prokaryotic organisms that entered the eukaryotic cell through endosymbiosis. The gradual conversion from... (Review)
Review
Chloroplasts and mitochondria evolved from free-living prokaryotic organisms that entered the eukaryotic cell through endosymbiosis. The gradual conversion from endosymbiont to organelle during the course of evolution was accompanied by the development of a communication system between the host and the endosymbiont, referred to as retrograde signaling or organelle-to-nucleus signaling. In higher plants, plastid-to-nucleus signaling involves multiple signaling pathways necessary to coordinate plastid function and cellular responses to developmental and environmental stimuli. Phylogenetic reconstructions using sequence information from evolutionarily diverse photosynthetic eukaryotes have begun to provide information about how retrograde signaling pathways were adopted and modified in different lineages over time. A tight communication system was likely a major facilitator of plants conquest of the land because it would have enabled the algal ancestors of land plants to better allocate their cellular resources in response to high light and desiccation, the major stressor for streptophyte algae in a terrestrial habitat. In this review, we aim to give an evolutionary perspective on plastid-to-nucleus signaling.
Topics: Biological Evolution; Eukaryota; Photosynthesis; Phylogeny; Plastids; Symbiosis
PubMed: 34390927
DOI: 10.1016/j.pbi.2021.102093 -
Molecular Phylogenetics and Evolution Aug 2021The establishment of a segregate lepisoroid fern genus Ellipinema was mainly to accommodate the isolated position of Lepisorus jakonensis (Polypodiaceae) recovered in...
The establishment of a segregate lepisoroid fern genus Ellipinema was mainly to accommodate the isolated position of Lepisorus jakonensis (Polypodiaceae) recovered in plastid gene tree. Using newly obtained nuclear data, we recovered that Ellipinema and allied genera, such as Lepidomicrosorium, Lemmaphyllum, Neolepisorus, Paragramma, Tricholepidium and Weatherbya are deeply nested within Lepisorus. The nuclear phylogeny showing incongruent phylogenetic placement in comparison with plastid results perhaps indicated ancient hybridization events. The diagnostic morphology characterizing Ellipinema - elliptic scale-like paraphyses, which is shared by all the taxa of sect. Lepisorus and sect. Hymenophyton - falls within the range of continuous variation in the type species Ellipinema jakonense (=Lepisorus jakonensis). Our study, which integrated molecular and morphological data, demonstrates that the segregation of Ellipinema and ×Ellipisorus (= ×Lepinema Li Bing Zhang & Liang Zhang, nom. illeg.) from Lepisorus should be rejected.
Topics: DNA, Plant; Phylogeny; Plastids; Polypodiaceae
PubMed: 33866009
DOI: 10.1016/j.ympev.2021.107176