-
Cell Reports Aug 2020Plastid-nucleus genome coordination is crucial for plastid activity, but the mechanisms remain unclear. By treating Arabidopsis plants with the organellar...
Plastid-nucleus genome coordination is crucial for plastid activity, but the mechanisms remain unclear. By treating Arabidopsis plants with the organellar genome-damaging agent ciprofloxacin, we found that plastid genome instability can alter endoreplication and the cell cycle. Similar results are observed in the plastid genome instability mutants of reca1why1why3. Cell division and embryo development are disturbed in the reca1why1why3 mutant. Notably, SMR5 and SMR7 genes, which encode cell-cycle kinase inhibitors, are upregulated in plastid genome instability plants, and the mutation of SMR7 can restore the endoreplication and growth phenotype of reca1why1why3 plants. Furthermore, we establish that the DNA damage response transcription factor SOG1 mediates the alteration of endoreplication and cell cycle triggered by plastid genome instability. Finally, we demonstrate that reactive oxygen species produced in plastids are important for plastid-nucleus genome coordination. Our findings uncover a molecular mechanism for the coordination of plastid and nuclear genomes during plant growth and development.
Topics: Arabidopsis; Arabidopsis Proteins; Cell Cycle; Cell Cycle Proteins; Cell Nucleus; Endoreduplication; Gene Expression Regulation, Plant; Genome, Plant; Genome, Plastid; Genomic Instability; Plant Development; Plastids; Reactive Oxygen Species; Signal Transduction; Transcription Factors
PubMed: 32783941
DOI: 10.1016/j.celrep.2020.108019 -
Progress in Lipid Research Nov 2021Plant carotenoids are essential for photosynthesis and photoprotection and provide colors in the yellow to red range to non-photosynthetic organs such as petals and ripe... (Review)
Review
Plant carotenoids are essential for photosynthesis and photoprotection and provide colors in the yellow to red range to non-photosynthetic organs such as petals and ripe fruits. They are also the precursors of biologically active molecules not only in plants (including hormones and retrograde signals) but also in animals (including retinoids such as vitamin A). A carotenoid-rich diet has been associated with improved health and cognitive capacity in humans, whereas the use of carotenoids as natural pigments is widespread in the agrofood and cosmetic industries. The nutritional and economic relevance of carotenoids has spurred a large number of biotechnological strategies to enrich plant tissues with carotenoids. Most of such approaches to alter carotenoid contents in plants have been focused on manipulating their biosynthesis or degradation, whereas improving carotenoid sink capacity in plant tissues has received much less attention. Our knowledge on the molecular mechanisms influencing carotenoid storage in plants has substantially grown in the last years, opening new opportunities for carotenoid biofortification. Here we will review these advances with a particular focus on those creating extra room for carotenoids in plant cells either by promoting the differentiation of carotenoid-sequestering structures within plastids or by transferring carotenoid production to the cytosol.
Topics: Animals; Biofortification; Carotenoids; Humans; Plant Cells; Plants; Plastids
PubMed: 34530006
DOI: 10.1016/j.plipres.2021.101128 -
Postepy Biochemii Sep 2020Plastoglobules (PGs), as important components of plastids, are involved in many stages of their development: from the chloroplast biogenesis through the... (Review)
Review
Plastoglobules (PGs), as important components of plastids, are involved in many stages of their development: from the chloroplast biogenesis through the chloroplast-chromoplast transformations, and finally in the process of gerontoplast formation. The unique protein and lipid composition of these structures, depending on their location, suggests that PGs are both a reservoir of spare materials and a center for many metabolic reactions. Plastoglobules play an active role in the metabolism of prenylquinones, carotenoids, and jasmonic acid, and are responsible for recycling of the thylakoid disintegration products. Their direct connection with the thylakoids allows for tight relationships between these two structures and redistribution of materials, which contributes to PGs’ role in response to stressful conditions. Moreover, strongly hydrophobic nature of plastoglobules, their specific proteome and a sufficiently simple isolation procedure create extraordinary possibilities of their application in plant biotechnology.
Topics: Chloroplasts; Plant Cells; Plastids; Proteome; Thylakoids
PubMed: 33315313
DOI: 10.18388/pb.2020_347 -
PloS One 2021Several molecular phylogenetic studies of the mistletoe family Loranthaceae have been published such that now the general pattern of relationships among the genera and...
Several molecular phylogenetic studies of the mistletoe family Loranthaceae have been published such that now the general pattern of relationships among the genera and their biogeographic histories are understood. Less is known about species relationships in the larger (> 10 species) genera. This study examines the taxonomically difficult genus Taxillus composed of 35-40 Asian species. The goal was to explore the genetic diversity present in Taxillus plastomes, locate genetically variable hotspots, and test these for their utility as potential DNA barcodes. Using genome skimming, complete plastomes, as well as nuclear and mitochondrial rDNA sequences, were newly generated for eight species. The plastome sequences were used in conjunction with seven publicly available Taxillus sequences and three sequences of Scurrula, a close generic relative. The Taxillus plastomes ranged from 121 to 123 kbp and encoded 90-93 plastid genes. In addition to all of the NADH dehydrogenase complex genes, four ribosomal genes, infA and four intron-containing tRNA genes were lost or pseudogenized in all of the Taxillus and Scurrula plastomes. The topologies of the plastome, mitochondrial rDNA and nuclear rDNA trees were generally congruent, though with discordance at the position of T. chinensis. Several variable regions in the plastomes were identified that have sufficient numbers of parsimony informative sites as to recover the major clades seen in the complete plastome tree. Instead of generating complete plastome sequences, our study showed that accD alone or the concatenation of accD and rbcL can be used in future studies to facilitate identification of Taxillus samples and to generate a molecular phylogeny with robust sampling within the genus.
Topics: DNA, Ribosomal; Evolution, Molecular; Genome, Plastid; Loranthaceae; Mitochondria; NADH Dehydrogenase; Phylogeny; Plastids; RNA, Transfer; Ribosomal Proteins
PubMed: 34407123
DOI: 10.1371/journal.pone.0256345 -
Proceedings of the National Academy of... Jun 2022The evolution of eukaryotic life was predicated on the development of organelles such as mitochondria and plastids. During this complex process of organellogenesis, the...
The evolution of eukaryotic life was predicated on the development of organelles such as mitochondria and plastids. During this complex process of organellogenesis, the host cell and the engulfed prokaryote became genetically codependent, with the integration of genes from the endosymbiont into the host nuclear genome and subsequent gene loss from the endosymbiont. This process required that horizontally transferred genes become active and properly regulated despite inherent differences in genetic features between donor (endosymbiont) and recipient (host). Although this genetic reorganization is considered critical for early stages of organellogenesis, we have little knowledge about the mechanisms governing this process. The photosynthetic amoeba Paulinella micropora offers a unique opportunity to study early evolutionary events associated with organellogenesis and primary endosymbiosis. This amoeba harbors a “chromatophore,” a nascent photosynthetic organelle derived from a relatively recent cyanobacterial association (∼120 million years ago) that is independent of the evolution of primary plastids in plants (initiated ∼1.5 billion years ago). Analysis of the genome and transcriptome of Paulinella revealed that retrotransposition of endosymbiont-derived nuclear genes was critical for their domestication in the host. These retrocopied genes involved in photoprotection in cyanobacteria became expanded gene families and were “rewired,” acquiring light-responsive regulatory elements that function in the host. The establishment of host control of endosymbiont-derived genes likely enabled the cell to withstand photo-oxidative stress generated by oxygenic photosynthesis in the nascent organelle. These results provide insights into the genetic mechanisms and evolutionary pressures that facilitated the metabolic integration of the host–endosymbiont association and sustained the evolution of a photosynthetic organelle.
Topics: Amoeba; Biological Evolution; Eukaryota; Plastids; Rhizaria; Symbiosis
PubMed: 35639693
DOI: 10.1073/pnas.2121241119 -
International Journal of Molecular... May 2021FtsH metalloproteases found in eubacteria, animals, and plants are well-known for their vital role in the maintenance and proteolysis of membrane proteins. Their... (Review)
Review
FtsH metalloproteases found in eubacteria, animals, and plants are well-known for their vital role in the maintenance and proteolysis of membrane proteins. Their location is restricted to organelles of endosymbiotic origin, the chloroplasts, and mitochondria. In the model organism , there are 17 membrane-bound FtsH proteases containing an AAA (ATPase associated with various cellular activities) and a Zn metalloprotease domain. However, in five of those, the zinc-binding motif HEXXH is either mutated (FtsHi1, 2, 4, 5) or completely missing (FtsHi3), rendering these enzymes presumably inactive in proteolysis. Still, homozygous null mutants of the pseudo-proteases FtsHi1, 2, 4, 5 are embryo-lethal. Homozygous or a weak point mutant in are affected in overall plant growth and development. This review will focus on the findings concerning the FtsHi pseudo-proteases and their involvement in protein import, leading to consequences in embryogenesis, seed growth, chloroplast, and leaf development and oxidative stress management.
Topics: Arabidopsis; Arabidopsis Proteins; Chloroplasts; Gene Expression Regulation, Plant; Metalloendopeptidases; Mutation; Protein Transport; Proteolysis; Thylakoids
PubMed: 34072887
DOI: 10.3390/ijms22115917 -
Journal of Experimental Botany Feb 2020The state of etiolation is generally defined by the presence of non-green plastids (etioplasts) in plant tissues that would normally contain chloroplasts. In the... (Review)
Review
The state of etiolation is generally defined by the presence of non-green plastids (etioplasts) in plant tissues that would normally contain chloroplasts. In the commonly used dark-grown seedling system, etiolation is coupled with a type of growth called skotomorphogenesis. Upon illumination, de-etiolation occurs, marked by the transition from etioplast to chloroplast, and, at the seedling level, a switch to photomorphogenic growth. Etiolation and de-etiolation systems are therefore important for understanding both the acquisition of photosynthetic capacity during chloroplast biogenesis and plant responses to light-the most relevant signal in the life and growth of the organism. In this review, we discuss recent discoveries (within the past 2-3 years) in the field of etiolation and de-etiolation, with a particular focus on post-transcriptional processes and ultrastructural changes. We further discuss ambiguities in definitions of the term 'etiolation', and benefits and biases of common etiolation/de-etiolation systems. Finally, we raise several open questions and future research possibilities.
Topics: Chloroplasts; Darkness; Etiolation; Gene Expression Regulation, Plant; Light; Seedlings
PubMed: 31854450
DOI: 10.1093/jxb/erz496 -
Plant Physiology Jul 2020Changes in environmental temperature influence many aspects of plant metabolism; however, the underlying regulatory mechanisms remain poorly understood. In addition to... (Comparative Study)
Comparative Study
Changes in environmental temperature influence many aspects of plant metabolism; however, the underlying regulatory mechanisms remain poorly understood. In addition to their role in light perception, phytochromes (PHYs) have been recently recognized as temperature sensors affecting plant growth. In particular, in Arabidopsis (), high temperature reversibly inactivates PHYB, reducing photomorphogenesis-dependent responses. Here, we show the role of phytochrome-dependent temperature perception in modulating the accumulation of isoprenoid-derived compounds in tomato () leaves and fruits. The growth of tomato plants under contrasting temperature regimes revealed that high temperatures resulted in coordinated up-regulation of chlorophyll catabolic genes, impairment of chloroplast biogenesis, and reduction of carotenoid synthesis in leaves in a PHYB1B2-dependent manner. Furthermore, by assessing a triple mutant and fruit-specific - or -silenced plants, we demonstrated that biosynthesis of the major tomato fruit carotenoid, lycopene, is sensitive to fruit-localized PHY-dependent temperature perception. The collected data provide compelling evidence concerning the impact of PHY-mediated temperature perception on plastid metabolism in both leaves and fruit, specifically on the accumulation of isoprenoid-derived compounds.
Topics: Arabidopsis; Gene Expression Regulation, Plant; Genes, Plant; Hot Temperature; Solanum lycopersicum; Phytochrome; Plastids; Terpenes
PubMed: 32409479
DOI: 10.1104/pp.20.00019 -
The New Phytologist Feb 2020Euglena spp. are phototrophic flagellates with considerable ecological presence and impact. Euglena gracilis harbours secondary green plastids, but an incompletely...
Euglena spp. are phototrophic flagellates with considerable ecological presence and impact. Euglena gracilis harbours secondary green plastids, but an incompletely characterised proteome precludes accurate understanding of both plastid function and evolutionary history. Using subcellular fractionation, an improved sequence database and MS we determined the composition, evolutionary relationships and hence predicted functions of the E. gracilis plastid proteome. We confidently identified 1345 distinct plastid protein groups and found that at least 100 proteins represent horizontal acquisitions from organisms other than green algae or prokaryotes. Metabolic reconstruction confirmed previously studied/predicted enzymes/pathways and provided evidence for multiple unusual features, including uncoupling of carotenoid and phytol metabolism, a limited role in amino acid metabolism, and dual sets of the SUF pathway for FeS cluster assembly, one of which was acquired by lateral gene transfer from Chlamydiae. Plastid paralogues of trafficking-associated proteins potentially mediating fusion of transport vesicles with the outermost plastid membrane were identified, together with derlin-related proteins, potential translocases across the middle membrane, and an extremely simplified TIC complex. The Euglena plastid, as the product of many genomes, combines novel and conserved features of metabolism and transport.
Topics: Biological Evolution; Euglena gracilis; Gene Expression Regulation; Gene Transfer, Horizontal; Plastids; Proteins; Proteome
PubMed: 31580486
DOI: 10.1111/nph.16237 -
International Journal of Molecular... Jan 2020The transfer of genetic material from the mitochondria and plastid to the nucleus gives rise to nuclear integrants of mitochondrial DNA (NUMTs) and nuclear integrants of... (Review)
Review
The transfer of genetic material from the mitochondria and plastid to the nucleus gives rise to nuclear integrants of mitochondrial DNA (NUMTs) and nuclear integrants of plastid DNA (NUPTs). This frequently occurring DNA transfer is ongoing and has important evolutionary implications. In this review, based on previous studies and the analysis of NUMT/NUPT insertions of more than 200 sequenced plant genomes, we analyzed and summarized the general features of NUMTs/NUPTs and highlighted the genetic consequence of organellar DNA insertions. The statistics of organellar DNA integrants among various plant genomes revealed that organellar DNA-derived sequence content is positively correlated with the nuclear genome size. After integration, the nuclear organellar DNA could undergo different fates, including elimination, mutation, rearrangement, fragmentation, and proliferation. The integrated organellar DNAs play important roles in increasing genetic diversity, promoting gene and genome evolution, and are involved in sex chromosome evolution in dioecious plants. The integrating mechanisms, involving non-homologous end joining at double-strand breaks were also discussed.
Topics: Cell Nucleus; Cell Proliferation; DNA End-Joining Repair; DNA, Chloroplast; DNA, Mitochondrial; Evolution, Molecular; Genome Size; Genome, Plant; Mitochondria; Mutation; Plants; Plastids; Sex Chromosomes
PubMed: 31973163
DOI: 10.3390/ijms21030707