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Physiologia Plantarum 2024Heat stress substantially reduces tomato (Solanum lycopersicum) growth and yield globally, thereby jeopardizing food security. DnaJ proteins, constituents of the heat...
Heat stress substantially reduces tomato (Solanum lycopersicum) growth and yield globally, thereby jeopardizing food security. DnaJ proteins, constituents of the heat shock protein system, protect cells from diverse environmental stresses as HSP-70 molecular co-chaperones. In this study, we demonstrated that AdDjSKI, a serine-rich DnaJ III protein induced by pathogens, plays an important role in stabilizing photosystem II (PSII) in response to heat stress. Our results revealed that transplastomic tomato plants expressing the AdDjSKI gene exhibited increased levels of total soluble proteins, improved growth and chlorophyll content, reduced malondialdehyde (MDA) accumulation, and diminished PSII photoinhibition under elevated temperatures when compared with wild-type (WT) plants. Intriguingly, these transplastomic plants maintained higher levels of D1 protein under elevated temperatures compared with the WT plants, suggesting that overexpression of AdDjSKI in plastids is crucial for PSII protection, likely due to its chaperone activity. Furthermore, the transplastomic plants displayed lower accumulation of superoxide radical (O ) and HO, in comparison with the WT plants, plausibly attributed to higher superoxide dismutase (SOD) and ascorbate peroxidase (APX) activities. This also coincides with an enhanced expression of corresponding genes, including SlCuZnSOD, SlFeSOD, SlAPX2, and SltAPX, under heat stress. Taken together, our findings reveal that chloroplastic expression of AdDjSKI in tomatoes plays a critical role in fruit yield, primarily through a combination of delayed senescence and stabilizing PSII under heat stress.
Topics: Solanum lycopersicum; Photosystem II Protein Complex; Heat-Shock Response; Fruit; Plant Proteins; Plant Leaves; Plastids; Chlorophyll; HSP40 Heat-Shock Proteins; Plants, Genetically Modified; Plant Senescence; Gene Expression Regulation, Plant; Malondialdehyde
PubMed: 38837422
DOI: 10.1111/ppl.14374 -
Molecular Plant Jul 2024
Topics: Animals; RNA Interference; Levivirus; Disease Resistance; Plastids; Genetic Engineering; Plant Diseases; Gossypium
PubMed: 38835168
DOI: 10.1016/j.molp.2024.05.013 -
Plant Physiology Jun 2024Plastids in vascular plants have various differentiated forms, among which amyloplasts are crucial for starch storage and plant productivity. Despite the vast knowledge...
Plastids in vascular plants have various differentiated forms, among which amyloplasts are crucial for starch storage and plant productivity. Despite the vast knowledge of the binary-fission mode of chloroplast division, our understanding of the replication of non-photosynthetic plastids, including amyloplasts, remains limited. Recent studies have suggested the involvement of stromules (stroma-filled tubules) in plastid replication when the division apparatus is faulty. However, details of the underlying mechanism(s) and their relevance to normal processes have yet to be elucidated. Here, we developed a live analysis system for studying amyloplast replication using Arabidopsis (Arabidopsis thaliana) ovule integuments. We showed the full sequence of amyloplast development and demonstrated that wild-type amyloplasts adopt three modes of replication, binary fission, multiple fission, and stromule-mediated fission, via multi-way placement of the FtsZ ring. The minE mutant, with severely inhibited chloroplast division, showed marked heterogeneity in amyloplast size, caused by size-dependent but wild-type modes of plastid fission. The dynamic properties of stromules distinguish the wild-type and minE phenotypes. In minE cells, extended stromules from giant amyloplasts acquired stability, allowing FtsZ ring assembly and constriction, as well as the growth of starch grains therein. Despite hyper-stromule formation, amyloplasts did not proliferate in the ftsZ null mutant. These data clarify the differences between amyloplast and chloroplast replication and demonstrate that the structural plasticity of amyloplasts underlies the multiplicity of their replication processes. Furthermore, this study shows that stromules can generate daughter plastids via assembly of the FtsZ ring.
PubMed: 38829834
DOI: 10.1093/plphys/kiae314 -
Planta Jun 2024Significant past, present, and potential future research into the organellar (plastid and mitochondrial) genomes of gymnosperms that can provide insight into the unknown... (Review)
Review
Significant past, present, and potential future research into the organellar (plastid and mitochondrial) genomes of gymnosperms that can provide insight into the unknown origin and evolution of plants is highlighted. Gymnosperms are vascular seed plants that predominated the ancient world before their sister clade, angiosperms, took over during the Late Cretaceous. The divergence of gymnosperms and angiosperms took place around 300 Mya, with the latter evolving into the diverse group of flowering plants that dominate the plant kingdom today. Although gymnosperms have reportedly made some evolutionary innovations, the literature on their genome advances, particularly their organellar (plastid and mitochondrial) genomes, is relatively scattered and fragmented. While organellar genomes can shed light on plant origin and evolution, they are frequently overlooked, due in part to their limited contribution to gene expression and lack of evolutionary dynamics when compared to nuclear genomes. A better understanding of gymnosperm organellar genomes is critical because they reveal genetic changes that have contributed to their unique adaptations and ecological success, potentially aiding in plant survival, enhancement, and biodiversity conservation in the face of climate change. This review reveals significant information and gaps in the existing knowledge base of organellar genomes in gymnosperms, as well as the challenges and research needed to unravel their complexity.
Topics: Cycadopsida; Genome, Plant; Genome, Mitochondrial; Genome, Plastid; Evolution, Molecular; Phylogeny; Biological Evolution
PubMed: 38829418
DOI: 10.1007/s00425-024-04449-4 -
Physiologia Plantarum 2024High temperature (HT) affects the production of chlorophyll (Chl) pigment and inhibits cellular processes that impair photosynthesis, and growth and development in...
High temperature (HT) affects the production of chlorophyll (Chl) pigment and inhibits cellular processes that impair photosynthesis, and growth and development in plants. However, the molecular mechanisms underlying heat stress in rice are not fully understood yet. In this study, we identified two mutants varying in leaf color from the ethylmethanesulfonate mutant library of indica rice cv. Zhongjiazao-17, which showed pale-green leaf color and variegated leaf phenotype under HT conditions. Mut-map revealed that both mutants were allelic, and their phenotype was controlled by a single recessive gene PALE GREEN LEAF 10 (PGL10) that encodes NADPH:protochlorophyllide oxidoreductase B, which is required for the reduction of protochlorophyllide into chlorophyllide in light-dependent tetrapyrrole biosynthetic pathway-based Chl synthesis. Overexpression-based complementation and CRISPR/Cas9-based knockout analyses confirmed the results of Mut-map. Moreover, qRT-PCR-based expression analysis of PGL10 showed that it expresses in almost all plant parts with the lowest expression in root, followed by seed, third leaf, and then other green tissues in both mutants, pgl10a and pgl10b. Its protein localizes in chloroplasts, and the first 17 amino acids from N-terminus are responsible for signals in chloroplasts. Moreover, transcriptome analysis performed under HT conditions revealed that the genes involved in the Chl biosynthesis and degradation, photosynthesis, and reactive oxygen species detoxification were differentially expressed in mutants compared to WT. Thus, these results indicate that PGL10 is required for maintaining chloroplast function and plays an important role in rice adaptation to HT stress conditions by controlling photosynthetic activity.
Topics: Oryza; Photosynthesis; Plant Proteins; Gene Expression Regulation, Plant; Chloroplasts; Hot Temperature; Plant Leaves; Chlorophyll; Mutation; Heat-Shock Response; Loss of Function Mutation; Phenotype; Oxidoreductases Acting on CH-CH Group Donors
PubMed: 38828612
DOI: 10.1111/ppl.14369 -
Advances in Microbial Physiology 2024Organelles are membrane bound structures that compartmentalize biochemical and molecular functions. With improved molecular, biochemical and microscopy tools the... (Review)
Review
Organelles are membrane bound structures that compartmentalize biochemical and molecular functions. With improved molecular, biochemical and microscopy tools the diversity and function of protistan organelles has increased in recent years, providing a complex panoply of structure/function relationships. This is particularly noticeable with the description of hydrogenosomes, and the diverse array of structures that followed, having hybrid hydrogenosome/mitochondria attributes. These diverse organelles have lost the major, at one time, definitive components of the mitochondrion (tricarboxylic cycle enzymes and cytochromes), however they all contain the machinery for the assembly of Fe-S clusters, which is the single unifying feature they share. The plasticity of organelles, like the mitochondrion, is therefore evident from its ability to lose its identity as an aerobic energy generating powerhouse while retaining key ancestral functions common to both aerobes and anaerobes. It is interesting to note that the apicoplast, a non-photosynthetic plastid that is present in all apicomplexan protozoa, apart from Cryptosporidium and possibly the gregarines, is also the site of Fe-S cluster assembly proteins. It turns out that in Cryptosporidium proteins involved in Fe-S cluster biosynthesis are localized in the mitochondrial remnant organelle termed the mitosome. Hence, different organisms have solved the same problem of packaging a life-requiring set of reactions in different ways, using different ancestral organelles, discarding what is not needed and keeping what is essential. Don't judge an organelle by its cover, more by the things it does, and always be prepared for surprises.
Topics: Organelles; Mitochondria; Eukaryota; Iron-Sulfur Proteins
PubMed: 38821633
DOI: 10.1016/bs.ampbs.2024.02.001 -
Current Biology : CB Jun 2024Apicomplexans are obligate intracellular parasites that have evolved from a free-living, phototrophic ancestor. They have been reported from marine environmental samples...
Apicomplexans are obligate intracellular parasites that have evolved from a free-living, phototrophic ancestor. They have been reported from marine environmental samples in high numbers, with several clades of apicomplexan-related lineages (ARLs) having been described from environmental sequencing data (16S rRNA gene metabarcoding). The most notable of these are the corallicolids (previously ARL-V), which possess chlorophyll-biosynthesis genes in their relic chloroplast (apicoplast) and are geographically widespread and abundant symbionts of anthozoans. Corallicolids are related to the Eimeriorina, a suborder of apicomplexan coccidians that include other notable members such as Toxoplasma gondii.Ophioblennius macclurei, the redlip blenny, along with other tropical reef fishes, is known to be infected by Haemogregarina-like and Haemohormidium-like parasites supposedly belonging to the Adeleorina; however, phylogenetics shows that these parasites are instead related to the Eimeriorina. Hybrid genomic sequencing of apicomplexan-infected O. macclurei blood recovered the entire rRNA operon of this apicomplexan parasite along with the complete mitochondrion and apicoplast genomes. Phylogenetic analyses using this new genomic information consistently place these fish-infecting apicomplexans, hereby informally named ichthyocolids, sister to the corallicolids within Coccidia. The apicoplast genome did not contain chlorophyll biosynthesis genes, providing evidence for another independent loss of this pathway within Apicomplexa. Based on the 16S rRNA gene found in the apicoplast, this group corresponds to the previously described ARL-VI. Screening of fish microbiome studies using the plastid 16S rRNA gene shows these parasites to be geographically and taxonomically widespread in fish species across the globe with implications for commercial fisheries and oceanic food webs.
Topics: Animals; Apicomplexa; Phylogeny; Fishes; Fish Diseases
PubMed: 38821048
DOI: 10.1016/j.cub.2024.04.084 -
Physiologia Plantarum 2024With climate change, droughts are expected to be more frequent and severe, severely impacting plant biomass and quality. Here, we show that overexpressing the...
With climate change, droughts are expected to be more frequent and severe, severely impacting plant biomass and quality. Here, we show that overexpressing the Arabidopsis gene AtFtsHi3 (FtsHi3OE) enhances drought-tolerant phenotypes without compromising plant growth. AtFtsHi3 encodes a chloroplast envelope pseudo-protease; knock-down mutants (ftshi3-1) are found to be drought tolerant but exhibit stunted growth. Altered AtFtsHi3 expression therefore leads to drought tolerance, while only diminished expression of this gene leads to growth retardation. To understand the underlying mechanisms of the enhanced drought tolerance, we compared the proteomes of ftshi3-1 and pFtsHi3-FtsHi3OE (pFtsHi3-OE) to wild-type plants under well-watered and drought conditions. Drought-related processes like osmotic stress, water transport, and abscisic acid response were enriched in pFtsHi3-OE and ftshi3-1 mutants following their enhanced drought response compared to wild-type. The knock-down mutant ftshi3-1 showed an increased abundance of HSP90, HSP93, and TIC110 proteins, hinting at a potential downstream role of AtFtsHi3 in chloroplast pre-protein import. Mathematical modeling was performed to understand how variation in the transcript abundance of AtFtsHi3 can, on the one hand, lead to drought tolerance in both overexpression and knock-down lines, yet, on the other hand, affect plant growth so differently. The results led us to hypothesize that AtFtsHi3 may form complexes with at least two other protease subunits, either as homo- or heteromeric structures. Enriched amounts of AtFtsH7/9, AtFtsH11, AtFtsH12, and AtFtsHi4 in ftshi3-1 suggest a possible compensation mechanism for these proteases in the hexamer.
Topics: Arabidopsis; Droughts; Arabidopsis Proteins; Gene Expression Regulation, Plant; Chloroplasts; Plants, Genetically Modified; Plastids; Drought Resistance
PubMed: 38818570
DOI: 10.1111/ppl.14370 -
MLife Dec 2023Photosynthetic microalgae like hold enormous potential as sustainable, light-driven biofactories for the production of high-value natural products such as terpenoids....
Photosynthetic microalgae like hold enormous potential as sustainable, light-driven biofactories for the production of high-value natural products such as terpenoids. is distinguished as a particularly robust host with extensive genomic and transgenic resources available. Its capacity to grow in wastewater, brackish, and sea waters, coupled with advances in microalgal metabolic engineering, genome editing, and synthetic biology, provides an excellent opportunity. In the present work, we demonstrate how can be engineered to produce the diterpene casbene-an important intermediate in the biosynthesis of pharmacologically relevant macrocyclic diterpenoids. Casbene accumulated after stably expressing and targeting the casbene synthase from (DgTPS1) to the algal chloroplast. The engineered strains yielded production titers of up to 0.12 mg g total dry cell weight (DCW) casbene. Heterologous overexpression and chloroplast targeting of two upstream rate-limiting enzymes in the 2-C-methyl- d-erythritol 4-phosphate pathway, 1-deoxy- d-xylulose-5-phosphate synthase and geranylgeranyl diphosphate synthase genes, further enhanced the yield of casbene to a titer up to 1.80 mg g DCW. The results presented here form a basis for further development and production of complex plant diterpenoids in microalgae.
PubMed: 38818264
DOI: 10.1002/mlf2.12097 -
BMC Genomic Data May 2024Oreomecon nudicaulis, commonly known as mountain poppy, is a significant perennial herb. In 2022, the species O. nudicaulis, which was previously classified under the...
Oreomecon nudicaulis, commonly known as mountain poppy, is a significant perennial herb. In 2022, the species O. nudicaulis, which was previously classified under the genus Papaver, was reclassified within the genus Oreomecon. Nevertheless, the phylogenetic status and chloroplast genome within the genus Oreomecon have not yet been reported. This study elucidates the chloroplast genome sequence and structural features of O. nudicaulis and explores its evolutionary relationships within Papaveraceae. Using Illumina sequencing technology, the chloroplast genome of O. nudicaulis was sequenced, assembled, and annotated. The results indicate that the chloroplast genome of O. nudicaulis exhibits a typical circular quadripartite structure. The chloroplast genome is 153,903 bp in length, with a GC content of 38.87%, containing 84 protein-coding genes, 8 rRNA genes, 38 tRNA genes, and 2 pseudogenes. The genome encodes 25,815 codons, with leucine (Leu) being the most abundant codon, and the most frequently used codon is AUU. Additionally, 129 microsatellite markers were identified, with mononucleotide repeats being the most abundant (53.49%). Our phylogenetic analysis revealed that O. nudicaulis has a relatively close relationship with the genus Meconopsis within the Papaveraceae family. The phylogenetic analysis supported the taxonomic status of O. nudicaulis, as it did not form a clade with other Papaver species, consistent with the revised taxonomy of Papaveraceae. This is the first report of a phylogenomic study of the complete chloroplast genome in the genus Oreomecon, which is a significant genus worldwide. This analysis of the O. nudicaulis chloroplast genome provides a theoretical basis for research on genetic diversity, molecular marker development, and species identification, enriching genetic information and supporting the evolutionary relationships among Papaveraceae.
Topics: Phylogeny; Genome, Chloroplast; Genomics; Papaveraceae; Microsatellite Repeats; Chloroplasts; Base Composition; Evolution, Molecular; RNA, Transfer
PubMed: 38816818
DOI: 10.1186/s12863-024-01236-8