The changes of chlorophyll_protein complexes and photosynthetic activities of chloroplast isolated from lotus ( Nelumbo nucifera Gaertn.) seeds germinating under illumination were studied. SDS PAGE analysis of c...The changes of chlorophyll_protein complexes and photosynthetic activities of chloroplast isolated from lotus ( Nelumbo nucifera Gaertn.) seeds germinating under illumination were studied. SDS PAGE analysis of chlorophyll_protein complexes showed that there was only the light harvesting chlorophyll a/b protein complex from PSⅡ (LHCⅡ) precursor in chloroplast from lotus seeds germinated for 2 to 6 days, while LHC Ⅱ 1, and the chlorophyll_protein complex of PSⅠ (CPⅠ) appeared on the 8th day of germination and PSⅡ reaction center complex appeared later. Studies on the polypeptides composition of the chloroplast revealed the following results: 1) Small amount of the 27 kD polypeptide was synthesized in invisible light; 2) The 30 kD polypeptide existed previously in the plumules of the dry seeds; 3) The amount of the 30 kD polypeptide was more than any other polypeptides before germination and decreased gradually throughout germination, while the 27 kD polypeptide changed in the opposite way; 4) In the process of germination, measurement of the electron transport rate and the fluorescence induction kinetics at room temperature showed that PSⅡ activities and efficiency of primary light energy transformation were only experimentally measurable after 7 days of germination and gradually increased afterwards. At the same time, the chl a/b ratio rose from the lower value to normal; 5) The changes of chloroplast membrane components and its functions are concomitant in concert with that of the ultrastructure of chloroplast membranes during germination, as shown in our earlier work . The results have proved again that a different developmental pathway of chloroplast is likely to exist in the lotus plumules, which might provide an important clue for N. nucifera in having an unique position in the phylogeny of the angiosperm.展开更多
Wheat ( Triticum aestivum L.) plants were grown under ambient and doubled_CO 2(plus 350 μL/L) concentration in cylindrical open_top chamber to examine their effects on the ultrastructure, supramolecular architect...Wheat ( Triticum aestivum L.) plants were grown under ambient and doubled_CO 2(plus 350 μL/L) concentration in cylindrical open_top chamber to examine their effects on the ultrastructure, supramolecular architecture, absorption spectrum and low temperature (77 K) fluorescence emission spectrum of the chloroplasts from wheat leaves. The results were briefly summarized as follows: (1) The wheat leaves possessed normally developed chloroplasts with intact grana and stroma thylakoid membranes; The grana intertwined with stroma thylakoid membranes and increased slightly in stacking degree and the width of granum, in spite of more accumulated starch grains within the chloroplasts than those in control; (2) The particle density in the stacked region of the endoplasmic fracture face (EFs) and protoplasmic fracture face (PFs) and in the unstacked region the endoplasmic fracture face (EFu) and the protoplasmic fracture face (PFu) was significantly higher than that of control. Furthermore, in some cases many more particles on EFs faces of thylakoid membranes appeared as a paracrystalline particle array; (3) The variations in the structure of chloroplasts were consistent with the absorption spectra and the low temperature (77 K) fluorescence emission spectra of the chloroplasts developed under the doubled_CO 2 concentration. Results indicate that the capability of light energy absorption of chloroplasts and regulative capability of excitation energy distribution between PSⅡ and PSⅠ were raised by doubled_CO 2 concentration. This is very favorable for final productivity of wheat.展开更多
Linolenic acid has great effects on the structure and function of chloroplast. We studied the effects of Ce3＋ on the improvement of chloroplast spectral characteristics and oxygen evolution damaged by linolenic acid ...Linolenic acid has great effects on the structure and function of chloroplast. We studied the effects of Ce3＋ on the improvement of chloroplast spectral characteristics and oxygen evolution damaged by linolenic acid in spinach. Results showed that Ce3＋ could decrease the light absorption increased by linolenic acid and promote the distribution of excitation energy to PS II and alleviate the decrease of PS Ⅱ fluo- rescence yield caused by linolenic acid. The linolenic acid treatments in various concentrations reduced the oxygen-evolving rate of chloroplasts, but the rate was accelerated since adding Ce3＋.展开更多
The effects of exogenous GSH（reduced glutathione）on photosynthetic characteristics,photosystem Ⅱ efficiency,absorbed light energy allocation and the H2O2-scavenging system in chloroplasts of salt-stressed tomato（S...The effects of exogenous GSH（reduced glutathione）on photosynthetic characteristics,photosystem Ⅱ efficiency,absorbed light energy allocation and the H2O2-scavenging system in chloroplasts of salt-stressed tomato（Solanum lycopersicum L.）seedlings were studied using hydroponic experiments in a greenhouse.Application of exogenous GSH ameliorated saline-induced growth inhibition,the disturbed balance of Na＋ and Cl- ions and Na＋/K＋ ratios,and the reduction of the net photosynthetic rate（Pn）.GSH also increased the maximal photochemical efficiency of PSⅡ（Fv/Fm）,the electron transport rate（ETR）,the photochemical quenching coefficient（qP）,and the non-photochemical quenching coefficient（NPQ）.In addition,GSH application increased the photochemical quantum yield（Y（Ⅱ））and relative deviation from full balance between the photosystems（β/α-1）and decreased the PSⅡ excitation pressure（1-qP）and quantum yield of non-regulated energy dissipation（Y（NO））in leaves of salt-stressed tomatoes without BSO（L-buthionine-sulfoximine,an inhibitor of key GSH synthesis enzymeγ-glutamylcysteine synthetase）or with BSO.Further,the addition of GSH depressed the accumulation of H2O2 and malondialdehyde（MDA）,induced the redistribution of absorbed light energy in PSⅡ reaction centers,and improved the endogenous GSH content,GSH/GSSH ratio and activities of H2O2-scavenging enzymes（including superoxidase dismutase（SOD）,catalase（CAT）,peroxidase（POD）and key enzymes in the AsA-GSH cycle and Grx system）in the chloroplasts of salt-stressed plants with or without BSO.Therefore,GSH application alleviates inhibition of salt-induced growth and photosynthesis mainly by overcoming stomatal limitations,improving the PSⅡ efficiency,and balancing the uneven distribution of light energy to reduce the risk of ROS generation and to mediate chloroplast redox homeostasis and the antioxidant defense system to protect the chloroplasts from oxidative damage.Thus,GSH may be used as a potential tool for alleviating salt stress in tomato plants.展开更多
Marine microalga Isochrysis galbana is an important feed species with a high nutritional value.Different from other uni-cellular algae,its cell contains two chloroplasts which are the major sites for lipid synthesis.H...Marine microalga Isochrysis galbana is an important feed species with a high nutritional value.Different from other uni-cellular algae,its cell contains two chloroplasts which are the major sites for lipid synthesis.Here,we optimized a chloroplast isola-tion approach suitable for the isolation of I.galbana chloroplasts and determined the purity and integrity of the isolated chloroplasts through microscopic observations and enzyme activity assay.The chloroplast lipids were analyzed with a ultrahigh-performance li-quid chromatography-Q Exactive Orbitrap-mass spectrometry.This newly developed isolation approach is simple and reliable to isolate chloroplasts with high integrity and purity.The average yield of intact chloroplasts was 15.3%±0.1%.Glycolipids and acyl-glycerols were the main chloroplast lipids.Glycolipids accounted for 56.6%of chloroplast lipid.Digalactosyldiacylglycerol(DGDG),monogalactosyldiacylglycerol(MGDG)and sulfoquinovosyldiacylglycerol(SQDG)were the main glyceroglycolipids.The fatty acyl R1/R2 were mostly 18:4/16:1,18:3/16:1 and 18:4/18:5 in DGDGs,14:0/18:4,18:4/18:5,18:4/18:4 and 18:3/18:4 in MGDGs and 16:0/14:0,16:0/18:3,and 18:4/18:3 in SQDGs.In addition,diacylglycerol(DAG)was the most abundant acylglycerols;the content of 22:6/18:4-DAG was the highest.There was a little amount of glycosphingolipid(GSL)in chloroplast.Digalactosylmonoglyceride(DGMG),monogalactosylmonoglyceride(MGMG),sulfoquinovosylmonoacylglycerol(SQMG),monoglyceride(MAG),phospholi-pids(PLs),ceramide(Cer)and betaine lipids were nearly undetectable in chloroplast.The fatty acid proportions of DGDGs,MGDGs,SQDGs,DAGs,triglycerides(TAGs)and GSLs were either higher or lower than or similar to those of whole-cell.Collectively,our isolation approach is applicable to many aspects of chloroplast biology,and may offer a reference for the isolation of chloroplasts from other marine microalgae.展开更多
Unicellular micro-alga Chlamydomonas reinhardtii has been recognized as a promising host for expressing recombinant proteins albeit its limited utility due to low levels of heterologous protein expression. Here, trans...Unicellular micro-alga Chlamydomonas reinhardtii has been recognized as a promising host for expressing recombinant proteins albeit its limited utility due to low levels of heterologous protein expression. Here, transcription of the 3.4-kb mosquito-larvicidal cry4Ba gene from Bacillus thuringiensis in transgenic C. reinhardtii chloroplasts under control of the promoter and 5’-untranslated region of photosynthetic psbA gene was accomplished. Inverted repeats in chloroplast genomes of the host strain with deleted endogenous psbA genes were selected as recombination targets. Two transformant lines were obtained by dual-phenotypic screening via exhibition of resistance to spectinomycin and restoration of photosynthetic activity. Stable and site-specific integration of intact cry4Ba and psbA genes into chloroplast genomes found in both transgenic lines implied homoplasmy of organelle populations. Achievement in cotranscription of cry4Ba and psbA transgenes revealed by RT-PCR and Northern blot analyses demonstrates the sufficiency of this system’s transcription machinery, offering the further innovation for insecticidal protein production.展开更多
The chloroplast and mitochondrion of brown algae （Class Phaeophyceae of Phylum Ochrophyta） may have originated from different endosymbiosis. In this study, we carried out phylogenomic analysis to distinguish their e...The chloroplast and mitochondrion of brown algae （Class Phaeophyceae of Phylum Ochrophyta） may have originated from different endosymbiosis. In this study, we carried out phylogenomic analysis to distinguish their evolutionary lineages by using algal RNA-seq datasets of the 1 000 Plants （1KP） Project and publicly available complete genomes of mitochondria and chloroplasts of Kingdom Chromista. We have found that there is a split between Class Phaeophyceae of Phylum Ochrophyta and the others （Phylum Cryptophyta and Haptophyta） in Kingdom Chromista, and identified more diversity in chloroplast genes than mitochondrial ones in their phylogenetic trees. Taxonomy resolution for Class Phaeophyceae showed that it was divided into Laminariales-Ectocarpales clade and Fucales clade, and phylogenetic positions of Kjellmaniella crassi-folia, Hizikia fusifrome and Ishige okamurai were confirmed. Our analysis provided the basic phylogenetic relationships of Chromista algae, and demonstrated their potential ability to study endosymbiotic events.展开更多
The chloroplast and mitochondrion of red algae （Phylum Rhodophyta） may have originated from different endosymbiosis. In this study, we carried out phylogenomic analysis to distinguish their evolutionary lin-eages by...The chloroplast and mitochondrion of red algae （Phylum Rhodophyta） may have originated from different endosymbiosis. In this study, we carried out phylogenomic analysis to distinguish their evolutionary lin-eages by using red algal RNA-seq datasets of the 1 000 Plants （1KP） Project and publicly available complete genomes of mitochondria and chloroplasts of Rhodophyta. We have found that red algae were divided into three clades of orders, Florideophyceae, Bangiophyceae and Cyanidiophyceae. Taxonomy resolution for Class Florideophyceae showed that Order Gigartinales was close to Order Halymeniales, while Order Graci-lariales was in a clade of Order Ceramials. We confirmed Prionitis divaricata （Family Halymeniaceae） was closely related to the clade of Order Gracilariales, rather than to genus Grateloupia of Order Halymeniales as reported before. Furthermore, we found both mitochondrial and chloroplastic genes in Rhodophyta under negative selection （Ka/Ks〈1）, suggesting that red algae, as one primitive group of eukaryotic algae, might share joint evolutionary history with these two organelles for a long time, although we identified some dif-ferences in their phylogenetic trees. Our analysis provided the basic phylogenetic relationships of red algae, and demonstrated their potential ability to study endosymbiotic events.展开更多
Wang G,Hong M,Yang C,et al.Biomimetic chloroplasts:Two-phase microfluidic platforms with selective permeability for artificial photosynthesis.Droplet.2025;4(4):e70019.https://doi.org/10.1002/dro2.70019 The correspondi...Wang G,Hong M,Yang C,et al.Biomimetic chloroplasts:Two-phase microfluidic platforms with selective permeability for artificial photosynthesis.Droplet.2025;4(4):e70019.https://doi.org/10.1002/dro2.70019 The corresponding author information in the published version was incomplete due to an oversight during submission.The correct corresponding authors are.展开更多
The development of biomimetic chloroplasts offers significant potential in addressing global energy and environmental challenges.Traditional droplet-based models are limited by transmembrane transport inefficiencies,l...The development of biomimetic chloroplasts offers significant potential in addressing global energy and environmental challenges.Traditional droplet-based models are limited by transmembrane transport inefficiencies,leading to the accumulation of aqueous products that severely hinder reaction performance.In this work,we present a biomimetic chloroplast system that integrates light-dependent and lightindependent reactions,reaction compartments,and selectively permeable interfaces,fabricated using a biphasic microfluidic platform.The permeable interface facilitates continuous substrate–product exchange,mitigating product inhibition and side reactions,thus enhancing reaction efficiency.Furthermore,a quartz spiral tube was engineered to amplify Dean vortex effects,improving mass transfer.This system exhibited a nicotinamide adenine dinucleotide regeneration efficiency during lightdependent reactions that was 5.52 times higher than that of conventional slurry reactors.In the light-independent reaction,the energy conversion efficiency for the transformation ofα-ketoglutaric acid to L-glutamic acid reached 1.45 times that of natural photosynthesis.As the first comprehensive integration of photosynthetic processes within artificial chloroplasts,this work combines biological mechanisms with engineered components to establish a transformative platform for efficient energy conversion and directional biosynthesis.This breakthrough advances the field of photocatalysis and bioinspired technologies,with wide-reaching implications for sustainable energy and synthetic biology applications.展开更多
In nature,plants are under attack by a range of pathogens.To cope with these pathogens,plants have evolved a sophisticated immune system,including pattern-triggered immunity(PTI)initiated by pattern recognition recept...In nature,plants are under attack by a range of pathogens.To cope with these pathogens,plants have evolved a sophisticated immune system,including pattern-triggered immunity(PTI)initiated by pattern recognition receptors on the cell surface and effector-triggered immunity(ETI)activated by intracellular nucleotide-binding and leucine-rich repeat receptors.In recent years,increasing evidence has demonstrated that organelles such as the chloroplast play crucial roles in complete activation of plant immunity.In this review,we focus on the chloroplast and summarize its role in regulating the activation of immune events,including influx of calcium(Ca^(2+)),accumulation of reactive oxygen species(ROS),biosynthesis of phytohormones,and expression of defense-related genes.Because information exchange between the chloroplast and the nucleus is very important during plant immunity,we also highlight the importance of chloroplast-nucleus communication via stromules in plant immunity.This review reveals the function of the chloroplast in maintaining the trade-off between plant growth and immunity,and expands our understanding of how chloroplasts enable complete activation of plant immunity.展开更多
Iron is an essential nutrient for plant metabolism such that Fe-limited plants display chlorosis and suffer from reduced photosynthetic efficiency.Differential display previously identified genes whose expression was ...Iron is an essential nutrient for plant metabolism such that Fe-limited plants display chlorosis and suffer from reduced photosynthetic efficiency.Differential display previously identified genes whose expression was elevated in Fe-deficient maize roots.Here,we describe the functional characterization of one of the genes identified in the screen,ZmFDR3(Zea maize Fe-deficiency-related).Heterologous functional complementation assays using a yeast iron uptake mutant showed that ZmFDR3 functions in iron transport.ZmFDR3 contains a domain found in FliN-proteins of the type III secretion system and is predicted to localize to the thylakoid of plastids.Fluorescence immunocytochemistry showed that ZmFDR3 is localized in the plastids of roots,stems and leaves,with high expression found in guard cell chloroplasts.Transgenic tobacco expressing a 35S-ZmFDR3 construct contains elevated iron content,displays well arranged thylakoid membranes and has photosynthetic indices that are higher than those of the wild type.Together,these results suggest that ZmFDR3 functions in chloroplast iron transport.展开更多
Recent technical advances in electrophysiological measurements, organelle-targeted fluorescence imaging, and organelle proteomics have pushed the research of ion transport a step forward in the case of the plant bioen...Recent technical advances in electrophysiological measurements, organelle-targeted fluorescence imaging, and organelle proteomics have pushed the research of ion transport a step forward in the case of the plant bioenergetic organelles, chloroplasts and mitochondria, leading to the molecular identification and functional characterization of several ion transport systems in recent years. Here we focus on channels that mediate relatively high-rate ion and water flux and summarize the current knowledge in this field, focusing on targeting mechanisms, proteomics, electrophysiology, and physiological function. In addition, since chloroplasts evolved from a cyanobacterial ancestor, we give an overview of the information available about cyanobacterial ion channels and discuss the evolutionary origin of chloroplast channels. The recent molecular identification of some of these ion channels allowed their physiological functions to be studied using genetically modified Arabidopsis plants and cyanobacteria. The view is emerging that alteration of chloroplast and mitochondrial ion homeostasis leads to organelle dysfunction, which in turn significantly affects the energy metabolism of the whole organism. Clear-cut identification of genes encoding for chan- nels in these organelles, however, remains a major challenge in this rapidly developing field. Multiple stra- tegies including bioinformatics, cell biology, electrophysiology, use of organelle-targeted ion-sensitive probes, genetics, and identification of signals eliciting specific ion fluxes across organelle membranes should provide a better understanding of the physiological role of organellar channels and their contribution to signaling pathways in plants in the future.展开更多
Protein translocation across membranes is a fundamental cellular process. The majority of the proteins of organelles such as mitochondria and chloroplasts is synthesized in the cytosol and subsequently imported in a p...Protein translocation across membranes is a fundamental cellular process. The majority of the proteins of organelles such as mitochondria and chloroplasts is synthesized in the cytosol and subsequently imported in a posttranslational manner. The precursor proteins have to be unfolded at least for translocation, but it has also been assumed that they are unfolded during transport to the organelle in the cytosol. Unfolding is governed by chaperones and the translocon itself. At the same time, chaperones provide the energy for the import process. The energetic properties of the chloroplast translocon were studied by import of the Ig-like module of the muscle protein titin fused to the transit peptide of the chloroplast targeted oxygen evolving complex subunit of 33 kDa （OE33）. Our results suggest that p（OE33）titin is folded prior to import and that translocation is initiated by unfolding after having bound to the translocon at the chloroplast surface. Using a set of stabilizing and destabilizing mutants of titin previously analyzed by atomic force microscopy and as passenger for mitochondrial translocation, we studied the unfolding force provided by the chloroplast translocon. Based on these results, a model for translocation is discussed.展开更多
Plants possess both types of endosymbiotic organelles, chloroplasts and mitochondria. Transit peptides and presequences function as signal sequences for specific import into chloroplasts and mitochondria, respectively...Plants possess both types of endosymbiotic organelles, chloroplasts and mitochondria. Transit peptides and presequences function as signal sequences for specific import into chloroplasts and mitochondria, respectively. However, how these highly similar signal sequences confer the protein import specificity remains elusive. Here, we show that mitochondrial- or chloroplast-specific import involves two distinct steps, specificity determination and translocation across envelopes, which are mediated by the N-terminal regions and functionally interchangeable C-terminal regions, respectively, of transit peptides and presequences. A domain harboring multiple-arginine and hydrophobic sequence motifs in the N-terminal regions of presequences was identified as the mitochondrial specificity factor. The presence of this domain and the absence of arginine residues in the N-terminal regions of otherwise common targeting signals confers specificity of protein import into mitochondria and chloroplasts, respectively. AtToc159, a chloroplast import receptor, also contributes to determining chloroplast import specificity. We propose that common ancestral sequences were functionalized into mitochondrial- and chloroplast-specific signal sequences by the presence and absence, respectively, of multiple-arginine and hydrophobic sequence motifs in the N-terminal region.展开更多
Alkali-salinity exerts severe osmotic,ionic,and high-p H stresses to plants.To understand the alkali-salinity responsive mechanisms underlying photosynthetic modulation and reactive oxygen species(ROS)homeostasis,phys...Alkali-salinity exerts severe osmotic,ionic,and high-p H stresses to plants.To understand the alkali-salinity responsive mechanisms underlying photosynthetic modulation and reactive oxygen species(ROS)homeostasis,physiological and diverse quantitative proteomics analyses of alkaligrass(Puccinellia tenuiflora)under Na_(2)CO_(3)stress were conducted.In addition,Western blot,real-time PCR,and transgenic techniques were applied to validate the proteomic results and test the functions of the Na_(2)CO_(3)-responsive proteins.A total of 104 and 102 Na_(2)CO_(3)-responsive proteins were identified in leaves and chloroplasts,respectively.In addition,84 Na_(2)CO_(3)-responsive phosphoproteins were identified,including 56 new phosphorylation sites in 56 phosphoproteins from chloroplasts,which are crucial for the regulation of photosynthesis,ion transport,signal transduction,and energy homeostasis.A full-length Pt FBA encoding an alkaligrass chloroplastic fructosebisphosphate aldolase(FBA)was overexpressed in wild-type cells of cyanobacterium Synechocystis sp.Strain PCC 6803,leading to enhanced Na_(2)CO_(3)tolerance.All these results indicate that thermal dissipation,state transition,cyclic electron transport,photorespiration,repair of photosystem(PS)Ⅱ,PSI activity,and ROS homeostasis were altered in response to Na_(2)CO_(3)stress,which help to improve our understanding of the Na_(2)CO_(3)-responsive mechanisms in halophytes.展开更多
Chloroplasts and mitochondria are both thought to have arisen through primary endosymbiosis (Kutschera and Niklas, 2005). As each organelle evolved, most of its genome was transferred to the host nucleus resulting in ...Chloroplasts and mitochondria are both thought to have arisen through primary endosymbiosis (Kutschera and Niklas, 2005). As each organelle evolved, most of its genome was transferred to the host nucleus resulting in the vast majority of its proteome being nuclear encoded and synthesized on cytosolic ribosomes (Shi and Theg, 2013).展开更多
Stephanodiscaceae is one of the most diverse family of the freshwater centric diatoms.However,the scarcity of whole plastome data poses a significant challenge to the undertaking of genomic studies on this taxonomic g...Stephanodiscaceae is one of the most diverse family of the freshwater centric diatoms.However,the scarcity of whole plastome data poses a significant challenge to the undertaking of genomic studies on this taxonomic group.We collected data on the plastid genomes from 33 members of the Stephanodiscaceae and its close relatives,including 12 newly-sequenced genomes and 21 deposited in National Center for Biotechnology Information(NCBI).Phylogenetic trees are yielded five major clades based on homologous genes.The features of the plastid genomes,including repeat sequences,codon usage,and selection pressure for each clade,are analyzed.The paper makes a contribution to the field of diatom genomics by describing the structural characteristics of the plastid genomes in the Stephanodiscaceae and its closely related species,complemented by related analyses.It provides crucial data that will serve as indispensable references for future research.展开更多
Genic male sterility(GMS)is critical for heterosis utilization and hybrid seed production.Although GMS mutants and genes have been studied extensively in plants,it has remained unclear whether chloroplast-associated p...Genic male sterility(GMS)is critical for heterosis utilization and hybrid seed production.Although GMS mutants and genes have been studied extensively in plants,it has remained unclear whether chloroplast-associated photosynthetic and metabolic activities are involved in the regulation of anther development.In this study,we characterized the function of ZmMs33/ZmGPAT6,which encodes a member of the glycerol-3-phosphate acyltransferase(GPAT)family that catalyzes the first step of the glycerolipid synthetic pathway.We found that normal structure and function of endothecium(En)chloroplasts maintained by ZmMs33-mediated lipid biosynthesis in tapetal cells are crucial for maize anther development.ZmMs33 is expressed mainly in the tapetum at early anther developmental stages and critical for cell proliferation and expansion at late stages.Chloroplasts in En cells of wild-type anthers function as starch storage sites before stage 10 but as photosynthetic factories since stage 10 to enable starch metabolism and carbohydrate supply.Loss of ZmMs33 function inhibits the biosynthesis of glycolipids and phospholipids,which are major components of En chloroplast membranes,and disrupts the development and function of En chloroplasts,resulting in the formation of abnormal En chloroplasts containing numerous starch granules.Further analyses reveal that starch synthesis during the day and starch degradation at night are greatly suppressed in the mutant anthers,leading to carbon starvation and low energy status,as evidenced by low trehalose-6-phosphate content and a reduced ATP/AMP ratio.The energy sensor and inducer of autophagy,SnRK1,was activated to induce early and excessive autophagy,premature PCD,and metabolic reprogramming in tapetal cells,finally arresting the elongation and development of mutant anthers.Taken together,our results not only show that ZmMs33 is required for normal structure and function of En chloroplasts but also reveal that starch metabolism and photosynthetic activities of En chloroplasts at different developmental stages are essential for normal anther development.These findings provide novel insights for understanding how lipid biosynthesis in the tapetum,the structure and function of En chloroplasts,and energy and substance metabolism are coordinated to maintain maize anther development.展开更多
文摘The changes of chlorophyll_protein complexes and photosynthetic activities of chloroplast isolated from lotus ( Nelumbo nucifera Gaertn.) seeds germinating under illumination were studied. SDS PAGE analysis of chlorophyll_protein complexes showed that there was only the light harvesting chlorophyll a/b protein complex from PSⅡ (LHCⅡ) precursor in chloroplast from lotus seeds germinated for 2 to 6 days, while LHC Ⅱ 1, and the chlorophyll_protein complex of PSⅠ (CPⅠ) appeared on the 8th day of germination and PSⅡ reaction center complex appeared later. Studies on the polypeptides composition of the chloroplast revealed the following results: 1) Small amount of the 27 kD polypeptide was synthesized in invisible light; 2) The 30 kD polypeptide existed previously in the plumules of the dry seeds; 3) The amount of the 30 kD polypeptide was more than any other polypeptides before germination and decreased gradually throughout germination, while the 27 kD polypeptide changed in the opposite way; 4) In the process of germination, measurement of the electron transport rate and the fluorescence induction kinetics at room temperature showed that PSⅡ activities and efficiency of primary light energy transformation were only experimentally measurable after 7 days of germination and gradually increased afterwards. At the same time, the chl a/b ratio rose from the lower value to normal; 5) The changes of chloroplast membrane components and its functions are concomitant in concert with that of the ultrastructure of chloroplast membranes during germination, as shown in our earlier work . The results have proved again that a different developmental pathway of chloroplast is likely to exist in the lotus plumules, which might provide an important clue for N. nucifera in having an unique position in the phylogeny of the angiosperm.
文摘Wheat ( Triticum aestivum L.) plants were grown under ambient and doubled_CO 2(plus 350 μL/L) concentration in cylindrical open_top chamber to examine their effects on the ultrastructure, supramolecular architecture, absorption spectrum and low temperature (77 K) fluorescence emission spectrum of the chloroplasts from wheat leaves. The results were briefly summarized as follows: (1) The wheat leaves possessed normally developed chloroplasts with intact grana and stroma thylakoid membranes; The grana intertwined with stroma thylakoid membranes and increased slightly in stacking degree and the width of granum, in spite of more accumulated starch grains within the chloroplasts than those in control; (2) The particle density in the stacked region of the endoplasmic fracture face (EFs) and protoplasmic fracture face (PFs) and in the unstacked region the endoplasmic fracture face (EFu) and the protoplasmic fracture face (PFu) was significantly higher than that of control. Furthermore, in some cases many more particles on EFs faces of thylakoid membranes appeared as a paracrystalline particle array; (3) The variations in the structure of chloroplasts were consistent with the absorption spectra and the low temperature (77 K) fluorescence emission spectra of the chloroplasts developed under the doubled_CO 2 concentration. Results indicate that the capability of light energy absorption of chloroplasts and regulative capability of excitation energy distribution between PSⅡ and PSⅠ were raised by doubled_CO 2 concentration. This is very favorable for final productivity of wheat.
基金supported by the National Natural Science Foundation of China (30800068)
文摘Linolenic acid has great effects on the structure and function of chloroplast. We studied the effects of Ce3＋ on the improvement of chloroplast spectral characteristics and oxygen evolution damaged by linolenic acid in spinach. Results showed that Ce3＋ could decrease the light absorption increased by linolenic acid and promote the distribution of excitation energy to PS II and alleviate the decrease of PS Ⅱ fluo- rescence yield caused by linolenic acid. The linolenic acid treatments in various concentrations reduced the oxygen-evolving rate of chloroplasts, but the rate was accelerated since adding Ce3＋.
基金funded by the National Natural Science Foundation of China (31360478)the International Cooperation Project of Xinjiang Production and Construction Corps, China (2014BC002)
文摘The effects of exogenous GSH（reduced glutathione）on photosynthetic characteristics,photosystem Ⅱ efficiency,absorbed light energy allocation and the H2O2-scavenging system in chloroplasts of salt-stressed tomato（Solanum lycopersicum L.）seedlings were studied using hydroponic experiments in a greenhouse.Application of exogenous GSH ameliorated saline-induced growth inhibition,the disturbed balance of Na＋ and Cl- ions and Na＋/K＋ ratios,and the reduction of the net photosynthetic rate（Pn）.GSH also increased the maximal photochemical efficiency of PSⅡ（Fv/Fm）,the electron transport rate（ETR）,the photochemical quenching coefficient（qP）,and the non-photochemical quenching coefficient（NPQ）.In addition,GSH application increased the photochemical quantum yield（Y（Ⅱ））and relative deviation from full balance between the photosystems（β/α-1）and decreased the PSⅡ excitation pressure（1-qP）and quantum yield of non-regulated energy dissipation（Y（NO））in leaves of salt-stressed tomatoes without BSO（L-buthionine-sulfoximine,an inhibitor of key GSH synthesis enzymeγ-glutamylcysteine synthetase）or with BSO.Further,the addition of GSH depressed the accumulation of H2O2 and malondialdehyde（MDA）,induced the redistribution of absorbed light energy in PSⅡ reaction centers,and improved the endogenous GSH content,GSH/GSSH ratio and activities of H2O2-scavenging enzymes（including superoxidase dismutase（SOD）,catalase（CAT）,peroxidase（POD）and key enzymes in the AsA-GSH cycle and Grx system）in the chloroplasts of salt-stressed plants with or without BSO.Therefore,GSH application alleviates inhibition of salt-induced growth and photosynthesis mainly by overcoming stomatal limitations,improving the PSⅡ efficiency,and balancing the uneven distribution of light energy to reduce the risk of ROS generation and to mediate chloroplast redox homeostasis and the antioxidant defense system to protect the chloroplasts from oxidative damage.Thus,GSH may be used as a potential tool for alleviating salt stress in tomato plants.
基金supported by the Ningbo Science and Technology Research Projects(No.2019B10006)the Na-tional Key Research and Development Program of China(No.2019YFD0900400)+3 种基金the Zhejiang Major Science Pro-ject(No.2019C02057)the China Agriculture Research System of MOF and MARA,the Natural Science Founda-tion of Ningbo(No.2019A610416)the Ningbo Science and Technology Research Projects(No.2019C10023)the National Natural Science Foundation of China(No.31801724).
文摘Marine microalga Isochrysis galbana is an important feed species with a high nutritional value.Different from other uni-cellular algae,its cell contains two chloroplasts which are the major sites for lipid synthesis.Here,we optimized a chloroplast isola-tion approach suitable for the isolation of I.galbana chloroplasts and determined the purity and integrity of the isolated chloroplasts through microscopic observations and enzyme activity assay.The chloroplast lipids were analyzed with a ultrahigh-performance li-quid chromatography-Q Exactive Orbitrap-mass spectrometry.This newly developed isolation approach is simple and reliable to isolate chloroplasts with high integrity and purity.The average yield of intact chloroplasts was 15.3%±0.1%.Glycolipids and acyl-glycerols were the main chloroplast lipids.Glycolipids accounted for 56.6%of chloroplast lipid.Digalactosyldiacylglycerol(DGDG),monogalactosyldiacylglycerol(MGDG)and sulfoquinovosyldiacylglycerol(SQDG)were the main glyceroglycolipids.The fatty acyl R1/R2 were mostly 18:4/16:1,18:3/16:1 and 18:4/18:5 in DGDGs,14:0/18:4,18:4/18:5,18:4/18:4 and 18:3/18:4 in MGDGs and 16:0/14:0,16:0/18:3,and 18:4/18:3 in SQDGs.In addition,diacylglycerol(DAG)was the most abundant acylglycerols;the content of 22:6/18:4-DAG was the highest.There was a little amount of glycosphingolipid(GSL)in chloroplast.Digalactosylmonoglyceride(DGMG),monogalactosylmonoglyceride(MGMG),sulfoquinovosylmonoacylglycerol(SQMG),monoglyceride(MAG),phospholi-pids(PLs),ceramide(Cer)and betaine lipids were nearly undetectable in chloroplast.The fatty acid proportions of DGDGs,MGDGs,SQDGs,DAGs,triglycerides(TAGs)and GSLs were either higher or lower than or similar to those of whole-cell.Collectively,our isolation approach is applicable to many aspects of chloroplast biology,and may offer a reference for the isolation of chloroplasts from other marine microalgae.
文摘Unicellular micro-alga Chlamydomonas reinhardtii has been recognized as a promising host for expressing recombinant proteins albeit its limited utility due to low levels of heterologous protein expression. Here, transcription of the 3.4-kb mosquito-larvicidal cry4Ba gene from Bacillus thuringiensis in transgenic C. reinhardtii chloroplasts under control of the promoter and 5’-untranslated region of photosynthetic psbA gene was accomplished. Inverted repeats in chloroplast genomes of the host strain with deleted endogenous psbA genes were selected as recombination targets. Two transformant lines were obtained by dual-phenotypic screening via exhibition of resistance to spectinomycin and restoration of photosynthetic activity. Stable and site-specific integration of intact cry4Ba and psbA genes into chloroplast genomes found in both transgenic lines implied homoplasmy of organelle populations. Achievement in cotranscription of cry4Ba and psbA transgenes revealed by RT-PCR and Northern blot analyses demonstrates the sufficiency of this system’s transcription machinery, offering the further innovation for insecticidal protein production.
基金The National Natural Science Foundation of China under contract Nos 31140070,31271397 and 41206116the algal transcrip-tome sequencing was supported by 1KP Project(www.onekp.com)
文摘The chloroplast and mitochondrion of brown algae （Class Phaeophyceae of Phylum Ochrophyta） may have originated from different endosymbiosis. In this study, we carried out phylogenomic analysis to distinguish their evolutionary lineages by using algal RNA-seq datasets of the 1 000 Plants （1KP） Project and publicly available complete genomes of mitochondria and chloroplasts of Kingdom Chromista. We have found that there is a split between Class Phaeophyceae of Phylum Ochrophyta and the others （Phylum Cryptophyta and Haptophyta） in Kingdom Chromista, and identified more diversity in chloroplast genes than mitochondrial ones in their phylogenetic trees. Taxonomy resolution for Class Phaeophyceae showed that it was divided into Laminariales-Ectocarpales clade and Fucales clade, and phylogenetic positions of Kjellmaniella crassi-folia, Hizikia fusifrome and Ishige okamurai were confirmed. Our analysis provided the basic phylogenetic relationships of Chromista algae, and demonstrated their potential ability to study endosymbiotic events.
基金The National Natural Science Foundation of China under contract Nos 31140070,31271397 and 41206116the algal transcrip-tome sequencing was supported by 1KP Project(www.onekp.com)
文摘The chloroplast and mitochondrion of red algae （Phylum Rhodophyta） may have originated from different endosymbiosis. In this study, we carried out phylogenomic analysis to distinguish their evolutionary lin-eages by using red algal RNA-seq datasets of the 1 000 Plants （1KP） Project and publicly available complete genomes of mitochondria and chloroplasts of Rhodophyta. We have found that red algae were divided into three clades of orders, Florideophyceae, Bangiophyceae and Cyanidiophyceae. Taxonomy resolution for Class Florideophyceae showed that Order Gigartinales was close to Order Halymeniales, while Order Graci-lariales was in a clade of Order Ceramials. We confirmed Prionitis divaricata （Family Halymeniaceae） was closely related to the clade of Order Gracilariales, rather than to genus Grateloupia of Order Halymeniales as reported before. Furthermore, we found both mitochondrial and chloroplastic genes in Rhodophyta under negative selection （Ka/Ks〈1）, suggesting that red algae, as one primitive group of eukaryotic algae, might share joint evolutionary history with these two organelles for a long time, although we identified some dif-ferences in their phylogenetic trees. Our analysis provided the basic phylogenetic relationships of red algae, and demonstrated their potential ability to study endosymbiotic events.
文摘Wang G,Hong M,Yang C,et al.Biomimetic chloroplasts:Two-phase microfluidic platforms with selective permeability for artificial photosynthesis.Droplet.2025;4(4):e70019.https://doi.org/10.1002/dro2.70019 The corresponding author information in the published version was incomplete due to an oversight during submission.The correct corresponding authors are.
基金National Natural Science Foundation of China,Grant/Award Number:31901057General Science ProgramofWuxi Healthcare Commission,Grant/Award Number:M202347+5 种基金Fundamental Research Funds for the Central Universities,Grant/Award Numbers:2682016CX101,2682025ZTPY047Foundation for Outstanding Young Scientist in Shandong Province,Grant/Award Number:ZR2024YQ064Shandong Province Science and Technology Small and Medium Enterprises Innovation Capacity Improvement Project,Grant/Award Number:2024TSGC008Shandong Provincial Key Research and Development Project,Grant/Award Numbers:2020CXGC011304,2022CXGC020206TaiShan Scholars,Grant/Award Number:tsqn202408256Qilu University of Technology(Shandong Academy of Sciences),Grant/Award Number:2023JBZ03。
文摘The development of biomimetic chloroplasts offers significant potential in addressing global energy and environmental challenges.Traditional droplet-based models are limited by transmembrane transport inefficiencies,leading to the accumulation of aqueous products that severely hinder reaction performance.In this work,we present a biomimetic chloroplast system that integrates light-dependent and lightindependent reactions,reaction compartments,and selectively permeable interfaces,fabricated using a biphasic microfluidic platform.The permeable interface facilitates continuous substrate–product exchange,mitigating product inhibition and side reactions,thus enhancing reaction efficiency.Furthermore,a quartz spiral tube was engineered to amplify Dean vortex effects,improving mass transfer.This system exhibited a nicotinamide adenine dinucleotide regeneration efficiency during lightdependent reactions that was 5.52 times higher than that of conventional slurry reactors.In the light-independent reaction,the energy conversion efficiency for the transformation ofα-ketoglutaric acid to L-glutamic acid reached 1.45 times that of natural photosynthesis.As the first comprehensive integration of photosynthetic processes within artificial chloroplasts,this work combines biological mechanisms with engineered components to establish a transformative platform for efficient energy conversion and directional biosynthesis.This breakthrough advances the field of photocatalysis and bioinspired technologies,with wide-reaching implications for sustainable energy and synthetic biology applications.
基金supported by grants from the Natural Science Foundation of Fujian Province,China(grant no.2024J09022)the National Natural Science Foundation of China(grant no.32370302)the Open Fund of Fujian Provincial Key Laboratory of Eco-Industrial Green Technology(grant no.WYKF-EIGT2022-6).
文摘In nature,plants are under attack by a range of pathogens.To cope with these pathogens,plants have evolved a sophisticated immune system,including pattern-triggered immunity(PTI)initiated by pattern recognition receptors on the cell surface and effector-triggered immunity(ETI)activated by intracellular nucleotide-binding and leucine-rich repeat receptors.In recent years,increasing evidence has demonstrated that organelles such as the chloroplast play crucial roles in complete activation of plant immunity.In this review,we focus on the chloroplast and summarize its role in regulating the activation of immune events,including influx of calcium(Ca^(2+)),accumulation of reactive oxygen species(ROS),biosynthesis of phytohormones,and expression of defense-related genes.Because information exchange between the chloroplast and the nucleus is very important during plant immunity,we also highlight the importance of chloroplast-nucleus communication via stromules in plant immunity.This review reveals the function of the chloroplast in maintaining the trade-off between plant growth and immunity,and expands our understanding of how chloroplasts enable complete activation of plant immunity.
基金Supported by the National Natural Science Foundation(Grant No.30770178)Beijing Municipal Natural Science Foundation Key Fund Projects(B)(Grant No.KZ200710028013)
文摘Iron is an essential nutrient for plant metabolism such that Fe-limited plants display chlorosis and suffer from reduced photosynthetic efficiency.Differential display previously identified genes whose expression was elevated in Fe-deficient maize roots.Here,we describe the functional characterization of one of the genes identified in the screen,ZmFDR3(Zea maize Fe-deficiency-related).Heterologous functional complementation assays using a yeast iron uptake mutant showed that ZmFDR3 functions in iron transport.ZmFDR3 contains a domain found in FliN-proteins of the type III secretion system and is predicted to localize to the thylakoid of plastids.Fluorescence immunocytochemistry showed that ZmFDR3 is localized in the plastids of roots,stems and leaves,with high expression found in guard cell chloroplasts.Transgenic tobacco expressing a 35S-ZmFDR3 construct contains elevated iron content,displays well arranged thylakoid membranes and has photosynthetic indices that are higher than those of the wild type.Together,these results suggest that ZmFDR3 functions in chloroplast iron transport.
文摘Recent technical advances in electrophysiological measurements, organelle-targeted fluorescence imaging, and organelle proteomics have pushed the research of ion transport a step forward in the case of the plant bioenergetic organelles, chloroplasts and mitochondria, leading to the molecular identification and functional characterization of several ion transport systems in recent years. Here we focus on channels that mediate relatively high-rate ion and water flux and summarize the current knowledge in this field, focusing on targeting mechanisms, proteomics, electrophysiology, and physiological function. In addition, since chloroplasts evolved from a cyanobacterial ancestor, we give an overview of the information available about cyanobacterial ion channels and discuss the evolutionary origin of chloroplast channels. The recent molecular identification of some of these ion channels allowed their physiological functions to be studied using genetically modified Arabidopsis plants and cyanobacteria. The view is emerging that alteration of chloroplast and mitochondrial ion homeostasis leads to organelle dysfunction, which in turn significantly affects the energy metabolism of the whole organism. Clear-cut identification of genes encoding for chan- nels in these organelles, however, remains a major challenge in this rapidly developing field. Multiple stra- tegies including bioinformatics, cell biology, electrophysiology, use of organelle-targeted ion-sensitive probes, genetics, and identification of signals eliciting specific ion fluxes across organelle membranes should provide a better understanding of the physiological role of organellar channels and their contribution to signaling pathways in plants in the future.
文摘Protein translocation across membranes is a fundamental cellular process. The majority of the proteins of organelles such as mitochondria and chloroplasts is synthesized in the cytosol and subsequently imported in a posttranslational manner. The precursor proteins have to be unfolded at least for translocation, but it has also been assumed that they are unfolded during transport to the organelle in the cytosol. Unfolding is governed by chaperones and the translocon itself. At the same time, chaperones provide the energy for the import process. The energetic properties of the chloroplast translocon were studied by import of the Ig-like module of the muscle protein titin fused to the transit peptide of the chloroplast targeted oxygen evolving complex subunit of 33 kDa （OE33）. Our results suggest that p（OE33）titin is folded prior to import and that translocation is initiated by unfolding after having bound to the translocon at the chloroplast surface. Using a set of stabilizing and destabilizing mutants of titin previously analyzed by atomic force microscopy and as passenger for mitochondrial translocation, we studied the unfolding force provided by the chloroplast translocon. Based on these results, a model for translocation is discussed.
文摘Plants possess both types of endosymbiotic organelles, chloroplasts and mitochondria. Transit peptides and presequences function as signal sequences for specific import into chloroplasts and mitochondria, respectively. However, how these highly similar signal sequences confer the protein import specificity remains elusive. Here, we show that mitochondrial- or chloroplast-specific import involves two distinct steps, specificity determination and translocation across envelopes, which are mediated by the N-terminal regions and functionally interchangeable C-terminal regions, respectively, of transit peptides and presequences. A domain harboring multiple-arginine and hydrophobic sequence motifs in the N-terminal regions of presequences was identified as the mitochondrial specificity factor. The presence of this domain and the absence of arginine residues in the N-terminal regions of otherwise common targeting signals confers specificity of protein import into mitochondria and chloroplasts, respectively. AtToc159, a chloroplast import receptor, also contributes to determining chloroplast import specificity. We propose that common ancestral sequences were functionalized into mitochondrial- and chloroplast-specific signal sequences by the presence and absence, respectively, of multiple-arginine and hydrophobic sequence motifs in the N-terminal region.
基金The Foundation of Shanghai Science and Technology Committee(Grant No.17391900600)The Program for Professor of Special Appointment(Eastern Scholar)from The Shanghai Bureau of Higher Education(2011 and 2017)+1 种基金The Natural and Science Foundation of Heilongjiang Provence(Grant No.ZD2019C003)to Shaojun DaiThe Fund of Shanghai Engineering Research Center of Plant Germplasm Resources(Grant No.17DZ2252700)。
文摘Alkali-salinity exerts severe osmotic,ionic,and high-p H stresses to plants.To understand the alkali-salinity responsive mechanisms underlying photosynthetic modulation and reactive oxygen species(ROS)homeostasis,physiological and diverse quantitative proteomics analyses of alkaligrass(Puccinellia tenuiflora)under Na_(2)CO_(3)stress were conducted.In addition,Western blot,real-time PCR,and transgenic techniques were applied to validate the proteomic results and test the functions of the Na_(2)CO_(3)-responsive proteins.A total of 104 and 102 Na_(2)CO_(3)-responsive proteins were identified in leaves and chloroplasts,respectively.In addition,84 Na_(2)CO_(3)-responsive phosphoproteins were identified,including 56 new phosphorylation sites in 56 phosphoproteins from chloroplasts,which are crucial for the regulation of photosynthesis,ion transport,signal transduction,and energy homeostasis.A full-length Pt FBA encoding an alkaligrass chloroplastic fructosebisphosphate aldolase(FBA)was overexpressed in wild-type cells of cyanobacterium Synechocystis sp.Strain PCC 6803,leading to enhanced Na_(2)CO_(3)tolerance.All these results indicate that thermal dissipation,state transition,cyclic electron transport,photorespiration,repair of photosystem(PS)Ⅱ,PSI activity,and ROS homeostasis were altered in response to Na_(2)CO_(3)stress,which help to improve our understanding of the Na_(2)CO_(3)-responsive mechanisms in halophytes.
文摘Chloroplasts and mitochondria are both thought to have arisen through primary endosymbiosis (Kutschera and Niklas, 2005). As each organelle evolved, most of its genome was transferred to the host nucleus resulting in the vast majority of its proteome being nuclear encoded and synthesized on cytosolic ribosomes (Shi and Theg, 2013).
基金Supported by the National Natural Science Foundation of China(No.31970217)the Scientific and Technological Innovation Programs of Higher Education Institution in Shanxi(No.2019L0070)。
文摘Stephanodiscaceae is one of the most diverse family of the freshwater centric diatoms.However,the scarcity of whole plastome data poses a significant challenge to the undertaking of genomic studies on this taxonomic group.We collected data on the plastid genomes from 33 members of the Stephanodiscaceae and its close relatives,including 12 newly-sequenced genomes and 21 deposited in National Center for Biotechnology Information(NCBI).Phylogenetic trees are yielded five major clades based on homologous genes.The features of the plastid genomes,including repeat sequences,codon usage,and selection pressure for each clade,are analyzed.The paper makes a contribution to the field of diatom genomics by describing the structural characteristics of the plastid genomes in the Stephanodiscaceae and its closely related species,complemented by related analyses.It provides crucial data that will serve as indispensable references for future research.
基金the National Key Research and Development Program of China(2017YFD0102001,2018YFD0100806,2017YFD0101201)the National Transgenic Major Program of China(2018ZX0801006B,2018ZX0800922B)+3 种基金the National Natural Science Foundation of China(31971958,31771875,31871702)the Fundamental Research Funds for the Central Universities of China(06500136)the"Ten Thousand Plan"-National High Level Talents Special Support Plan(to X.W.)the Beijing Science&Technology Plan Program(Z191100004019005).
文摘Genic male sterility(GMS)is critical for heterosis utilization and hybrid seed production.Although GMS mutants and genes have been studied extensively in plants,it has remained unclear whether chloroplast-associated photosynthetic and metabolic activities are involved in the regulation of anther development.In this study,we characterized the function of ZmMs33/ZmGPAT6,which encodes a member of the glycerol-3-phosphate acyltransferase(GPAT)family that catalyzes the first step of the glycerolipid synthetic pathway.We found that normal structure and function of endothecium(En)chloroplasts maintained by ZmMs33-mediated lipid biosynthesis in tapetal cells are crucial for maize anther development.ZmMs33 is expressed mainly in the tapetum at early anther developmental stages and critical for cell proliferation and expansion at late stages.Chloroplasts in En cells of wild-type anthers function as starch storage sites before stage 10 but as photosynthetic factories since stage 10 to enable starch metabolism and carbohydrate supply.Loss of ZmMs33 function inhibits the biosynthesis of glycolipids and phospholipids,which are major components of En chloroplast membranes,and disrupts the development and function of En chloroplasts,resulting in the formation of abnormal En chloroplasts containing numerous starch granules.Further analyses reveal that starch synthesis during the day and starch degradation at night are greatly suppressed in the mutant anthers,leading to carbon starvation and low energy status,as evidenced by low trehalose-6-phosphate content and a reduced ATP/AMP ratio.The energy sensor and inducer of autophagy,SnRK1,was activated to induce early and excessive autophagy,premature PCD,and metabolic reprogramming in tapetal cells,finally arresting the elongation and development of mutant anthers.Taken together,our results not only show that ZmMs33 is required for normal structure and function of En chloroplasts but also reveal that starch metabolism and photosynthetic activities of En chloroplasts at different developmental stages are essential for normal anther development.These findings provide novel insights for understanding how lipid biosynthesis in the tapetum,the structure and function of En chloroplasts,and energy and substance metabolism are coordinated to maintain maize anther development.
