Large Subunit Of Ribulose Bisphosphate Carboxylase Research Articles

Purification, crystallization, and X-ray crystallographic analysis of ribulose bisphosphate carboxylase large subunit from Hydrogenovibrio marinus

Purification, crystallization, and X-ray crystallographic analysis of ribulose bisphosphate carboxylase large subunit from <i>Hydrogenovibrio marinus</i>

Enhanced genome-wide association reveals the role of YABBY11-NGATHA-LIKE1 in leaf serration development of Populus.

Leaf margins are complex plant morphological features that contribute to leaf shape diversity, which affects plant structure, yield, and adaptation. Although several leaf margin regulators have been identified to date, the genetic basis of their natural variation has not been fully elucidated. In this study, we profiled two distinct leaf morphology types (serrated and smooth) using the persistent homology mathematical framework (PHMF) in two poplar species (Populus tomentosa and Populus simonii, respectively). A combined genome-wide association study (GWAS) and expression quantitative trait nucleotide (eQTN) mapping were applied to create a leaf morphology control module using data from P. tomentosa and P. simonii populations. Natural variation in leaf margins was associated with YABBY11 (YAB11) transcript abundance in poplar. In P. tomentosa, PtoYAB11 carries a premature stop codon (PtoYAB11PSC), resulting in the loss of its positive regulation of NGATHA-LIKE1 (PtoNGAL-1) and RIBULOSE BISPHOSPHATE CARBOXYLASE LARGE SUBUNIT (PtoRBCL). Overexpression of PtoYAB11PSC promoted serrated leaf margins, enlarged leaves, enhanced photosynthesis, and increased biomass. Overexpression of PsiYAB11 in P. tomentosa promoted smooth leaf margins, higher stomatal density, and greater light damage repair ability. In poplar, YAB11-NGAL1 is sensitive to environmental conditions, acts as a positive regulator of leaf margin serration, and may also link environmental signaling to leaf morphological plasticity.

Proteomics and photosynthetic apparatus response to vermicompost attenuation of salinity stress Vicia faba leaves

Crop production and growth are severely affected by salt stress. Nevertheless, the bio-fertilizer vermicompost (VC) can be participated as a potent inhibitor of salinity on plant growth and crop production by regulating photosynthetic efficiency. We investigated the effect of VC on photosynthetic performance of salt-stressed broad bean (Vicia faba L. Aspani cultivar). Seeds were grown in soil mixture; clay and sand in ratio 1:2 by volume with five different volumetric ratios of VC; 0, 2.5, 5, 10 and 15% irrigated with either water and/or 200 mM NaCl. Leaf area, Na and K contents, chlorophylls, photosystem II efficiency, Rubisco content, soluble sugars, chloroplasts’ organization and proteomics were analyzed. The imposed stress decrease leaf area, chlorophyll contents, maximum quantum efficiency (Fv/Fm), Rubisco content, increase soluble sugars and damage chloroplasts organization. Salinity upregulated glucose-1-phosphate adenylyl transferase, ribulose bisphosphate carboxylase large subunit and chloroplastic peptidyl-prolyl cis–trans isomerase. The increased leaf area, chlorophyll a, b and carotenoids, maximum quantum efficiency of photosystem II, Rubisco content, improving the degeneration of thylakoid lamellae and lessening plastoglobuli number in thylakoid membranes are the major benefits attained with vermicompost treatments under salt stress.Analysis of proteomic revealed that VC upregulated chloroplastic ferredoxin–NADP reductase, plastocyanin, polyphenol oxidase, peptidyl-prolyl cis–trans isomerase, alpha-glucan phosphorylase H isozyme and maturase expression under salt stress. The results suggest that VC controls protein expression at the level of transcriptional and translational which may conserve photosynthetic components and prevent salt-induced harmful effects in broad bean plants.

Morpho-anatomical characterization and DNA barcoding of Achillea millefolium L.

Abstract. Ilham M,Mukarromah SR, Rakashiwi GA, Indriati DT, Yoku BF, Purnama PR, Junairiah, Prasongsuk S,Purnobasuki H, Wahyuni DK. 2022. Morpho-anatomical characterizationand DNA barcoding of Achillea millefolium L. Biodiversitas 23: 1958-1969. One of the important things to study the distribution of secondary metabolites in the plant body is to carry out the identification process. Morphological markers have several limitations to recognize plants, therefore supporting data is needed so that the information becomes more comprehensive. This study aims to identify Achillea millefolium L. based on morphological, anatomical, and DNA barcoding markers to obtain specific data and avoid confusion. Morphological studies were carried out descriptively using vegetative organs, while anatomical studies of rhizomes, stems, and leaves used the paraffin method. The DNA barcoding was performed by analyzinggenes from 3 different individuals. The research was carried out by amplifying and sequencing the partial gene in the ribulose-bisphosphate carboxylaselarge subunit (rbcL) regions and maturase-K (matK). The results showed that the plant had taproots, short stems due to root rosette and the leaves were double compound. The rhizome and stem tissues had almost the same structure, while the leaves had a tissue arrangement that was similar to other plants in general, except that the mesophyll tissue was undifferentiated. The results of DNA barcoding showed a percentage of identity above 98% for both the rbcLand matK genes.

Enhancement of Biomass Production in Colony-Forming Green Algae, Botryosphaerella sudetica, Under Mixotrophic Cultivation.

In this study, we characterized the potential of colony-forming green algae, Botryosphaerella sudetica KNUA107, isolated from Ulleung Island, South Korea, as a bioresource and analyzed the effects of mixotrophic cultivation on its bioresource production efficiency. Internal transcribed spacer (ITS) (ITS1, 5.8S, and ITS2), ribulose bisphosphate carboxylase large subunit (rbcL), and elongation factor Tu (tufa) regions were used for molecular identification and phylogenetic analysis. B. sudetica KNUA107 had a strong relationship with the green algae of Botryococcus and Botryosphaerella genera, which are colony-forming species, and was also associated with members of the Neochloris genus. To improve biomass productivity, we tested mixotrophic cultivation conditions using several organic carbon sources. Glucose supplementation stimulated B. sudetica KNUA107 growth and reduced the time needed to reach the stationary phase. In addition, the colony size was 1.5–2.0 times larger with glucose than in photoautotrophic cultures, and settleability improved in proportion to colony size. The total lipid content and biomass productivity were also higher in cultures supplemented with glucose. Among the lipid components, saturated fatty acids and monounsaturated fatty acids had the highest proportion. Our study suggests that B. sudetica KNUA107, which has enhanced efficiency in biomass production and lipid components under mixotrophic cultivation, has high potential as a bioresource.

Molecular Identification and Evaluation of the Genetic Diversity of Dendrobium Species Collected in Southern Vietnam

Dendrobium has been widely used not only as ornamental plants but also as food and medicines. The identification and evaluation of the genetic diversity of Dendrobium species support the conservation of genetic resources of endemic Dendrobium species. Uniquely identifying Dendrobium species used as medicines helps avoid misuse of medicinal herbs. However, it is challenging to identify Dendrobium species morphologically during their immature stage. Based on the DNA barcoding method, it is now possible to efficiently identify species in a shorter time. In this study, the genetic diversity of 76 Dendrobium samples from Southern Vietnam was investigated based on the ITS (Internal transcribed spacer), ITS2, matK (Maturase_K), rbcL (ribulose-bisphosphate carboxylase large subunit) and trnH-psbA (the internal space of the gene coding histidine transfer RNA (trnH) and gene coding protein D1, a polypeptide of the photosystem I reaction center (psaB)) regions. The ITS region was found to have the best identification potential. Nineteen out of 24 Dendrobium species were identified based on phylogenetic tree and Indel information of this region. Among these, seven identified species were used as medicinal herbs. The results of this research contributed to the conservation, propagation, and hybridization of indigenous Dendrobium species in Southern Vietnam.

Molecular characterization and in vitro interaction analysis of Op14-3-3 μ protein from Opuntia ficus-indica: identification of a new client protein from shikimate pathway

In plants, 14-3-3 proteins are important modulators of protein-protein interactions in response to environmental stresses. The aim of the present work was to characterize one Opuntia ficus-indica 14-3-3 and get information about its client proteins. To achieve this goal, O. ficus-indica 14-3-3 cDNA, named as Op14-3-3 μ, was amplified by 3’-RACE methodology. Op14-3-3 μ contains an Open Reading Frame of 786 bp encoding a 261 amino acids protein. Op14-3-3 μ cDNA was cloned into a bacterial expression system and recombinant protein was purified. Differential Scanning Fluorimetry, Dynamic Light Scattering, and Ion Mobility-Mass Spectrometry were used for Op14-3-3 μ protein characterization, and Affinity-Purification-Mass Spectrometry analysis approach was used to obtain information about their potential client proteins. Pyrophosphate-fructose 6-phosphate 1-phosphotransferase, ribulose bisphosphate carboxylase large subunit, and vacuolar-type H+-ATPase were identified. Interestingly chorismate mutase p-prephenate dehydratase was also identified. Op14-3-3 μ down-regulation was observed in Opuntia calluses when they were induced with Jasmonic Acid, while increased accumulation of Op14-3-3 μ protein was observed. The putative interaction of 14-3-3 μ with chorismate mutase, which have not been reported before, suggest that Op14-3-3 μ could be an important regulator of metabolites biosynthesis and responses to stress in Opuntia spp. SignificanceOpuntia species are important crops in arid and semiarid areas worldwide, but despite its relevance, little information about their tolerance mechanism to cope with harsh environmental conditions is reported. 14-3-3 proteins have gained attention due to its participation as protein-protein regulators and have been linked with primary metabolism and hormones responses. Here we present the characterization of the first Opuntia ficus-indica 14-3-3 (Op14-3-3) protein using affinity purification-mass spectrometry (AP-MS) strategy. Op14-3-3 has high homology with other 14-3-3 from Caryophyllales. A novel Op14-3-3 client protein has been identified; the chorismate mutase p-prephenate dehydratase, key enzyme that links the primary with secondary metabolism. The present results open new questions about the Opuntia spp. pathways mechanisms in response to environmental stress and the importance of 14-3-3 proteins in betalains biosynthesis.

Molecular identification of Allium ochotense and Allium microdictyon using multiplex-PCR based on single nucleotide polymorphisms

Allium ochotense and Allium microdictyon are commonly known as ‘Mountain garlic’ and are popular, economically important species in many countries such as Korea, China, and Mongolia. Their leaves are used as culinary side dishes and in traditional medicines. In Korea, these two species are at risk of extinction due to damage to their natural habitat and thus, conservation and breeding programs are needed. However, their identification relies mostly on morphological data, which is limited and until recently, led to classifying these two species under A. victorialis. In the present study, a simple and reliable method of molecular identification was developed to distinguish A. ochotense from A. microdictyon that targets four barcoding regions: the internal transcribed spacer (ITS), the maturase K gene (matK), the chloroplast psbA-trnH intergenic region, and the ribulose-bisphosphate carboxylase large subunit gene (rbcL). Single nucleotide polymorphisms (SNPs) were found in ITS and matK regions, and species-specific primers were designed based solely on the SNP at position 680 of the ITS region that could differentiate A. ochotense from A. microdictyon. Using these primers in amplification refractory mutation system (ARMS)-PCR, A. ochotense, and A. microdictyon could be simultaneously and efficiently distinguished. This study is the first to report a simple, rapid, and efficient method for discriminating A. ochotense and A. microdictyon, indicating the utility of species-specific markers in the development of conservation and breeding programs.

DNA Barcoding Green Microalgae Isolated from Neotropical Inland Waters.

This study evaluated the feasibility of using the Ribulose Bisphosphate Carboxylase Large subunit gene (rbcL) and the Internal Transcribed Spacers 1 and 2 of the nuclear rDNA (nuITS1 and nuITS2) markers for identifying a very diverse, albeit poorly known group, of green microalgae from neotropical inland waters. Fifty-one freshwater green microalgae strains isolated from Brazil, the largest biodiversity reservoir in the neotropics, were submitted to DNA barcoding. Currently available universal primers for ITS1-5.8S-ITS2 region amplification were sufficient to successfully amplify and sequence 47 (92%) of the samples. On the other hand, new sets of primers had to be designed for rbcL, which allowed 96% of the samples to be sequenced. Thirty-five percent of the strains could be unambiguously identified to the species level based either on nuITS1 or nuITS2 sequences’ using barcode gap calculations. nuITS2 Compensatory Base Change (CBC) and ITS1-5.8S-ITS2 region phylogenetic analysis, together with morphological inspection, confirmed the identification accuracy. In contrast, only 6% of the strains could be assigned to the correct species based solely on rbcL sequences. In conclusion, the data presented here indicates that either nuITS1 or nuITS2 are useful markers for DNA barcoding of freshwater green microalgae, with advantage for nuITS2 due to the larger availability of analytical tools and reference barcodes deposited at databases for this marker.

Forensic DNA Analysis of Wheat Flour as Commonly Used in White Powder Cases.

In the wake of terrorist attacks using anthrax and ricin, white powder is often encountered in cases of malicious mischief and terrorist threats. Wheat flour is a common white powder encountered in such criminal investigations. We used DNA analysis to investigate wheat flour samples for identification and discrimination as trace evidence. Species identification of commercially available wheat flour was carried out by sequencing a partial region of the ribulose bisphosphate carboxylase large subunit gene (rbcL). Samples were discriminated using short tandem repeat (STR) analysis. The rbcL sequences of all wheat flour samples were identical and showed a high level of similarity to known wheat (Triticum aestivum L.) sequences. Furthermore, flours had characteristic patterns in STR analyses, with specific cultivars showing distinctive patterns. These results suggested that the identification of wheat flour species is possible using rbcL sequencing, and that STR analysis is useful for discriminating between samples.

Characterization of Talinum triangulare (Jacq.) Willd. germplasm using molecular descriptors

Talinum triangulare is a medicinal herb known to have originated from tropical Africa and is now widely cultivated in the humid tropical countries. The characterization of plant germplasm using molecular descriptors aids in describing the genotypic traits of the plant T. triangulare. Ten different accessions of T. triangulare were collected from nine districts of Tamil Nadu. High quality genomic DNA was isolated from the different samples, checked for purity and quantified. The DNA samples were subjected to PCR amplification using RAPD markers and by DNA barcoding technique. RAPD fingerprints were generated for the 10 different accessions of T. triangulare for the first time. Ten random decamer primers resulted in 73.08% of polymorphism by producing a total of 78 fragments, of which, 57 bands were determined as polymorphic loci. Phylogenetic relationship and intra-specific variation among the samples were established by constructing a dendrogram based on Jaccard's coefficient. DNA barcoding studies included the amplification of chloroplast large subunit of ribulose-bisphosphate carboxylase (rbcL), trnH-psbA intergenic spacer (trnH-psbA), maturase K (matK) and nuclear internal transcribed spacer (ITS). The amplicons were gel eluted, sequenced and checked for homology by using the BLAST tool. However, no variation was detected among the samples after sequencing, proving that the accessions were identical at the genetic level.

미크로네시아 웨노섬 서식 망그로브 식물의 분류 및 항산화 활성

Mangrove plants serve as a sink of heavy metals and contain phenolic compounds at a high level. Therefore, with mangrove plants, recent studies to develop phytoremediation and natural antioxidants have been conducted in the commercial and academic fields. In the present study, six mangroves in Weno Island of Micronesia were investigated for their phylogenetic relationship and antioxidant activities. First, to determine the phylogenetic relationship among them, rbcL (large subunit of ribulose-bisphosphate carboxylase), one of the chloroplast genes, was used as a molecular marker. According to the data, Xylocarpus, Sonneratia and Rhizophora showed close similarity but not Excoecaria. The levels of phenolic compounds in the bark were abundant in R. apiculata and X. granatum, accounting for 1.10 mM/mg, while R. stylosa and S. alba contained the low amounts, representing 0.73 mM/mg and 0.72 mM/mg, respectively (p<0.05). In addition, bark extracts from R. apiculata, X. granatum, X. moluccensis, and E. agallocha had high antioxidant activities through the DPPH radical scavenging activity and ABTS analysis, whereas S. alba showed the lowest activities. These results suggest that the bark of R. apiculata can be used as a good source for the development of natural antioxidants.

DNA identification of Salvia divinorum samples

Salvia divinorum (diviner's sage) is a plant in the mint family that produces an hallucinogenic compound, salvinorin A. The plant is used, often by chewing or smoking, as a "recreational" drug source and is regulated or banned in several states and countries. We describe a simple DNA technique, polymerase chain reaction of the ribulose bisphosphate carboxylase large subunit (rbcL) gene, that can distinguish S. divinorum leaf pieces from pieces of tobacco or cannabis. We have also found DNA sequences adjacent to the chloroplast leucine transfer RNA (trnL) gene that are specific to S. divinorum and distinguish it from other horticulturally popular Salvia species. We report some significant differences between the S. divinorum trnL sequences we determined and those now published in GenBank.

Characterization of Cupric Glutamate Extinguishing Mechanism of Alexandrium sp. LC3 with Two-dimensional Electrophoresis and MALDI-TOF MS

Mechanisms by which cupric glutamate, a novel algicide, extinguishes Alexandrium sp. LC3 are shown in this study. We show that cupric glutamate not only stimulated the production of malonaldehyde (MDA) and dramatically promoted cell plasma membrane permeability (p < 0.01) but also remarkably reduced sulfhydryl (SH) group content (p < 0.01). Analysis of protein expression profiles by two-dimensional electrophoresis (2-DE) indicated that only 47 protein spots were detected in both control and cupric glutamate treated cells. Three reliable spots were identified by matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS) as ribulose-bisphosphate carboxylase large subunit precursor, RNA polymerase beta chain, and hypothetical protein, which can be well correlated with cupric glutamate stress. Based on above results, we hypothesize that the extinguishing mechanisms include (1) the cell membrane being damaged by cupric glutamate; (2) cupric glutamate probably induced denaturation and disintegration of intracellular protein, which led to inhibition of cell growth.

Otzi's last meals: DNA analysis of the intestinal content of the Neolithic glacier mummy from the Alps.

Samples of the intestinal content were collected from the ileum and colon of the Neolithic glacier mummy popularly known as the Tyrolean Iceman, or Otzi. DNA was extracted from the samples and PCR amplified, using a variety of primer pairs designed to bind to different genes (mammal mitochondrial 12S ribosomal RNA gene, plant/fungal nuclear 18S ribosomal RNA gene, plant chloroplast ribulose bisphosphate carboxylase large subunit gene). This made it possible to distinguish between animal and plant food residues (macroremains) and pollen (microremains). According to the DNA reconstruction, the man's last meal was composed of red deer (Cervus elaphus) meat, and, possibly, cereals; this meal had been preceded by another one based on ibex (Capra ibex), different species of dicots, and cereals. The DNA spectrum corresponding to pollen residues in the colon, on the other hand, fits with the hypothesis that the last journey of the Neolithic hunter/warrior was made through a subalpine coniferous forest to the site at over 3,200 m above sea level, where his mummified body was to be discovered 5,000 years later.

Effects of mutations at residue 309 of the large subunit of ribulosebisphosphate carboxylase from Synechococcus PCC 6301

Previous studies [G. S. Hudson et al. (1989) J. Biol. Chem. 265, 808–814] showed that the faster turnover rates and lower affinities for CO 2 of ribulosebisphosphate carboxylase/oxygenases from C 4 plants, compared to C 3 and C 3 C 4 plants, were specified by the chloroplast-encoded large subunits. In pairs of closely related C 3 and C 4 species from three genera, these kinetic changes were accompanied by only three to six amino acid residue substitutions, depending on the genus. None of these substitutions occurred near the active site and only one, 309Met (C 3) to Ile (C 4), was common to all three genera. Unlike the plant carboxylases, the highly homologous enzyme from the cyanobacterium Synechococcus PCC 6301 folds and assembles properly when its rbcL and rbcS genes are coexpressed in Escherichia coli. Furthermore, the cyanobacterial enzyme has Ile at position 309 of the large subunit, a high turnover number, and a poor affinity for CO 2. 309Ile was replaced with Met and several other residues by site-directed mutagenesis of the cyanobacterial rbcL. Met and Leu were tolerated at this position with no alteration in the kinetic or structural properties of the assembled holoenzyme. However, substitution with Val, Gly, Trp, or Arg prevented the assembly of the subunits. The indifference to Met or Ile at this position, as well as the tolerance for Leu which is not observed with any natural ribulosebisphosphate carboxylase, leads to the conclusion that either the 309Met/Ile substitution has no effect on the kinetic properties of the plant enzyme, despite the correlation apparent in previous studies, or the cyanobacterial enzyme is sufficiently different from the plant enzyme in other respects that the influence of residue 309 is masked.

Comparisons of rbcL genes for the large subunit of ribulose-bisphosphate carboxylase from closely related C3 and C4 plant species.

Ribulosebisphosphate carboxylase/oxygenase from C4 plants exhibits higher turnover rates and lower affinities for CO2 than the enzyme from C3 plants or C3-C4 intermediate species. This property is shown to be inherited maternally in reciprocal interspecific crosses between two Flaveria species, and thus must be specified by the chloroplast-encoded large subunits. To investigate the amino acid changes responsible, the chloroplast rbcL genes from three pairs of C3 and C4 species from three genera (Flaveria, Atriplex, and Neurachne) were cloned and sequenced. Comparisons of the predicted amino acid sequences from species of the same genus revealed a limited number of changes within each pair, ranging from three to six, of which only one (309Met (C3) to Ile (C4] was consistently observed. This residue occurs in the loop connecting the carboxyl end of beta strand 5 with the amino end of alpha helix 5 in the alpha/beta barrel of the large subunit, and is close to the active site in a region which makes interdomain and intersubunit contacts. However, it is unlikely that a change of this residue alone is responsible for the alteration of kinetic properties. Nucleotide sequence comparisons of the rbcL genes showed no significant or consistent changes in the promoter and transcribed but nontranslated regions to suggest why rbcL is not expressed in C4 leaf mesophyll cells. It is concluded that mutations in rbcL have led to an alteration of the kinetics but not the expression of ribulose-bisphosphate carboxylase.

Relationship between Gene Dosage and Gene Expression in the Chloroplast of Chlamydomonas reinhardtii

Expression of three chloroplast genes encoding proteins of different chloroplast complexes and the rRNA gene has been examined in cells having reduced numbers of chloroplast genomes as a result of growth in the presence of the thymidine analog 5-fluorodeoxyuridine. While accumulation of total mRNA for rpl2 (ribosomal protein L-1), rbcL (ribulose bisphosphate carboxylase large subunit) and atpA (alpha-subunit of ATP synthase) declined with gene copy number, the levels of translatable mRNA and rates of synthesis of these three proteins were largely unaffected. Accumulation of rRNA declined less precipitously than mRNA levels for the three proteins in response to the reduction in chloroplast genome number. Chlamydomonas appears to compensate for reductions in the number of chloroplast genomes at several different levels. Populations of cells with only one-fourth the wild-type amount of chloroplast DNA per cell on average have half the normal level of chloroplast ribosomes and nearly normal rates of CO(2) fixation and levels of specific chloroplast encoded proteins. These results suggest that normal cells accumulate a large excess of transcripts for chloroplast genes and that levels of expression of these genes are regulated by posttranscriptional mechanisms.

The role of the N-terminus of the large subunit of ribulose-bisphosphate carboxylase investigated by construction and expression of chimaeric genes.

The genes for the large and small subunits of ribulose bisphosphate carboxylase/oxygenase (Rubisco) from Anacystis nidulans have been expressed in Escherichia coli under the control of the lac promoter to produce active enzyme. The enzyme can be purified from the cells to yield up to 200 mg Rubisco/l cultured bacteria, and is indistinguishable from the enzyme extracted from A. nidulans. In order to investigate the role of the N-terminus of the large subunit in catalysis, chimaeric genes were constructed where the DNA coding for the 12 N-terminal amino acids in A. nidulans was replaced by DNA encoding the equivalent, but poorly conserved, region of either the wheat or maize large subunit. These genes, in constructs also containing the gene for the A. nidulans small subunit, were expressed in E. coli and produced enzymes with similar catalytic properties to the wild-type Rubisco of A. nidulans. In contrast, when the N-terminal region of the large subunit was replaced by unrelated amino acids encoded by the pUC8 polylinker, enzyme activity of the expressed protein was reduced by 90% under standard assay conditions, due to an approximately tenfold rise in the Km for ribulose 1,5-bisphosphate. This confirms that the N-terminus of the large subunit has a function in catalysis, either directly in substrate binding or in maintaining the integrity of the active site.

Control of gene expression during higher plant chloroplast biogenesis. Protein synthesis and transcript levels of psbA, psaA-psaB, and rbcL in dark-grown and illuminated barley seedlings.

Etioplasts of 4.5-day-old dark-grown barley synthesize and accumulate most of the membrane and nearly all the soluble polypeptides of mature chloroplasts of light-grown seedlings. Etioplasts do not synthesize a limited set of chloroplast-encoded polypeptides which are major constituents of chloroplast thylakoid membranes: two chlorophyll apoproteins of photosystem I (68 and 65 kDa), two chlorophyll apoproteins of photosystem II (47 and 43 kDa), and a 32-kDa polypeptide which has now been identified as the psbA gene product. Throughout development in the dark, etioplasts were unable to synthesize the chlorophyll apoproteins of photosystem I and II or the psbA gene product despite the presence of significant transcript levels for psbA and psaA-psaB (encode for photosystem I chlorophyll apoproteins). Light was not required for the synthesis of ribulose bisphosphate carboxylase large subunit with the highest rate of large subunit synthesis occurring in young dark-grown seedlings. Illumination of 4.5-day-old dark-grown barley rapidly induced the synthesis of the chlorophyll apoproteins and the psbA gene product at a time when transcript levels for psbA and psaA-psaB did not increase appreciably. Therefore, during the early stages of light-induced development the synthesis of the chlorophyll apoproteins of photosystem I and psbA gene product is regulated at the translational level. With continued chloroplast development in the light, the synthesis of the chlorophyll apoproteins of photosystem I and II decline rapidly as does the synthesis of the large subunit of ribulose bisphosphate carboxylase. The decline in polypeptide synthesis correlated with a decline in rbcL and psaA-psaB transcript levels and a light-dependent decline in plastid rRNA content. In contrast, synthesis of the psbA gene product was maintained throughout light-induced chloroplast development which correlated with the maintenance of psbA transcript levels. However, light is not strictly required for psbA transcript accumulation since psbA transcript levels increased slightly with continued plastid development in dark-grown seedlings.