The unicellular green alga Chlamydomonas reinhardtii displays metabolic flexibility in response to a changing environment. We analyzed expression patterns of its three genomes cells grown under light–dark cycles. Nearly 85% transcribed genes show differential expression, with different sets transcripts being up-regulated over the course day coordinate cellular growth before undergoing cell division. Parallel measurements select metabolites and pigments, physiological parameters, subset...

Plants are the main source of folate in human diets, but many fruits, tubers, and seeds poor this vitamin, deficiency is a worldwide problem. synthesize from pteridine, p -aminobenzoate (PABA), glutamate moieties. Pteridine synthesis capacity known to drop ripening tomato fruit; therefore, we countered decline by fruit-specific overexpression GTP cyclohydrolase I, first enzyme pteridine synthesis. We used synthetic gene based on mammalian because predicted escape feedback control planta ....

Mitochondrial-plastid interdependence within the plant cell is presumed to be essential, but measurable demonstration of this intimate interaction difficult. At level cellular metabolism, several biosynthetic pathways involve both mitochondrial- and plastid-localized steps. However, at an environmental response level, it not clear how two organelles intersect in programmed responses. Here, we provide evidence, using genetic perturbation MutS Homolog1 (MSH1) nuclear gene five species, that...

The established pathways from serine to ethanolamine are indirect and involve decarboxylation of phosphatidylserine. Here we show that plants can decarboxylate directly. Using a radioassay based on (Etn) formation, pyridoxal 5′-phosphate-dependent l-serine decarboxylase (SDC) activity was readily detected in soluble extracts leaves diverse species, including spinach,<i>Arabidopsis,</i> rapeseed. A putative<i>Arabidopsis</i> SDC cDNA identified by searching GenBank^TM for sequences...

It is not known how plants synthesize the p -aminobenzoate (PABA) moiety of folates. In Escherichia coli , PABA made from chorismate in two steps. First, PabA and PabB proteins interact to catalyze transfer amide nitrogen glutamine chorismate, forming 4-amino-4-deoxychorismate (ADC). The PabC protein then mediates elimination pyruvate aromatization give PABA. Fungi, actinomycetes, Plasmodium spp. also but have comprising fused domains homologous PabB. These bipartite are commonly called...

It is not known how plants make the benzenoid ring of ubiquinone, a vital respiratory cofactor. Here, we demonstrate that Arabidopsis thaliana uses for purpose two separate biosynthetic branches stemming from phenylalanine and tyrosine. Gene network modeling characterization T-DNA mutants indicated acyl-activating enzyme encoded by At4g19010 contributes to biosynthesis ubiquinone specifically phenylalanine. CoA ligase assays verified prefers para-coumarate, ferulate, caffeate as substrates....

Cyanobacterial and plant genomes encode proteins with some similarity to the folate biopterin transporters of trypanosomatid parasite Leishmania. The Synechocystis slr0642 gene product its closest Arabidopsis homolog, At2g32040 product, are representative examples. Both have 12 probable transmembrane domains, protein has a predicted chloroplast transit peptide. When expressed in Escherichia coli pabA pabB or folE, mutants, which unable produce take up folates, modified (truncated fused N...

Folates are essential cofactors for one‐carbon transfer reactions in most living organisms and required the biosynthesis of nucleic acids, amino pantothenate. Unlike plants microorganisms, humans cannot synthesize folates de novo must acquire them from diet, primarily plant foods. However, lack is common vitamin deficiency world has serious health consequences, including increased risk neural tube defects infants, cancers, vascular diseases. Consequently, there much interest engineering with...

It is not known how plants cleave the thioester bond of 1,4-dihydroxy-2-naphthoyl-CoA (DHNA-CoA), a necessary step to form naphthoquinone ring phylloquinone (vitamin K(1) ). In fact, only recently has hydrolysis DHNA-CoA been demonstrated be enzyme driven in vivo, and cognate thioesterase characterized cyanobacterium Synechocystis. With few exceptions certain prokaryotic (Sorangium Opitutus) eukaryotic (Cyanidium, Cyanidioschyzon Paulinella) organisms, orthologs are missing outside...

As metabolic centers, plant organelles participate in maintenance, defense, and signaling. MSH1 is a plant-specific protein involved organellar genome stability mitochondria plastids. Plastid depletion of causes heritable, non-genetic changes development DNA methylation. We investigated the msh1 phenotype using hemi-complementation mutants transgene-null segregants from RNAi suppression lines to sub-compartmentalize effects. show that expression spatially regulated, specifically localizing...

Land plants possess the unique capacity to derive benzenoid moiety of vital respiratory cofactor, ubiquinone (coenzyme Q), from phenylpropanoid metabolism via β-oxidation p-coumarate form 4-hydroxybenzoate. Approximately half in comes this pathway; origin rest remains enigmatic. In study, Phe-[Ring-13C6] feeding assays and gene network reconstructions uncovered a connection between biosynthesis that flavonoids Arabidopsis (Arabidopsis thaliana). Quantification tomato (Solanum lycopersicum)...

Mutation of Arabidopsis thaliana NAD(P)H DEHYDROGENASE C1 (NDC1; At5g08740) results in the accumulation demethylphylloquinone, a late biosynthetic intermediate vitamin K1. Gene coexpression and phylogenomics analyses showed that conserved functional associations occur between K biosynthesis NDC1 homologs throughout prokaryotic eukaryotic lineages. Deletion Synechocystis ndbB, which encodes for one such homolog, resulted same defects as those observed cyanobacterial demethylnaphthoquinone...

Summary Herbivore‐induced plant volatiles act as danger signals to prime defense responses in neighboring plants, yet many cases the mechanism behind this priming is not known. Volatile may be recognized directly by receptors and/or converted into other active compounds. Here we investigate metabolic fate of volatile indole, a known signal maize ( Zea mays ), determine if its conversion compounds could play role defenses. We identified benzoxazinoids major products from indole using heavy...

Flavonols are subclasses of flavonoids, with hundreds structures identified in plants. This chemical diversity primarily arises from glycosylation, where sugars selectively added to the flavonol backbone. While profiles vary across species and organs, evolutionary forces shaping this chemodiversity physiological significance specific glycosides remain a mystery. Here, we reveal that finely tuned transcriptional regulation sugar selectivity glycosyltransferases drive formation distinct organ...

ABSTRACT Plants have evolved the ability to respond a diverse range of biotic and abiotic stresses. Often, combining these stresses multiplies challenge for plants, but occasionally combined stress can induce unexpected synergistic defences. In maize, flooding herbivory induces salicylic acid (SA)‐dependent defence against Spodoptera frugiperda (fall armyworm). this study we used RNAseq metabolic profiling show that flavonoids are involved in maize response herbivory. To assess role...

GTP cyclohydrolase I (GCHI) mediates the first and committing step of pterin branch folate-synthesis pathway. In microorganisms mammals, GCHI is a homodecamer ≈26-kDa subunits. Genomic approaches identified tomato Arabidopsis cDNAs specifying ≈50-kDa proteins containing two GCHI-like domains in tandem indicated that such bimodular occur other plants. Neither domain these has full set residues involved substrate binding catalysis GCHIs. The nevertheless encode functional enzymes, as shown by...

In plants, the last step in synthesis of p-aminobenzoate (PABA) moiety folate remains to be elucidated. Escherichia coli, this is catalyzed by PabC protein, a beta-lyase that converts 4-amino-4-deoxychorismate (ADC)--the reaction product PabA and PabB enzymes--to PABA pyruvate. So far, only known plant enzyme involved ADC synthase, which has fused domains homologous E. coli located plastids. synthase no lyase activity, implying plants have separate lyase. No such any eukaryote. Genomic...

Summary Phylloquinone is the one‐electron carrier at A 1 site of photosystem I, and essential for photosynthesis. Arabidopsis mutants deficient in early steps phylloquinone synthesis do not become autotrophic are seedling lethals, even when grown on sucrose‐supplemented media. Here, we identify acyl‐activating enzyme 14 (AAE14, At1g30520) as o ‐succinylbenzoyl‐coenzyme (OSB‐CoA) ligase acting synthesis. Three aae14 mutant alleles, identified by reverse genetics, were found to be lethal,...

Phylloquinone (vitamin K(1)) is a bipartite molecule that consists of naphthoquinone ring attached to phytyl side chain. The coupling these 2 moieties depends on the hydrolysis CoA thioester 1,4-dihydroxy-2-naphthoate (DHNA), which forms naphthalenoid backbone. It not known whether such enzymatic or chemical. In this study, comparative genomic analyses identified orthologous genes unknown function in most species cyanobacteria cluster with predicted phylloquinone biosynthetic genes. encoded...

Ubiquinone (coenzyme Q) is the generic name of a class lipid-soluble electron carriers formed redox active benzoquinone ring attached to prenyl side chain. The length latter varies among species, and depends upon product specificity trans-long-chain diphosphate synthase that elongates an allylic precursor. In Arabidopsis, this enzyme assumed correspond endoplasmic reticulum-located solanesyl synthase, although direct genetic evidence was lacking. study, reconstruction functional network...

It is a little known fact that plastoquinone-9, vital redox cofactor of photosynthesis, doubles as precursor for the biosynthesis vitamin E analog called plastochromanol-8, physiological significance which has remained elusive. Gene network reconstruction, GFP fusion experiments, and targeted metabolite profiling insertion mutants indicated Arabidopsis possesses two paralogous solanesyl-diphosphate synthases, AtSPS1 (At1g78510) AtSPS2 (At1g17050), assemble side chain plastoquinone-9 in...