Evidence for cross-pathway regulation of metabolic gene expression in plants.

Guyer, David; Patton, David A.; Ward, Eric

doi:10.1073/pnas.92.11.4997

Cited by 84 publications

(61 citation statements)

References 35 publications

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“…The dynamic changes in the concentrations of numerous other amino acids support the notion of cross-pathway regulation of different amino acid biosynthesis pathways in plants. This mechanism has been shown to exist in yeast (Hinnebusch, 1992) and may also cause a general deregulation of free amino acid content in plants if one amino acid is not produced sufficiently (Guyer et al, 1995;Noutoshi et al, 2005). Indeed, a general amino Figure 9.…”

Section: Mutation Of Tup5 Causes a Reduction Of Arg Content And Has Pmentioning

confidence: 99%

The ArabidopsisTUMOR PRONE5Gene Encodes an Acetylornithine Aminotransferase Required for Arginine Biosynthesis and Root Meristem Maintenance in Blue Light

et al. 2013

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Arginine is an essential amino acid necessary for protein synthesis and is also a nitrogen storage compound. The genes encoding the enzymes of arginine biosynthesis in plants are not well characterized and have mainly been predicted from homologies to bacterial and fungal genes. We report the cloning and characterization of the TUMOR PRONE5 (TUP5) gene of Arabidopsis (Arabidopsis thaliana) encoding an acetylornithine aminotransferase (ACOAT), catalyzing the fourth step of arginine biosynthesis. The free arginine content was strongly reduced in the chemically induced recessive mutant tup5-1, root growth was restored by supplementation with arginine and its metabolic precursors, and a yeast (Saccharomyces cerevisiae) ACOAT mutant was complemented by TUP5. Two null alleles of TUP5 caused a reduced viability of gametes and embryo lethality, possibly caused by insufficient Arg supply from maternal tissue. TUP5 expression is positively regulated by light, and a TUP5-green fluorescent protein was localized in chloroplasts. tup5-1 has a unique light-dependent short root phenotype. Roots of light-grown tup5-1 seedlings switch from indeterminate growth to determinate growth with arresting cell production and an exhausted root apical meristem. The inhibitory activity was specific for blue light, and the inhibiting light was perceived by the root. Thus, tup5-1 reveals a novel role of amino acids and blue light in regulating root meristem function.

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Section: Mutation Of Tup5 Causes a Reduction Of Arg Content And Has Pmentioning

confidence: 99%

The ArabidopsisTUMOR PRONE5Gene Encodes an Acetylornithine Aminotransferase Required for Arginine Biosynthesis and Root Meristem Maintenance in Blue Light

et al. 2013

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“…NDPK Ia mRNA is strongly stimulated after UV-B light irradiation of Arabidopsis seedlings, and there is an obvious correlation to the expression of HDH, the Arabidopsis homologue of yeast HIS4. Similarly to yeast, induction of histidine biosynthetic genes in Arabidopsis occurs not only following exposure to UV light but also during starvation (57), providing additional proof of the similarity between the systems.…”

Section: Discussionmentioning

confidence: 88%

UV-responsive Genes of Arabidopsis Revealed by Similarity to the Gcn4-mediated UV Response in Yeast

Zimmermann

Baumann

Jaekel

et al. 1999

Journal of Biological Chemistry

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A UV response that involves the Ras proteins and AP-1 transcription factors has recently been described in mammals and yeast. To test whether an equivalent response exists in plants, we monitored the expression of Arabidopsis histidinol dehydrogenase gene (HDH), a homologue of the yeast HIS4 gene, which is strongly induced by UV light and is a target of the transcriptional activator Gcn4. We show that HDH mRNA levels increase specifically in response to UV-B light. Only small increases were detected upon exposure to other wavelengths. To isolate plant genes involved in this UV response, a gcn4 mutant was transfected with an Arabidopsis thaliana cDNA library. A new type of nucleotide diphosphate kinase (NDPK Ia) with a significant homology to the human tumor suppressor protein Nm23 rescued the gcn4 phenotype. NDPK Ia specifically binds to the HIS4 promoter in vitro and induces HIS4 transcription in yeast. In Arabidopsis, the NDPK Ia protein is located in the nucleus and cytosol. Expression studies in seedlings revealed that the level of NDPK Ia mRNA, like that of HDH, increases in response to UV-B light. It appears that NDPK Ia and HDH are components of a novel UV-responsive pathway in A. thaliana.

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“…His plays an essential role in plant reproduction, growth, chelation, and transport of metal ions. Blocking His biosynthesis in Arabidopsis leaves, for example, causes increased expression of several genes involved in other amino acid synthesis pathways and affects the levels of several FAAs (Guyer et al, 1995;Stepansky and Leustek, 2006;Ingle, 2011). Nevertheless, the regulation of His metabolism as well as its entire catabolic pathway remain unclear (Stepansky and Leustek, 2006;Ingle, 2011).…”

Section: Discussionmentioning

confidence: 99%

“…Still, the genetic control of FAA metabolism in seed remains poorly understood. One reason is that FAA metabolism is tightly intertwined with essential cellular processes in plants, and manipulating FAA levels can have strong deleterious, pleiotropic effects on the entire system (Guyer et al, 1995;Galili, 2011;Ingle, 2011;Pratelli and Pilot, 2014). For example, increasing Lys and Thr inhibits the activity of Asp kinase via a feedback inhibition loop (Clark and Lu, 2015).…”

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confidence: 99%

Network-Guided GWAS Improves Identification of Genes Affecting Free Amino Acids

et al. 2016

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Amino acids are essential for proper growth and development in plants. Amino acids serve as building blocks for proteins but also are important for responses to stress and the biosynthesis of numerous essential compounds. In seed, the pool of free amino acids (FAAs) also contributes to alternative energy, desiccation, and seed vigor; thus, manipulating FAA levels can significantly impact a seed's nutritional qualities. While genome-wide association studies (GWAS) on branched-chain amino acids have identified some regulatory genes controlling seed FAAs, the genetic regulation of FAA levels, composition, and homeostasis in seeds remains mostly unresolved. Hence, we performed GWAS on 18 FAAs from a 313-ecotype Arabidopsis (Arabidopsis thaliana) association panel. Specifically, GWAS was performed on 98 traits derived from known amino acid metabolic pathways (approach 1) and then on 92 traits generated from an unbiased correlation-based metabolic network analysis (approach 2), and the results were compared. The latter approach facilitated the discovery of additional novel metabolic interactions and singlenucleotide polymorphism-trait associations not identified by the former approach. The most prominent network-guided GWAS signal was for a histidine (His)-related trait in a region containing two genes: a cationic amino acid transporter (CAT4) and a polynucleotide phosphorylase resistant to inhibition with fosmidomycin. A reverse genetics approach confirmed CAT4 to be responsible for the natural variation of His-related traits across the association panel. Given that His is a semiessential amino acid and a potent metal chelator, CAT4 orthologs could be considered as candidate genes for seed quality biofortification in crop plants.Free amino acids (FAAs) play a pivotal role in the central metabolism of plants. FAAs serve as building blocks for protein synthesis and also are precursors for osmolytes, alternative energy, hormones, and key secondary metabolites (Rai, 2002; Araújo et al., 2010;Tzin and Galili, 2010; Angelovici et al., 2011). Studies of both developing and germinating seeds also have implicated FAAs in proper seed development and germination (Angelovici et al., 2010;Galili and Amir, 2013). Still, the genetic control of FAA metabolism in seed remains poorly understood. One reason is that FAA metabolism is tightly intertwined with essential cellular processes in plants, and manipulating FAA levels can have strong deleterious, pleiotropic effects on the entire system (Guyer et al., 1995;Galili, 2011;Ingle, 2011;Pratelli and Pilot, 2014). For example, increasing Lys and Thr inhibits the activity of Asp kinase via a feedback inhibition loop (Clark and Lu, 2015). At high concentrations, this inhibition can lead to starvation of a downstream metabolic product, Met, which inhibits plant growth (Bright et al., 1982;Rognes et al., 1983;Heremans and Jacobs, 1995). In addition, several amino acid catabolic products, such as those emanating from branched-chain amino acids (BCAAs) or Lys degradation pathways, can be chan...

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Evidence for cross-pathway regulation of metabolic gene expression in plants.

Cited by 84 publications

References 35 publications

The ArabidopsisTUMOR PRONE5Gene Encodes an Acetylornithine Aminotransferase Required for Arginine Biosynthesis and Root Meristem Maintenance in Blue Light

The ArabidopsisTUMOR PRONE5Gene Encodes an Acetylornithine Aminotransferase Required for Arginine Biosynthesis and Root Meristem Maintenance in Blue Light

UV-responsive Genes of Arabidopsis Revealed by Similarity to the Gcn4-mediated UV Response in Yeast

Network-Guided GWAS Improves Identification of Genes Affecting Free Amino Acids

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