Analysis of the rrl3 Mutants Reveals the Importance of Arginine Biosynthesis in the Maintenance of Root Apical Meristem in Rice

We characterized reduced root length3(rrl3) mutantsof rice that exhibit a short-root phenotype under conditions producing mechanical impediments to growth, such as aerated water culture medium. The mutants were not able to maintain the quiescent center (QC) identity and produced disorganized root apical meristem (RAM) under aeration because of impaired cell division. A map-based cloning approach showed that RRL3 encodes carbamoyl phosphate synthetase (CPS) which is thought to be required for the conversion of ornithine into citrulline during arginine biosynthesis. The RRL3 gene is expressed highly at the root tip area that includes the root cap and division zone. The RRL3 gene expression level was greatly affected by aeration treatment, indicating that the spatiotemporal expression of the RRL3 gene with respect to the aeration is important for the maintenance of RAM. Furthermore, the application of citrulline and arginine could rescue the root phenotype, which implied that arginine biosynthesis was impaired in the rrl3-1 mutant. These results suggest that the RRL3 regulated arginine biosynthesis is important for the maintenance of RAM organization in the presence of mechanical impediments.

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Malate-dependent Fe accumulation is a critical checkpoint in the root developmental response to low phosphate

10.1101/095497 ◽

2016 ◽

Author(s):

Javier Mora-Macías ◽

Jonathan Odilón Ojeda-Rivera ◽

Dolores Gutiérrez-Alanís ◽

Lenin Yong-Villalobos ◽

Araceli Oropeza-Aburto ◽

...

Keyword(s):

Crop Production ◽

Apical Meristem ◽

Root System Architecture ◽

Root Apical Meristem ◽

Root Tip ◽

Short Root ◽

Agricultural Ecosystems ◽

Developmental Program ◽

Pi Starvation ◽

Malate Transporter

AbstractLow phosphate (Pi) availability constrains plant development and crop production in both natural and agricultural ecosystems. When Pi is scarce, modifications of root system architecture (RSA) enhance soil exploration ability and can lead to an increase in Pi uptake. In Arabidopsis, an iron-dependent determinate developmental program that induces premature differentiation in the root apical meristem (RAM) begins when the root tip contacts low Pi media, resulting in a short-root phenotype. However, the mechanisms that enable the regulation of root growth in response to Pi-limiting conditions remain largely unknown. Cellular, genomic and transcriptomic analysis of low-Pi insensitive mutants revealed that the malate-exudation related genes SENSITIVE TO PROTON RHIZOTOXICITY (STOP1) and ALUMINUM ACTIVATED MALATE TRANSPORTER 1 (ALMT1) represent a critical checkpoint in the root developmental response to Pi starvation in Arabidopsis thaliana.

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Malate-dependent Fe accumulation is a critical checkpoint in the root developmental response to low phosphate

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1701952114 ◽

2017 ◽

Vol 114 (17) ◽

pp. E3563-E3572 ◽

Cited By ~ 90

Author(s):

Javier Mora-Macías ◽

Jonathan Odilón Ojeda-Rivera ◽

Dolores Gutiérrez-Alanís ◽

Lenin Yong-Villalobos ◽

Araceli Oropeza-Aburto ◽

...

Keyword(s):

Primary Root ◽

Root System Architecture ◽

Root Apical Meristem ◽

Root Tip ◽

Al Tolerance ◽

Short Root ◽

Meristematic Cells ◽

Isolation And Characterization ◽

Root Response ◽

Primary Root Growth

Low phosphate (Pi) availability constrains plant development and seed production in both natural and agricultural ecosystems. When Pi is scarce, modifications of root system architecture (RSA) enhance the soil exploration ability of the plant and lead to an increase in Pi uptake. In Arabidopsis, an iron-dependent mechanism reprograms primary root growth in response to low Pi availability. This program is activated upon contact of the root tip with low-Pi media and induces premature cell differentiation and the arrest of mitotic activity in the root apical meristem, resulting in a short-root phenotype. However, the mechanisms that regulate the primary root response to Pi-limiting conditions remain largely unknown. Here we report on the isolation and characterization of two low-Pi insensitive mutants (lpi5 and lpi6), which have a long-root phenotype when grown in low-Pi media. Cellular, genomic, and transcriptomic analysis of low-Pi insensitive mutants revealed that the genes previously shown to underlie Arabidopsis Al tolerance via root malate exudation, known as SENSITIVE TO PROTON RHIZOTOXICITY (STOP1) and ALUMINUM ACTIVATED MALATE TRANSPORTER 1 (ALMT1), represent a critical checkpoint in the root developmental response to Pi starvation in Arabidopsis thaliana. Our results also show that exogenous malate can rescue the long-root phenotype of lpi5 and lpi6. Malate exudation is required for the accumulation of Fe in the apoplast of meristematic cells, triggering the differentiation of meristematic cells in response to Pi deprivation.

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Carbamoyl phosphate synthetase subunit Cpa1 interacting with Dut1, controls development, arginine biosynthesis, and pathogenicity of Colletotrichum gloeosporioides

Fungal Biology ◽

10.1016/j.funbio.2020.10.009 ◽

2020 ◽

Author(s):

Qingqun Tan ◽

Xuanzhu Zhao ◽

Haiyong He ◽

Junxiang Zhang ◽

Tuyong Yi

Keyword(s):

Colletotrichum Gloeosporioides ◽

Carbamoyl Phosphate Synthetase ◽

Arginine Biosynthesis ◽

Carbamoyl Phosphate

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The Pyrimidine Operon pyrRPB-carA fromLactococcus lactis

Journal of Bacteriology ◽

10.1128/jb.183.9.2785-2794.2001 ◽

2001 ◽

Vol 183 (9) ◽

pp. 2785-2794 ◽

Cited By ~ 45

Author(s):

Jan Martinussen ◽

Jette Schallert ◽

Birgit Andersen ◽

Karin Hammer

Keyword(s):

Mutational Analysis ◽

Regulatory Gene ◽

Regulatory Protein ◽

Small Subunit ◽

Transcriptional Level ◽

Carbamoyl Phosphate Synthetase ◽

Arginine Biosynthesis ◽

Carbamoyl Phosphate ◽

Biosynthetic Genes ◽

Membrane Bound

ABSTRACT The four genes pyrR, pyrP, pyrB, and carAwere found to constitute an operon in Lactococcus lactissubsp. lactis MG1363. The functions of the different genes were established by mutational analysis. The first gene in the operon is the pyrimidine regulatory gene, pyrR, which is responsible for the regulation of the expression of the pyrimidine biosynthetic genes leading to UMP formation. The second gene encodes a membrane-bound high-affinity uracil permease, required for utilization of exogenous uracil. The last two genes in the operon, pyrBand carA, encode pyrimidine biosynthetic enzymes; aspartate transcarbamoylase (pyrB) is the second enzyme in the pathway, whereas carbamoyl-phosphate synthetase subunit A (carA) is the small subunit of a heterodimeric enzyme, catalyzing the formation of carbamoyl phosphate. The carAgene product is shown to be required for both pyrimidine and arginine biosynthesis. The expression of the pyrimidine biosynthetic genes including the pyrRPB-carA operon is subject to control at the transcriptional level, most probably by an attenuator mechanism in which PyrR acts as the regulatory protein.

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Arginine synthesis by hepatomas in vitro. I. The requirements for cell growth in medium containing ornithine in place of arginine and the isolation and characterization of variant hepatomas auxotrophic for arginine

Journal of Cell Science ◽

10.1242/jcs.68.1.285 ◽

1984 ◽

Vol 68 (1) ◽

pp. 285-303 ◽

Cited By ~ 2

Author(s):

S.J. Goss

Keyword(s):

Cell Growth ◽

The Other ◽

Gene Products ◽

Carbamoyl Phosphate Synthetase ◽

Arginine Biosynthesis ◽

Carbamoyl Phosphate ◽

Isolation And Characterization ◽

Ornithine Transcarbamoylase

Cell growth in ‘ornithine-medium’ requires the expression of two liver-specific genes, those for ornithine transcarbamoylase (OTC) and carbamoyl phosphate synthetase I (CPS-I). CPS-II appears unable to replace CPS-I in this system. The need for N-acetylglutamate (to activate CPS-I) can be met, at least in part, by providing it in the medium. The other gene products involved in arginine biosynthesis are probably all ubiquitous (i.e. not tissue-specific). In an attempt to study the factors responsible for the expression of liver-specific genes, variant hepatomas are isolated that have lost the ability to grow in ornithine-medium. Two classes of ‘orn-’ variants are identified: unstable variants that require dexamethasone for adequate CPS-I production, and ‘stable’ variants that have lost many liver-specific traits. Studies on one stable variant show that it can revert (though rarely), and that it regains its various liver-specific traits in a non-coordinate fashion.

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In Lactobacillus plantarum, Carbamoyl Phosphate Is Synthesized by Two Carbamoyl-Phosphate Synthetases (CPS): Carbon Dioxide Differentiates the Arginine-Repressed from the Pyrimidine-Regulated CPS

Journal of Bacteriology ◽

10.1128/jb.182.12.3416-3422.2000 ◽

2000 ◽

Vol 182 (12) ◽

pp. 3416-3422 ◽

Cited By ~ 18

Author(s):

Hervé Nicoloff ◽

Jean-Claude Hubert ◽

Françoise Bringel

Keyword(s):

Carbon Dioxide ◽

Lactic Acid ◽

Lactic Acid Bacterium ◽

Lactobacillus Plantarum ◽

Bicarbonate Level ◽

Carbamoyl Phosphate Synthetase ◽

Wild Type ◽

Arginine Biosynthesis ◽

Carbamoyl Phosphate ◽

Double Deletion

ABSTRACT Carbamoyl phosphate (CP) is an intermediate in pyrimidine and arginine biosynthesis. Carbamoyl-phosphate synthetase (CPS) contains a small amidotransferase subunit (GLN) that hydrolyzes glutamine and transfers ammonia to the large synthetase subunit (SYN), where CP biosynthesis occurs in the presence of ATP and CO2.Lactobacillus plantarum, a lactic acid bacterium, harbors a pyrimidine-inhibited CPS (CPS-P; Elagöz et al., Gene 182:37–43, 1996) and an arginine-repressed CPS (CPS-A). Sequencing has shown that CPS-A is encoded by carA (GLN) and carB (SYN). Transcriptional studies have demonstrated that carB is transcribed both monocistronically and in the carABarginine-repressed operon. CP biosynthesis in L. plantarumwas studied with three mutants (ΔCPS-P, ΔCPS-A, and double deletion). In the absence of both CPSs, auxotrophy for pyrimidines and arginine was observed. CPS-P produced enough CP for both pathways. In CO2-enriched air but not in ordinary air, CPS-A provided CP only for arginine biosynthesis. Therefore, the uracil sensitivity observed in prototrophic wild-type L. plantarum without CO2 enrichment may be due to the low affinity of CPS-A for its substrate CO2 or to regulation of the CP pool by the cellular CO2/bicarbonate level.

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