Ethylene is involved in nitrate-dependent root growth and branching in Arabidopsis thaliana.

*Here, we investigated the role of ethylene in high nitrate-induced change in root development in Arabidopsis thaliana using wild types and mutants defective in ethylene signaling (etr1, ein2) and nitrate transporters (chl1, nrt2.1). *The length and number of visible lateral roots (LRs) were reduced upon exposure of wild-type seedlings grown on low (0.1 mM) to high nitrate concentration (10 mM). There was a rapid burst of ethylene production upon exposure to high nitrate concentration. *Ethylene synthesis antagonists, cobalt (Co(2+)) and aminoethoxyvinylglycine (AVG), mitigated the inhibitory effect of high nitrate concentration on lateral root growth. The etr1-3 and ein2-1 mutants exhibited less reductions in LR length and number than wild-type plants in response to high nitrate concentration. Expression of nitrate transporters AtNRT1.1 and AtNRT2.1 was upregulated and downregulated in response to high nitrate concentration, respectively. A similar upregulation and downregulation of AtNRT1.1 and AtNRT2.1 was observed by ethylene synthesis precursor aminocyclopropane carboxylic acid (ACC) and AVG in low and high nitrate concentration, respectively. Expression of AtNRT1.1 and AtNRT2.1 became insensitive to high nitrate concentration in etr1-3 and ein2-1 plants. *These findings highlight the regulatory role that ethylene plays in high nitrate concentration-regulated LR development by modulating nitrate transporters.

[1]  D. Gibbs,et al.  Branching out in new directions: the control of root architecture by lateral root formation. , 2008, The New phytologist.

[2]  J. G. Dubrovsky,et al.  Ethylene-auxin interactions regulate lateral root initiation and emergence in Arabidopsis thaliana. , 2008, The Plant journal : for cell and molecular biology.

[3]  Fusuo Zhang,et al.  Inhibition of maize root growth by high nitrate supply is correlated with reduced IAA levels in roots. , 2008, Journal of plant physiology.

[4]  B. Forde,et al.  Nitrate signalling mediated by the NRT1.1 nitrate transporter antagonises L-glutamate-induced changes in root architecture. , 2008, The Plant journal : for cell and molecular biology.

[5]  M. Ivanchenko,et al.  Ethylene regulates lateral root formation and auxin transport in Arabidopsis thaliana , 2008, The Plant journal : for cell and molecular biology.

[6]  J. Lecourt,et al.  Elongation Changes of Exploratory and Root Hair Systems Induced by Aminocyclopropane Carboxylic Acid and Aminoethoxyvinylglycine Affect Nitrate Uptake and BnNrt2.1 and BnNrt1.1 Transporter Gene Expression in Oilseed Rape[W] , 2008, Plant Physiology.

[7]  T. Desnos.  Root branching responses to phosphate and nitrate. , 2008, Current opinion in plant biology.

[8]  Q. Tian,et al.  Nitric oxide is involved in nitrate-induced inhibition of root elongation in Zea mays. , 2007, Annals of botany.

[9]  Mingui Zhao,et al.  Aluminum-induced ethylene production is associated with inhibition of root elongation in Lotus japonicus L. , 2007, Plant & cell physiology.

[10]  Rishikesh Bhalerao,et al.  Ethylene Upregulates Auxin Biosynthesis in Arabidopsis Seedlings to Enhance Inhibition of Root Cell Elongation[W] , 2007, The Plant Cell Online.

[11]  K. Ljung,et al.  Ethylene Regulates Root Growth through Effects on Auxin Biosynthesis and Transport-Dependent Auxin Distribution[W] , 2007, The Plant Cell Online.

[12]  J. Alonso,et al.  Multilevel Interactions between Ethylene and Auxin in Arabidopsis Roots[W] , 2007, The Plant Cell Online.

[13]  D. Pilbeam,et al.  Signalling mechanisms underlying the morphological responses of the root system to nitrogen in Arabidopsis thaliana. , 2007, Journal of experimental botany.

[14]  Karen S. Osmont,et al.  Hidden branches: developments in root system architecture. , 2007, Annual review of plant biology.

[15]  D. Van Der Straeten,et al.  Reciprocal influence of ethylene and gibberellins on response-gene expression in Arabidopsis thaliana , 2007, Planta.

[16]  P. Tillard,et al.  The Arabidopsis NRT1.1 transporter participates in the signaling pathway triggering root colonization of nitrate-rich patches , 2006, Proceedings of the National Academy of Sciences.

[17]  R. O’Malley,et al.  Ethylene Stimulates Nutations That Are Dependent on the ETR1 Receptor1[W][OA] , 2006, Plant Physiology.

[18]  Brian G Forde,et al.  Nitrogen regulation of root branching. , 2006, Annals of botany.

[19]  R. Pierik,et al.  The Janus face of ethylene: growth inhibition and stimulation. , 2006, Trends in Plant Science.

[20]  G. Muday,et al.  Ethylene Modulates Flavonoid Accumulation and Gravitropic Responses in Roots of Arabidopsis1[W] , 2006, Plant Physiology.

[21]  P. Tillard,et al.  A Central Role for the Nitrate Transporter NRT2.1 in the Integrated Morphological and Physiological Responses of the Root System to Nitrogen Limitation in Arabidopsis1 , 2006, Plant Physiology.

[22]  Fusuo Zhang,et al.  Possible Involvement of Cytokinin in Nitrate-mediated Root Growth in Maize , 2005, Plant and Soil.

[23]  F. Daniel-Vedele,et al.  The putative high-affinity nitrate transporter NRT2.1 represses lateral root initiation in response to nutritional cues. , 2005, Proceedings of the National Academy of Sciences of the United States of America.

[24]  Anna N. Stepanova,et al.  A Link between Ethylene and Auxin Uncovered by the Characterization of Two Root-Specific Ethylene-Insensitive Mutants in Arabidopsis , 2005, The Plant Cell Online.

[25]  Yi-feng Chen,et al.  Ethylene signal transduction. , 2005, Annals of botany.

[26]  Brad M. Binder,et al.  Ethylene-binding activity, gene expression levels, and receptor system output for ethylene receptor family members from Arabidopsis and tomato. , 2005, The Plant journal : for cell and molecular biology.

[27]  J. Alonso,et al.  The Ethylene Signaling Pathway , 2004, Science.

[28]  A. Theologis,et al.  Unique and Overlapping Expression Patterns among the Arabidopsis 1-Amino-Cyclopropane-1-Carboxylate Synthase Gene Family Members1[w] , 2004, Plant Physiology.

[29]  Cécile Fizames,et al.  Transcript Profiling in the chl1-5 Mutant of Arabidopsis Reveals a Role of the Nitrate Transporter NRT1.1 in the Regulation of Another Nitrate Transporter, NRT2.1w⃞ , 2004, The Plant Cell Online.

[30]  D. Schachtman,et al.  Hydrogen peroxide mediates plant root cell response to nutrient deprivation. , 2004, Proceedings of the National Academy of Sciences of the United States of America.

[31]  F. Daniel-Vedele,et al.  Disruption of the nitrate transporter genes AtNRT2.1 and AtNRT2.2 restricts growth at low external nitrate concentration , 2004, Planta.

[32]  J. Tumlinson,et al.  Nitrogen Deficiency Increases Volicitin-Induced Volatile Emission, Jasmonic Acid Accumulation, and Ethylene Sensitivity in Maize1 , 2003, Plant Physiology.

[33]  H. Sakakibara.  Nitrate-specific and cytokinin-mediated nitrogen signaling pathways in plants , 2003, Journal of Plant Research.

[34]  D. Inzé,et al.  An abscisic acid-sensitive checkpoint in lateral root development of Arabidopsis. , 2003, The Plant journal : for cell and molecular biology.

[35]  B. Forde.  Local and long-range signaling pathways regulating plant responses to nitrate. , 2002, Annual review of plant biology.

[36]  Joseph R Ecker,et al.  Ethylene Biosynthesis and Signaling Networks Article, publication date, and citation information can be found at www.plantcell.org/cgi/doi/10.1105/tpc.001768. , 2002, The Plant Cell Online.

[37]  Luis Herrera-Estrella,et al.  Phosphate Availability Alters Architecture and Causes Changes in Hormone Sensitivity in the Arabidopsis Root System1 , 2002, Plant Physiology.

[38]  Rongchen Wang,et al.  The Arabidopsis dual-affinity nitrate transporter gene AtNRT1.1 (CHL1) is regulated by auxin in both shoots and roots. , 2002, Journal of experimental botany.

[39]  H. Leyser,et al.  Nitrate and phosphate availability and distribution have different effects on root system architecture of Arabidopsis. , 2002, The Plant journal : for cell and molecular biology.

[40]  C. Foyer,et al.  ABA plays a central role in mediating the regulatory effects of nitrate on root branching in Arabidopsis. , 2002, The Plant journal : for cell and molecular biology.

[41]  W. Schmidt.  From faith to fate : Ethylene signaling in morphogenic responses to P and Fe deficiency , 2001 .

[42]  D. Kamboj,et al.  Ethylene evolution and antioxidant defence mechanism in Cicer arietinum roots in the presence of nitrate and aminoethoxyvinylglycine , 2000 .

[43]  P. Gresshoff,et al.  Inoculation and nitrate alter phytohormone levels in soybean roots: differences between a supernodulating mutant and the wild type , 2000, Planta.

[44]  B. Forde,et al.  Nitrate transporters in plants: structure, function and regulation. , 2000, Biochimica et biophysica acta.

[45]  J. Ecker,et al.  EIN2, a bifunctional transducer of ethylene and stress responses in Arabidopsis. , 1999, Science.

[46]  P W Barlow,et al.  Dual pathways for regulation of root branching by nitrate. , 1999, Proceedings of the National Academy of Sciences of the United States of America.

[47]  C. Ye,et al.  Two Arabidopsis mutants that overproduce ethylene are affected in the posttranscriptional regulation of 1-aminocyclopropane-1-carboxylic acid synthase. , 1999, Plant physiology.

[48]  B. Forde,et al.  An Arabidopsis MADS box gene that controls nutrient-induced changes in root architecture. , 1998, Science.

[49]  N. Crawford,et al.  The herbicide sensitivity gene CHL1 of arabidopsis encodes a nitrate-inducible nitrate transporter , 1993, Cell.

[50]  S. Yang,et al.  Inactivation of 1-Aminocyclopropane-1-Carboxylate Synthase by l-Vinylglycine as Related to the Mechanism-Based Inactivation of the Enzyme by S-Adenosyl-l-Methionine. , 1989, Plant physiology.

[51]  M. Bevan,et al.  GUS fusions: beta‐glucuronidase as a sensitive and versatile gene fusion marker in higher plants. , 1987, The EMBO journal.

[52]  S. Yang,et al.  Inhibition of ethylene production by cobaltous ion. , 1976, Plant physiology.

[53]  S. Yang,et al.  Inhibition of ethylene production by cobaltous ion. [Beans, apples] , 1976 .

[54]  B. Usadel,et al.  Genome-wide reprogramming of metabolism and regulatory networks of Arabidopsis in response to phosphorus. , 2007, Plant, cell & environment.

[55]  J. Malamy,et al.  Intrinsic and environmental response pathways that regulate root system architecture. , 2005, Plant, cell & environment.

[56]  C. Fizames,et al.  Transcript Profiling in the chl 1-5 Mutant of Arabidopsis Reveals a Role of the Nitrate Transporter NRT 1 . 1 in the Regulation of Another Nitrate Transporter , NRT 2 , 2004 .

[57]  B. Forde,et al.  Regulation of Arabidopsis root development by nitrate availability. , 2000, Journal of experimental botany.

[58]  F. Ligero,et al.  Nitrate‐induced ethylene biosynthesis and the control of nodulation in alfalfa , 1998 .

[59]  P. Benfey,et al.  Organization and cell differentiation in lateral roots of Arabidopsis thaliana. , 1997, Development.