| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
|
First published online October 27, 2006; 10.1104/pp.106.087858 Plant Physiology 142:1690-1700 (2006) © 2006 American Society of Plant Biologists OPEN ACCESS ARTICLE
Ethylene Stimulates Nutations That Are Dependent on the ETR1 Receptor1,[W],[OA]Department of Botany, University of Wisconsin, Madison, Wisconsin 53706
Ethylene influences a number of processes in Arabidopsis (Arabidopsis thaliana) through the action of five receptors. In this study, we used high-resolution, time-lapse imaging to examine the long-term effects of ethylene on growing, etiolated Arabidopsis seedlings. These measurements revealed that ethylene stimulates nutations of the hypocotyls with an average delay in onset of over 6 h. The nutation response was constitutive in ctr1-2 mutants maintained in air, whereas ein2-1 mutants failed to nutate when treated with ethylene. Ethylene-stimulated nutations were also eliminated in etr1-7 loss-of-function mutants. Transformation of the etr1-7 mutant with a wild-type genomic ETR1 transgene rescued the nutation phenotype, further supporting a requirement for ETR1. Loss-of-function mutations in the other receptor isoforms had no effect on ethylene-stimulated nutations. However, the double ers1-2 ers2-3 and triple etr2-3 ers2-3 ein4-4 loss-of-function mutants constitutively nutated in air. These results support a model where all the receptors are involved in ethylene-stimulated nutations, but the ETR1 receptor is required and has a contrasting role from the other receptor isoforms in this nutation phenotype. Naphthylphthalamic acid eliminated ethylene-stimulated nutations but had no effect on growth inhibition caused by ethylene, pointing to a role for auxin transport in the nutation phenotype.
The gaseous plant hormone ethylene influences a number of processes in higher plants, such as seed germination, abscission, senescence, fruit ripening, and growth regulation. In etiolated seedlings, ethylene causes a number of changes, including reduced growth of the hypocotyl and root, increased radial expansion of the hypocotyl, altered geotropism, and increased tightening of the apical hook (Abeles et al., 1992  ). Biochemical and mutational studies have identified many components in the ethylene-signaling pathway and led to an increasingly refined model for signal transduction (Guo and Ecker, 2004; Chen et al., 2005).
According to this model, responses to ethylene are mediated by a family of five receptors (ETR1, ERS1, ETR2, EIN4, ERS2) in Arabidopsis (Arabidopsis thaliana) that have homology to bacterial two-component receptors (Chang et al., 1993
Ethylene receptors are believed to transduce signal via Ser/Thr kinase activity in CTR1, which has homology to Raf mitogen-activated protein kinase kinase kinases (Kieber et al., 1993
Whereas a great deal of detail is now available about the effects of ethylene on growth, less is known about the kinetics and dose-response characteristics of other responses to ethylene in etiolated seedlings. In pea (Pisum sativum), stem lateral expansion and growth inhibition appear to occur with similar kinetics (Nee et al., 1978
Ethylene Stimulates Nutations in Etiolated Arabidopsis Seedlings During prolonged treatments with ethylene, we made the observation that ethylene stimulated nutational bending in the root tip (data not shown) and the hypocotyls of etiolated Arabidopsis (Columbia [Col-0]) seedlings growing on a vertically orientated agar plate (Fig. 1 ). We have observed these movements of hypocotyls in over 70 Col-0 wild-type seedlings as well as in the hypocotyls of Wassilewskija (WS) wild-type seedlings (data not shown). When observed from the side, these movements appeared as oscillatory bending movements in the plane of the agar surface with the zone of bending approximately 0.8 mm below the apex of the hook.
By measuring the angle of the bend in each frame of the time series (Fig. 1), we were able to plot the time course of hypocotyl bending to examine the amplitude, period, and delay of nutations. Figure 2A shows examples of the time course of hypocotyl bending for etiolated seedlings treated with 10 µL L–1 ethylene (more examples for this and other conditions and mutants used can be found in Supplemental Data S1). Unless otherwise specified, 5 µM L-  -(2-amino ethoxyvinyl)-Gly (AVG) was included in the agar to block biosynthesis of ethylene by the seedlings. The delay in nutation onset ranged from 2.75 to 10.75 h after addition of ethylene, with the average delay being 6.25 h. This delay did not appear to be dependent on concentrations of ethylene between 3 nL L–1 and 10 µL L–1 (data not shown). Some seedlings nutated in phase with each other even between different experiments or when the onset of nutation was delayed. The initial ethylene-stimulated nutation was almost always in the same direction relative to the opening of the apical hook, with the first bend causing the opening of the hook to face downward in over 90% of the seedlings observed. Nutations could occur quickly with rates of angle change approaching 1.3° min–1 for the higher amplitude oscillations.
To confirm that these movements were not a developmental change or artifact of the experimental system, we followed the growth and movement of etiolated seedlings in the absence of added ethylene. No nutations occurred in the presence of 5 µM AVG, which was included to inhibit ethylene biosynthesis (Fig. 2B). Sometimes, under this condition, very small (approximately 1°) and infrequent hypocotyl bending was observed. It was difficult to determine whether this was true nutational bending, bending due to movement over the agar surface, or due to some other factor. When AVG was omitted, small and frequent nutations were observed with an amplitude of 3.8° ± 2.4° (Fig. 2C). The period of these nutations was 2.6 ± 0.33 h, which is within the range previously reported for etiolated Arabidopsis hypocotyls (Orbovi  and Poff, 1997) and similar to the periods reported for Arabidopsis inflorescences (Hatakeda et al., 2003).
The growth inhibition response to ethylene was similar to that previously reported (Binder et al. 2004a
Figure 3
shows the dose-response relationships for the period and amplitude of ethylene-stimulated nutations in Col-0 wild-type seedlings. The amplitude of hypocotyl nutations at various ethylene concentrations was determined by plotting nutation angle time courses and measuring the change in angle from each of the peaks to the midline of the sine wave. Nutation amplitude varied between 2.5° ± 1.3° and 12° ± 4.7° with a half-maximal response at approximately 40 nL L–1 ethylene. Nutation amplitude showed the largest changes between 10 and 100 nL L–1. The response saturated at 100 nL L–1 with no further increase in nutation amplitude up to 10 µL L–1. Thus, nutation amplitude was slightly more sensitive to ethylene than the long-term growth inhibition response previously reported for etiolated Arabidopsis hypocotyls (Chen and Bleecker, 1995
Most experiments reported here were conducted on vertically orientated plates, which limits the nutational movements to the plane of the agar because the seedling is adhered to the agar surface. Nutational movement patterns can vary between species. Arabidopsis hypocotyls have been reported to nutate in a variety of patterns when not limited by physical constraints (Orbovi and Poff, 1997; Schuster and Engelmann, 1997; Johnsson et al., 1999). To assess the nutation patterns of etiolated Arabidopsis hypocotyls, we imaged Col-0 wild-type seedlings from above while they grew on horizontally oriented plates in the presence of 1 µL L–1 ethylene (Fig. 4
). Of the seven seedlings examined, six nutated in oval to circular patterns. Of these, two nutated clockwise and four nutated counterclockwise. One seedling initially nutated in a pendular side-to-side pattern, then switched to an elliptical, counterclockwise movement. This variation in movement pattern is in general agreement with previous results examining dark-grown (Orbovi and Poff, 1997) and light-grown (Schuster and Engelmann, 1997) Arabidopsis seedling hypocotyls. These results indicate that ethylene at various concentrations can stimulate nutational bending in hypocotyls of etiolated Arabidopsis seedlings.
Mutations in the Ethylene-Signaling Pathway Alter Nutations To confirm that these movements were due to the presence of ethylene, we studied various ethylene-sensing mutants. The constitutive ethylene response mutant, ctr1-2, nutated in air in the presence of AVG (Fig. 5A ). The amplitude of these movements was 8.8° ± 3.0°, whereas the period was 4.2 ± 0.9 h. In contrast, treating the ethylene-insensitive mutant, ein2-1, with 10 µL L–1 ethylene failed to stimulate nutations (Fig. 5B). Similarly, ethylene-insensitive etr1-1 mutants did not nutate (data not shown). The ein2-1 mutants appeared partially agravitropic under the conditions used as evidenced by the prolonged deviation of growth from the gravity vector (90° in the plots) by many seedlings.
We have previously shown that plants lacking the EIN3 and EIL1 transcription factors have a transient growth inhibition response to ethylene (Binder et al., 2004a ). To determine whether these transcription factors are also required for the nutations observed with long ethylene treatments, we treated ein3-1 eil1-1 mutants with ethylene for 22 h (Fig. 5C). These mutants showed a transient growth response to ethylene (data not shown) as reported previously. In 67% of the ein3-1 eil1-1 seedlings measured, ethylene failed to stimulate nutations. In double-mutant seedlings where nutations did occur, the amplitude of movement was small (2.7° ± 0.9°). Some of these mutant seedlings also appeared to be partially agravitropic under the conditions of these experiments. Thus, components of the known ethylene-signaling pathway that lead to growth reduction in the hypocotyl are also involved in nutations stimulated by ethylene.
We initiated experiments to examine the role of individual receptor isoforms in the nutation phenotype using loss-of-function mutants. Previously, it has been shown that single ethylene receptor loss-of-function mutants had little effect on growth or growth inhibition by ethylene, although the etr1-7 loss-of-function mutant showed small, but measurable, growth changes in air and was slightly more sensitive to ethylene (Hua and Meyerowitz, 1998
We examined loss-of-function mutants for the other four receptor isoforms to ascertain their roles in the nutation phenotype. The amplitude of nutations (Fig. 7A ) and the extent of growth inhibition (Fig. 7B) in the presence of ethylene were similar to wild-type controls in both ers1-2 ers2-3 double loss-of-function mutant seedlings and etr2-3 ers2-3 ein4-4 triple loss-of-function mutants. Single loss-of-function mutations in these receptor isoforms had no measurable effect on nutations (data not shown). Because the ers1-2 allele is not a complete loss-of-function mutant while the ers1-3 allele appears to be a complete loss-of-function mutant (Xie et al., 2006 ), we also examined the ers1-3 allele and still observed nutations, suggesting that only ETR1 is required for this phenotype (data not shown). The etr2-3 ers2-3 ein4-4 triple mutant has previously been shown to have constitutive growth inhibition in air, although this growth inhibition was not as severe as the ctr1-2 mutant (Hua and Meyerowitz, 1998; Zhao et al., 2002; O'Malley et al., 2005). We confirmed this constitutive growth inhibition under the conditions used in these experiments (Fig. 7B). This triple mutant also constitutively nutated in air in the presence of AVG with amplitudes somewhat smaller than those of the ctr1-2 mutant (Fig. 7A). The ers1-2 ers2-3 double mutant nutated constitutively in air even though no constitutive growth inhibition has been observed for this mutant (Fig. 7B; Hall and Bleecker, 2003). In air in the presence of AVG, both WS wild-type seedlings (control for the ers1-2 ers2-3 double mutant) and Col-0 wild-type seedlings (control for the etr2-3 ers2-3 ein4-4 triple mutant) grew at similar rates (Fig. 7B) and had small and infrequent hypocotyl bending. Whereas the amplitude of these bends in WS was larger than those of Col-0, they were infrequent in occurrence, making it uncertain whether or not they were true nutations. In the presence of 10 µL L–1 ethylene, the hypocotyls of WS seedlings nutated with a similar amplitude (Fig. 7A) and period (4.1 ± 0.7 h) as Col-0 seedlings.
These results are consistent with a model where all the ethylene receptor isoforms are involved in ethylene-stimulated nutations and the ETR1 receptor is required.
Because nutation has been linked to the plant hormone auxin (Britz and Galston, 1982a
Studies on the function of ethylene receptors have often focused on their role in the regulation of growth at the organ level. These studies indicate that the receptors have at least partially overlapping functions in growth regulation (Hua and Meyerowitz, 1998 ). Whereas the ethylene receptors are structurally related to bacterial two-component receptors that function by His autophosphorylation followed by phosphotransfer to a response regulator (West and Stock, 2001), this mechanism does not appear to be necessary for growth regulation mediated by the ethylene receptors (Wang et al., 2003; Binder et al., 2004b; Qu and Schaller, 2004). In this study, we find that ethylene leads to nutations in hypocotyls of etiolated Arabidopsis seedlings. This stimulation of nutations by ethylene let us study the function of the receptors in a new context. Unlike growth inhibition of the hypocotyl, these nutations require the ETR1 receptor, suggesting a special role for ETR1 in signaling leading to nutations.
Charles and Francis Darwin (1880) described nutations in plants over 125 years ago and these movements have been studied in many plant species, including Arabidopsis (Simmons et al., 1995
There are differences that can be noted between the inhibitory effect of ethylene on hypocotyl growth and stimulation of nutations. The delay for long-term growth inhibition is approximately 1 h after application of ethylene and varies very little (Binder et al., 2004a
We used receptor loss-of-function mutants to study the roles of the various receptor isoforms in ethylene signaling leading to nutations and growth inhibition. The results from these experiments further distinguish the inhibitor effect of ethylene on growth from its effect on nutations. In particular, the etr1-7 loss-of-function mutant, but not other receptor mutants, fails to nutate in the presence of ethylene. Additionally, combinatorial receptor loss-of-function mutants that include loss of ETR1 function also do not nutate. The importance of ETR1 is further strengthened by the fact that transformation of these mutants with a genomic ETR1 transgene rescues the nutation phenotype. In contrast, loss-of-function mutant combinations in the other receptor isoforms lead to constitutive growth inhibition and nutations consistent with a model where all the receptors are involved in the signaling leading to ethylene-stimulated nutations. Previous work suggests that the five receptor isoforms have overlapping, but distinct, roles in signaling that lead to inhibition of growth (Chang et al., 1993
Current models of ethylene signaling posit that receptors stimulate CTR1, which in turn acts as a negative regulator of the response pathway. In these models, ethylene inhibits receptor output, releasing the inhibition by CTR1. Hence, loss of ethylene receptors mimics the action of ethylene and causes constitutive ethylene responses in air. The observation that the etr1-7 mutant fails to nutate is intriguing because this is opposite to what is predicted by these models. One way to reconcile this discrepancy is to invoke a model where ethylene induces differential expression of ETR1 in the zone of bending (see models in Supplemental Data S1). Because eliminating the ETR1 isoform results in lowered growth (Hua and Meyerowitz, 1998
An alternative model to explain the loss of nutations in the etr1-7 mutants proposes that ETR1 has two functions, with one function regulating growth and the other supporting nutations (see Supplemental Data S1 for models). In this model, because the etr1-7 mutation is not leading to constitutive nutations, it appears that ethylene is not acting to inhibit ETR1 to cause nutations as predicted from numerous other studies on ethylene signaling. Two alternative possibilities are that ETR1 is being stimulated by ethylene or that ETR1 is acting independently of ethylene to cause nutations. Whereas an ethylene-independent role in promoting cell elongation has been proposed for ETR1 (Hua and Meyerowitz, 1998
The downstream events by which ethylene causes nutations are not known. Auxin transport inhibitors, such as NPA, have been shown to block nutations in plants, including Arabidopsis (Hatakeda et al., 2003
The role for nutations in etiolated seedlings is not known, although as early as the 1880s it was postulated that these movements could help with penetration through the soil (Darwin and Darwin, 1880
AVG was kindly supplied by Rohm Haas, Inc. and NPA came from Sigma (St. Louis). The etr1-7, etr2-3, ers2-3, and ein4-4 mutants were obtained from Elliot Meyerowitz (Hua and Meyerowitz, 1998 ). The ctr1-2 mutant was from Joseph Kieber (Kieber et al., 1993) and the ein2-1 mutant from Joseph Ecker (Alonso et al., 1999). The ers1-2 mutant was isolated in this lab and described previously (Wang et al., 2003; Hall and Bleecker, 2003). Mutants were in the Col-0 background, except for ers1-2 and ers2-3, which were in the WS background. The etr1-7 ers1-2 and etr1-6 ers2-3 ein4-4 mutants transformed with a genomic ETR1 transgene were generated previously and are described in Wang et al. (2003) and Binder et al. (2004b). The etr1-7 mutant line transformed with genomic the ETR1 transgene was kindly supplied by Eric Schaller and is described in Gamble et al. (2002).
Arabidopsis (Arabidopsis thaliana) seeds were surface sterilized by treatment with 70% alcohol for 30 s, placed on sterile filter paper to dry, and then placed on agar plates containing one-half-strength Murashige and Skoog basal salt mixture, pH 5.7 (Murashige and Skoog, 1962
Seedlings were allowed to grow on vertically orientated plates in darkness to a height of 2 to 4 mm (40–46 h) before the beginning of measurements, as modified from Binder et al. (2004a
Images of hypocotyls of etiolated seedlings were captured using infrared radiation, an electronic camera from either Electrim or Luminera, and custom software as modified from previous studies (Parks and Spalding, 1999
To determine the growth rate of the hypocotyls, one of two methods was used. In one, the height in pixels of each seedling in each frame was analyzed using custom software written by Edgar Spalding in LabVIEW 5.0 (National Instruments) as previously described (Parks and Spalding, 1999 Nutation angles of hypocotyls were measured manually. For each frame in a time series, a line was drawn from the hypocotyl bend to the apical hook (Fig. 1) and a protractor was used to measure the angle of this line. These data were plotted as a function of time. In these plots, 90° indicates growth directly against the gravity vector, whereas angles >90° indicate the opening of the apical hook is aimed down and <90° that the opening is aimed up. Seedlings sometimes grew at vectors other than directly against gravity; this is reflected by the prolonged angle of growth deviating from 90°. Representative seedlings were chosen for figures showing nutation angle over time. The total number (n) of seedlings observed in each condition is shown in each nutation time course. See Supplemental Data S1 for additional nutation time-course plots. Experiments under all conditions were repeated in at least four separate experiments. Because nutations represent a sinusoidal oscillation of bending over time, the nutation amplitude was determined by measuring the change in angle from the peak of each oscillation to the midline of the sine wave. The periodicity of nutations was determined by measuring the time for one complete oscillation for each cycle. We measured this by determining the time between each peak of movement. These measurements were analyzed using t tests with P < 0.05 considered statistically significant.
In two experiments, the shape and direction of nutations were determined by growing plants on horizontal plates and imaging growing seedlings from above. Images were captured every 15 min and the pattern of movement determined by marking the position of the hypocotyl in each frame on transparency film. These traces were then scanned and transferred into Adobe Illustrator.
The following materials are available in the online version of this article.
We thank Edgar Spalding for helpful advice concerning this work, and Caren Chang, Mark Estelle, and Sara Patterson for critiques of early versions of this manuscript. We also thank Eric Schaller for the ers1-3 mutant seeds and the etr1-7 mutant line transformed with genomic ETR1 transgene. Received August 2, 2006; accepted October 17, 2006; published October 27, 2006.
1 This work was supported by the National Science Foundation (grant MCB–0131564 to the late Anthony B. Bleecker, who passed away in January 2005). 
2 Present address: Department of Horticulture, University of Wisconsin, Madison, WI 53706.
3 Present address: Salk Institute for Biological Studies, 10010 North Torrey Pines Rd., La Jolla, CA 92037.
4 Present address: Ceres Inc., 1535 Rancho Conejo Blvd., Thousand Oaks, CA 91320. The author responsible for distribution of materials integral to the findings presented in this article in accordance with the policy described in the Instructions for Authors (www.plantphysiol.org) is: Brad M. Binder (bmbinder{at}wisc.edu).
[W] The online version of this article contains Web-only data.
[OA] Open Access articles can be viewed online without a subscription. www.plantphysiol.org/cgi/doi/10.1104/pp.106.087858 * Corresponding author; e-mail bmbinder{at}wisc.edu; fax 608–262–4743.
Abeles FB (1972) Biosynthesis and mechanism of action of ethylene. Annu Rev Plant Physiol 23: 259–292 Abeles FB, Morgan PW, Saltveit ME Jr (1992) Ethylene in Plant Biology, Ed 2. Academic Press, San Diego Alonso JM, Hirayama T, Roman G, Nourizadeh S, Ecker JR (1999) EIN2, a bifunctional transducer of ethylene and stress responses in Arabidopsis. Science 284: 2148–2152 Alonso JM, Stepanova AN, Solano R, Wisman E, Ferrari S, Ausubel FM, Ecker JR (2003) Five components of the ethylene-response pathway identified in a screen of weak ethylene-insensitive mutants in Arabidopsis. Proc Natl Acad Sci USA 100: 2992–2997 Bangerth F (1974) Interaktionen von Auxin und Äthylen bei der thigmotropen Bewegung der Ranken von Cucumis sativus. Planta 117: 329–338[CrossRef] Berg AR, Peacock K (1992) Growth patterns in nutating and nonnutating sunflower (Helianthus annuus) hypocotyls. Am J Bot 79: 77–85[CrossRef] Binder BM, Mortimore LA, Stepanova AN, Ecker JR, Bleecker AB (2004a) Short term growth responses to ethylene in Arabidopsis seedlings are EIN3 /EIL1 independent. Plant Physiol 136: 2921–2927 Binder BM, O'Malley RC, Wang W, Moore JM, Parks BM, Spalding EP, Bleecker AB (2004b) Arabidopsis seedling growth response and recovery to ethylene: a kinetic analysis. Plant Physiol 136: 2913–2920 Biro RL, Jaffe MJ (1984) Thigmomorphogenesis: ethylene evolution and its role in the changes observed in mechanically perturbed bean plants. Physiol Plant 62: 289–296[CrossRef] Bleecker AB, Estelle MA, Somerville C, Kende H (1988) Insensitivity to ethylene conferred by a dominant mutation in Arabidopsis thaliana. Science 241: 1086–1089 Britz SJ, Galston AW (1982a) Physiology of movements in stems of seedling Pisum sativum L. cv. Alaska. I. Experimental separation of nutation from gravitropism. Plant Physiol 70: 264–271 Britz SJ, Galston AW (1982b) Physiology of movements in stems of seedling Pisum sativum L. cv. Alaska. II. The role of the apical hook and of auxin in nutation. Plant Physiol 70: 1401–1404 Britz SJ, Galston AW (1983) Physiology of movements in stems of seedling Pisum sativum L. cv. Alaska. III. Phototropism in relation to gravitropism, nutation, and growth. Plant Physiol 71: 313–318 Buer CS, Wasteneys GO, Masle J (2003) Ethylene modulates root-wave responses in Arabidopsis. Plant Physiol 132: 1085–1096 Cancel JD, Larsen PB (2002) Loss-of-function mutations in the ethylene receptor ETR1 cause enhanced sensitivity and exaggerated response to ethylene in Arabidopsis. Plant Physiol 129: 1557–1567 Chang C, Kwok SF, Bleecker AB, Meyerowitz EM (1993) Arabidopsis ethylene-response gene ETR1: similarity of product to two-component regulators. Science 262: 539–543 Chao Q, Rothenberg M, Solano R, Roman G, Terzaghi W, Ecker JR (1997) Activation of the ethylene gas response pathway in Arabidopsis by the nuclear protein ETHYLENE-INSENSITIVE3 and related proteins. Cell 89: 1133–1144[CrossRef][Web of Science][Medline] Chen QC, Bleecker AB (1995) Analysis of ethylene signal-transduction kinetics associated with seedling-growth response and chitinase induction in wild-type and mutant Arabidopsis. Plant Physiol 108: 597–607[Abstract] Chen Y-F, Etheridge N, Schaller GE (2005) Ethylene signal transduction. Ann Bot (Lond) 95: 901–915 Clark KL, Larsen PB, Wang X, Chang C (1998) Association of the Arabidopsis CTR1 Raf-like kinase with the ETR1 and ERS1 ethylene receptors. Proc Natl Acad Sci USA 95: 5401–5406 Darwin C, Darwin F (1880) The Power of Movement in Plants. John Murray, London Eisinger WR, Croner L, Taiz L (1983) Ethylene-induced lateral expansion in etiolated pea epicotyls: analysis of kinetics. Plant Physiol 73: 407–412 Folta KM, Spalding EP (2001) Unexpected roles for cryptochrome 2 and phototropin revealed by high-resolution analysis of blue light-mediated hypocotyl growth inhibition. Plant J 26: 471–478[CrossRef][Web of Science][Medline] Furutani I, Watanabe Y, Prieto R, Masukawa M, Suzuki K, Naoi K, Thitamadee S, Shikanai T, Hashimoto T (2000) The SPIRAL genes are required for directional control of cell elongation in Arabidopsis thaliana. Development 127: 4443–4453[Abstract] Gagne JM, Smalle J, Gingerich DJ, Walker JM, Yoo S-D, Yanagisawa S, Vierstra RD (2004) Arabidopsis EIN3-binding F-box 1 and 2 form ubiquitin-protein ligases that repress ethylene action and promote growth by directing EIN3 degradation. Proc Natl Acad Sci USA 101: 6803–6808 Gamble RL, Coonfield ML, Schaller GE (1998) Histidine kinase activity of the ETR1 ethylene receptor from Arabidopsis. Proc Natl Acad Sci USA 95: 7825–7829 Gamble RL, Qu X, Schaller GE (2002) Mutational analysis of the ethylene receptor ETR1. Role of the histidine kinase domain in dominant ethylene insensitivity. Plant Physiol 128: 1428–1438 Gao Z, Chen Y-F, Randlett MD, Zhao X-C, Findell JL, Kieber JJ, Schaller GE (2003) Localization of the Raf-like kinase CTR1 to the endoplasmic reticulum of Arabidopsis through participation in ethylene receptor signaling complexes. J Biol Chem 278: 34725–34732 Goeschl JD, Rappaport L, Pratt HK (1966) Ethylene as a factor regulating the growth of pea epicotyls subjected to physical stress. Plant Physiol 41: 877–884 Guo H, Ecker JR (2003) Plant responses to ethylene gas are mediated by SCFEBF1/EFB2-dependent proteolysis of EIN3 transcription factor. Cell 115: 667–677[CrossRef][Web of Science][Medline] Guo H, Ecker JR (2004) The ethylene signaling pathway: new insights. Curr Opin Plant Biol 7: 40–49[CrossRef][Web of Science][Medline] Hall AE, Bleecker AB (2003) Analysis of combinatorial loss-of-function mutants in the Arabidopsis ethylene receptors reveals that the ers1 etr1 double mutant has severe developmental defects that are EIN2 dependent. Plant Cell 15: 2032–2041 Hall AE, Chen QG, Findell JL, Schaller GE, Bleecker AB (1999) The relationship between ethylene binding and dominant insensitivity conferred by mutant forms of the ETR1 ethylene receptor. Plant Physiol 121: 291–299 Hatakeda Y, Kamada M, Goto N, Fukaki H, Tasaka M, Suge H, Takahashi H (2003) Gravitropic response plays an important role in the nutational movements of the shoots of Pharbitis nil and Arabidopsis thaliana. Physiol Plant 118: 464–473[CrossRef] Hua J, Chang C, Sun Q, Meyerowitz EM (1995) Ethylene insensitivity conferred by Arabidopsis ERS gene. Science 269: 1712–1714 Hua J, Meyerowitz EM (1998) Ethylene responses are negatively regulated by a receptor gene family in Arabidopsis thaliana. Cell 94: 261–271[CrossRef][Web of Science][Medline] Hua J, Sakai H, Nourizadeh S, Chen QG, Bleecker AB, Ecker JR, Meyerowitz EM (1998) EIN4 and ERS2 are members of the putative ethylene receptor gene family in Arabidopsis. Plant Cell 10: 1321–1332 Huang Y, Li H, Hutchison CE, Laskey J, Kieber JJ (2003) Biochemical and functional analysis of CTR1, a protein kinase that negatively regulates ethylene signaling in Arabidopsis. Plant J 33: 221–233[CrossRef][Web of Science][Medline] Hussain A, Black CR, Taylor IB, Roberts JA (1999) Soil compaction. A role for ethylene in regulating leaf expansion and shoot growth in tomato. Plant Physiol 121: 1227–1237 Inoue N, Arase T, Hagiwara M, Manao T, Hyashi T, Ikeda R (1999) Ecological significance of root tip rotation for seedling establishment of Oryza sativa L. Ecol Res 14: 31–38 Johnsson A, Jansen C, Engelmann W, Schuster J (1999) Circumnutations without gravity: a two-oscillator model. J Gravit Physiol 6: 9–12 Kieber JJ, Rothenberg M, Roman G, Feldmann KA, Ecker JR (1993) CTR1, a negative regulator of the ethylene response pathway in Arabidopsis, encodes a member of the Raf family of protein kinases. Cell 72: 427–441[CrossRef][Web of Science][Medline] Knight LI, Crocker W (1913) Toxicity of smoke. Bot Gaz 55: 337–371[CrossRef] Larsen PB, Chang C (2001) The Arabidopsis eer1 mutant has enhanced ethylene responses in the hypocotyl and stem. Plant Physiol 125: 1061–1073 Marinelli B, Gomarasca S, Soave C (1997) A pleiotropic Arabidopsis thaliana mutant with inverted root chirality. Planta 202: 196–205[CrossRef][Web of Science][Medline] Millet B, Melin D, Bonnet B, Ibrahim CA, Mercier J (1984) Rhythmic circumnutation movement of the shoots in Phaseolus vulgaris L. Chronobiol Int 1: 11–19[Medline] Moussatche P, Klee H (2004) Autophosphorylation activity of the Arabidopsis ethylene receptor multigene family. J Biol Chem 279: 48734–48741 Mullen JL, Turk E, Johnson K, Wolverton C, Ishikawa H, Simmons C, Soll D, Evans ML (1998) Root-growth behavior of the Arabidopsis mutant rgr1: roles of gravitropism and circumnutation in the waving/coiling phenomenon. Plant Physiol 118: 1139–1145 Müller-Dieckmann H-J, Grantz AA, Kim S-H (1999) The structure of the signal receiver domain of the Arabidopsis thaliana ethylene receptor ETR1. Structure 7: 1547–1556[Medline] Murashige T, Skoog F (1962) A revised medium for rapid growth and bioassays with tobacco tissue culture. Physiol Plant 15: 473–497[CrossRef] Nee M, Chiu L, Eisinger W (1978) Induction of swelling in pea internode tissue by ethylene. Plant Physiol 62: 902–906 Neljubov D (1901) Uber die horizontale Nutation der Stengel von Pisum sativum und einiger Anderer. Pflanzen Beih Bot Zentralb 10: 128–139 Niinuma K, Someya N, Kimura M, Yamaguchi I, Hamamoro H (2005) Circadian rhythm of circumnutation in inflorescence stems of Arabidopsis. Plant Cell Physiol 46: 1423–1427 O'Malley RC, Rodriguez FI, Esch JJ, Binder BM, O'Donnell P, Klee HJ, Bleecker AB (2005) Ethylene-binding activity, gene-expression levels, and receptor-system output for ethylene-receptor family members from Arabidopsis and tomato. Plant J 41: 651–659[CrossRef][Web of Science][Medline] Orbovi Parks BM, Spalding EP (1999) Sequential and coordinated action of phytochromes A and B during Arabidopsis stem growth revealed by kinetic analysis. Proc Natl Acad Sci USA 96: 14142–14146 Piconese S, Tronelli G, Pippia P, Migliaccio F (2003) Chiral and non-chiral nutations in Arabidopsis roots grown on the random positioning machine. J Exp Bot 54: 1909–1918 Potuschak T, Lechner E, Parmentier Y, Yanagisawa S, Grava S, Koncz C, Genschik P (2003) EIN3-dependent regulation of plant ethylene hormone signaling by two Arabidopsis F box proteins: EBF1 and EBF2. Cell 115: 679–689[CrossRef][Web of Science][Medline] Qu X, Schaller GE (2004) Requirement of the histidine kinase domain for signal transduction by the ethylene receptor ETR1. Plant Physiol 136: 2961–2970 Reinhold L (1967) Induction of coiling in tendrils by auxin and carbon dioxide. Science 158: 791–793 Roberts JA, Hussain Y, Taylor IB, Black CR (2002) Use of mutants to study long-distance signalling. J Exp Bot 53: 45–50 Rodriguez F, Esch J, Hall A, Binder B, Schaller GE, Bleecker AB (1999) A copper cofactor for the ETR1 receptor from Arabidopsis. Science 283: 996–998 Roman G, Lubarsky B, Kieber JJ, Rothenberg M, Ecker JR (1995) Genetic analysis of ethylene signal transduction in Arabidopsis thaliana: five novel mutant loci integrated into a stress response pathway. Genetics 139: 1393–409[Abstract] Sakai H, Hua J, Chen QG, Chang C, Medrano LJ, Bleecker AB, Meyerowitz EM (1998) ETR2 is an ETR1-like gene involved in ethylene signaling in Arabidopsis. Proc Natl Acad Sci USA 95: 5812–5817 Schaller GE, Ladd AN, Lanahan MB, Spanbauer JM, Bleecker AB (1995) The ethylene response mediator ETR1 from Arabidopsis forms a disulfide-linked dimer. J Biol Chem 270: 12526–12530 Schuster J, Engelmann W (1997) Circumnutations of Arabidopsis thaliana seedlings. Biol Rhythm Res 28: 422–440[CrossRef] Shiboaka H (1994) Plant hormone-induced changes in the orientation of cortical microtubules: alterations in the cross-linking between microtubules and the plasma membrane. Annu Rev Plant Physiol Plant Mol Biol 45: 143–150[CrossRef][Web of Science] Simmons C, Soll D, Migliaccio F (1995) Circumnutations and gravitropism cause root waving in Arabidopsis thaliana. J Exp Bot 46: 143–150 Solano R, Stepanova A, Chao Q, Ecker JR (1998) Nuclear events in ethylene signaling: a transcriptional cascade mediated by ETHYLENE-INSENSITIVE3 and ETHYLENE-RESPONSE-FACTOR1. Genes Dev 12: 3703–3714 Steen DA, Chadwick AV (1981) Ethylene effects in pea stem tissue: evidence of microtubule mediation. Plant Physiol 67: 460–466 Takahashi H, Jaffe MJ (1984) Thigmomorphogenesis: the relationship of mechanical perturbation to elicitor-like activity and ethylene production. Physiol Plant 61: 405–411[CrossRef][Medline] Urao T, Miyata S, Yamaguchi-Shinozaki K, Shinozaki K (2000) Possible His to Asp phosphorelay signaling in an Arabidopsis two-component system. FEBS Lett 478: 227–232[CrossRef][Web of Science][Medline] Wang W, Hall AE, O'Malley RC, Bleecker AB (2003) Canonical histidine kinase activity of the transmitter domain of the ETR1 ethylene receptor from Arabidopsis is not required for signal transmission. Proc Natl Acad Sci USA 100: 352–357 West AH, Stock AM (2001) Histidine kinases and response regulator proteins in two-component signaling systems. Trends Biochem Sci 26: 369–376[CrossRef][Web of Science][Medline] Whalen MC (1988) The effect of mechanical impedance on ethylene production by maize roots. Can J Bot 66: 2139–2142 Xie F, Liu Q, Wen C-K (2006) Receptor signal output mediated by the ETR1 N-terminus is primarily subfamily I receptor dependent. Plant Physiol 142: 492–508 Yanagisawa S, Yoo S-D, Sheen J (2003) Differential regulation of EIN3 stability by glucose and ethylene signaling in plants. Nature 425: 521–525[CrossRef][Medline] Zhao X-C, Qu X, Mathews DE, Schaller GE (2002) Effect of ethylene pathway mutations upon expression of the ethylene receptor ETR1 from Arabidopsis. Plant Physiol 130: 1983–1991 Related articles in Plant Physiol.:
This article has been cited by other articles:
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| ASPB Publications | PLANT PHYSIOLOGY® | THE PLANT CELL | |
|---|---|---|---|
TOP
ABSTRACT
RESULTS
). B, Seedlings grew in air for 24 h without ethylene treatment. C, Seedlings were grown in air in the absence of AVG. D, Growth rate for seedlings grown in air (
) are compared to seedlings grown in air for 2 h prior to introducing 10 µL L–1 ethylene (
) indicated by the arrow (
-loop of the receiver domain is thought to be important in molecular interactions. This domain is located next to the conserved Asp-659 and in ETR1 has an atypical orientation compared to other receiver domains that have been structurally characterized (Müller-Dieckmann et al., 1999
