Gravitropism in Higher Plants1

Chen, Rujin; Rosen, Elizabeth; Masson, Patrick

doi:10.1104/pp.120.2.343

Cited by 226 publications

(130 citation statements)

References 64 publications

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“…The Cholodny-Went hypothesis suggests that asymmetric growth, whether the result of phototropic or gravitropic stimuli, occurs as a result of asymmetric auxin distribution (for review, see Trewavas, 1992;Chen et al, 1999;Muday, 2001). The gps mutants respond normally to both phototropic and gravitropic stimuli at RT.…”

Section: Discussionmentioning

confidence: 99%

Mutations in the Gravity Persistence Signal Loci in Arabidopsis Disrupt the Perception and/or Signal Transduction of Gravitropic Stimuli

et al. 2002

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Gravity plays a fundamental role in plant growth and development, yet little is understood about the early events of gravitropism. To identify genes affected in the signal perception and/or transduction phase of the gravity response, a mutant screen was devised using cold treatment to delay the gravity response of inflorescence stems of Arabidopsis. Inflorescence stems of Arabidopsis show no response to gravistimulation at 4°C for up to 3 h. However, when gravistimulated at 4°C and then returned to vertical at room temperature (RT), stems bend in response to the previous, horizontal gravistimulation (H. Fukaki, H. Fujisawa, M. Tasaka [1996] Plant Physiology 110: 933-943). This indicates that gravity perception, but not the gravitropic response, occurs at 4°C. Recessive mutations were identified at three loci using this cold effect on gravitropism to screen for gravity persistence signal (gps) mutants. All three mutants had an altered response after gravistimulation at 4°C, yet had phenotypically normal responses to stimulations at RT. gps1-1 did not bend in response to the 4°C gravity stimulus upon return to RT. gps2-1 responded to the 4°C stimulus but bent in the opposite direction. gps3-1 over-responded after return to RT, continuing to bend to an angle greater than wild-type plants. At 4°C, starch-containing statoliths sedimented normally in both wild-type and the gps mutants, but auxin transport was abolished at 4°C. These results are consistent with GPS loci affecting an aspect of the gravity signal perception/transduction pathway that occurs after statolith sedimentation, but before auxin transport.Gravity is a constant stimulus governing the orientation of plant growth. In response to changes in the gravity vector, plants reorient by differential growth. When placed horizontally, shoots and roots of a plant exhibit asymmetric growth resulting in upward or downward curvature, respectively. Gravitropism is only one part of a complex response network that integrates information from developmental and environmental stimuli (Ramussen, 1995). For simplicity, the response pathway has been separated into three sequential steps: gravity perception, signal transduction, and asymmetric growth response (for review, see Sack, 1991). The first step in gravity perception is the sedimentation of amyloplasts in shoots and roots (Sack, 1991;Kiss, 2000;Weise et al., 2000).Later aspects of the gravity response are driven by the asymmetric distribution of auxin that is thought to induce the differential growth that is required for gravitropic curvature (for review, see Muday, 2001). What is much less clear are the mechanisms by which statolith sedimentation initiates the transduction of the gravitropic signal and directs the asymmetric distribution of auxin.Arabidopsis has emerged as a powerful genetic model and has been useful in the dissection of the molecular mechanisms of the gravity response (Tasaka et al., 1999;Chen et al., 2002). Arabidopsis mutants with gravitropic response defects specific to the inflorescence stem, ...

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Section: Discussionmentioning

confidence: 99%

Mutations in the Gravity Persistence Signal Loci in Arabidopsis Disrupt the Perception and/or Signal Transduction of Gravitropic Stimuli

et al. 2002

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“…It is conceivable that the degradation of specific phospholipids by phospholipases alters membrane composition and that this changes membrane structure, fluidity, or function. Although the sensing or signaling mechanism(s) involved in gravitropism remains obscure, physiological and electron microscopic analyses suggest that some membrane systems, such as endoplasmic reticulum and plasma membrane, may participate (Sack, 1997;Chen et al, 1999; Zheng and Staehelin, 2001). Thus, SGR2 may play a role in gravitropism by regulating such membrane systems.…”

Section: Sgr2 Is Similar In Sequence To Pa-pla1mentioning

confidence: 99%

SGR2, a Phospholipase-Like Protein, and ZIG/SGR4, a SNARE, Are Involved in the Shoot Gravitropism of Arabidopsis

et al. 2002

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In higher plants, the shoot and the root generally show negative and positive gravitropism, respectively. To elucidate the molecular mechanisms involved in gravitropism, we have isolated many shoot gravitropism mutants in Arabidopsis. The sgr2 and zig/sgr4 mutants exhibited abnormal gravitropism in both inflorescence stems and hypocotyls. These genes probably are involved in the early step(s) of the gravitropic response. The sgr2 mutants also had misshapen seed and seedlings, whereas the stem of the zig/sgr4 mutants elongated in a zigzag fashion. The SGR2 gene encodes a novel protein that may be part of a gene family represented by bovine phosphatidic acid-preferring phospholipase A1 containing a putative transmembrane domain. This gene family has been reported only in eukaryotes. The ZIG gene was found to encode AtVTI11, a protein that is homologous with yeast VTI1 and is involved in vesicle transport. Our observations suggest that the two genes may be involved in a vacuolar membrane system that affects shoot gravitropism. INTRODUCTIONPlants settle in their place of germination through their lifetime and cannot escape the various environmental stimuli to which they are exposed. Consequently, plants have evolved many mechanisms by which they can sense and adapt themselves to various environmental changes. Gravitropism is one of those important environmental responses, particularly for land plants. This is the response that the plant makes when it is laid flat on the ground, namely, the shoot curves up (negative gravitropism) and the root curves down (positive gravitropism). This response is necessary to position the plant so that its leaves face the source of light energy and its roots can take up water and various nutrients.A number of physiological and cytological studies using many different species of plants have demonstrated that amyloplasts that accumulate starch are involved in gravity perception as statoliths and that auxin is involved in the asymmetric growth between the upper and lower tissue of the responding organ that results in the gravitropic curvature (Sack, 1991; Kaufman et al., 1995). These studies also have suggested that various signal molecules, such as Ca 2 ϩ , calmodulin, and inositol 1,4,5-triphosphate, and pH change are involved in the signal transduction that generates the gravitropic response (Belyavskaya, 1996;Sinclair and Trewavas, 1997;Perera et al., 1999;Scott and Allen, 1999;Fasano et al., 2001).To elucidate the molecular mechanism of the gravitropic response in higher plants, many mutants with aberrant root or shoot gravitropism have been isolated from Arabidopsis (Firn et al., 2000;Tasaka et al., 2001). With respect to root or hypocotyl gravitropism, most of the mutants that are abnormal in this function also respond abnormally to auxin treatment. This suggests that a number of auxin-related genes are involved in this response. These include the AUX1 ( AUXIN RESISTANT 1 ) and EIR1/AGR1/PIN2 ( ETHYLENE INSENSITIVE ROOT 1/AGRAVITROPIC 1/PIN-FORMED 2 ) genes, which appear to be in...

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“…In early studies, these movements were first characterized by Darwin and Darwin (1880), however, description of plant movement actually dates back to the Ancient Romans (Ovid 8 AD 2008). Plants exhibit these growth-mediated responses to external cues, including water (hydrotropism, Kiss 2007), touch or contact (thigmotropism, Braam 2005), the sun or light (heliotropism and phototropism, respectively Briggs 1964;Vandenbrink et al 2014a, b;Kutschera and Briggs 2016), and gravity (gravitropism, Chen et al 1999;Kiss 2000) among others. Tropisms are important for plants, which as sessile organisms, utilize these movements to respond to external stimuli (Kaufman et al 1987;Whippo and Hangarter 2004).…”

Section: Introductionmentioning

confidence: 99%

A novel blue-light phototropic response is revealed in roots of Arabidopsis thaliana in microgravity

Vandenbrink

Herranz

Medina

et al. 2016

Planta

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Main conclusion Blue-light positive phototropism in roots is masked by gravity and revealed in conditions of microgravity. In addition, the magnitude of red-light positive phototropic curvature is correlated to the magnitude of gravity.Due to their sessile nature, plants utilize environmental cues to grow and respond to their surroundings. Two of these cues, light and gravity, play a substantial role in plant orientation and directed growth movements (tropisms). However, very little is currently known about the interaction between light-(phototropic) and gravity (gravitropic)-mediated growth responses. Utilizing the European Modular Cultivation System on board the International Space Station, we investigated the interaction between phototropic and gravitropic responses in three Arabidopsis thaliana genotypes, Landsberg wild type, as well as mutants of phytochrome A and phytochrome B. Onboard centrifuges were used to create a fractional gravity gradient ranging from reduced gravity up to 1g. A novel positive blue-light phototropic response of roots was observed during conditions of microgravity, and this response was attenuated at 0.1g. In addition, a red-light pretreatment of plants enhanced the magnitude of positive phototropic curvature of roots in response to blue illumination. In addition, a positive phototropic response of roots was observed when exposed to red light, and a decrease in response was gradual and correlated with the increase in gravity. The positive red-light phototropic curvature of hypocotyls when exposed to red light was also confirmed. Both red-light and blue-light phototropic responses were also shown to be affected by directional light intensity. To our knowledge, this is the first characterization of a positive blue-light phototropic response in Arabidopsis roots, as well as the first description of the relationship between these phototropic responses in fractional or reduced gravities.Correspondence to: John Z. Kiss. Electronic supplementary material The online version of this article

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Gravitropism in Higher Plants1

Cited by 226 publications

References 64 publications

Mutations in the Gravity Persistence Signal Loci in Arabidopsis Disrupt the Perception and/or Signal Transduction of Gravitropic Stimuli

Mutations in the Gravity Persistence Signal Loci in Arabidopsis Disrupt the Perception and/or Signal Transduction of Gravitropic Stimuli

SGR2, a Phospholipase-Like Protein, and ZIG/SGR4, a SNARE, Are Involved in the Shoot Gravitropism of Arabidopsis

A novel blue-light phototropic response is revealed in roots of Arabidopsis thaliana in microgravity

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