Disease relevance of Gravity Perception

• These changes in ADH could be induced either by spaceflight hypoxia resulting from inhibition of gravity mediated O2 transport, or by a non-specific stress response due to inhibition of gravisensing [1].

High impact information on Gravity Perception

• PIN3 is expressed in gravity-sensing tissues, with PIN3 protein accumulating predominantly at the lateral cell surface [2].
• Physiological studies implicated a specific transport system that relocates auxin laterally, thereby effecting differential growth; however, neither the molecular components of this system nor the cellular mechanism of auxin redistribution on light or gravity perception have been identified [2].
• Flavonoid accumulation was found in wild-type columella cells, the site of gravity perception, and in epidermal and cortical cells, the site of differential growth, but flavonoid accumulation was absent in tt4(2YY6) roots [3].
• The cytological and molecular analysis of two mutants, shoot gravitropism 1 (sgrl), which is allelic to scarecrow (scr), and sgr7, which is allelic to short-root(shr), indicate that the endodermis is the site of gravity perception in shoots [4].
• The contribution of the extracellular matrix to gravisensing in characean cells [5].

Biological context of Gravity Perception

• The molecular mechanisms underlying gravity perception and signal transduction which control asymmetric plant growth responses are as yet unknown, but are likely to depend on the directional flux of the plant hormone auxin [6].

Anatomical context of Gravity Perception

• The actin cytoskeleton is hypothesized to play a major role in gravity perception and transduction mechanisms in roots of plants [7].
• Central root cap cells are depleted of endoplasmic microtubules and actin microfilament bundles: implications for their role as gravity-sensing statocytes [8].

Associations of Gravity Perception with chemical compounds

• Moreover, the tetrapeptide Arg-Gly-Asp-Ser (RGDS) inhibits gravisensing in a concentration-dependent manner, indicating that the gravireceptor may be an integrin-like protein [5].
• Inositol 1,4,5-trisphosphate (InsP3) has been implicated in the early signaling events of plants linking gravity sensing to the initiation of the gravitropic response [9].
• Our results show that the lateral sedimentation of chloroplasts associated with gravity sensing was prevented in cross-sections taken from the bending zone of LaCl3-treated and subsequently gravistimulated spikes and that LaCl3 completely prevented the gravity-induced, asymmetric ethylene production established across the stem-bending zone [10].
• Phase I was detected at very low concentrations (0.01 microM) of trifluoperazine and calmidazolium, did not involve growth changes, accounted for about half the total curvature of the root and may represent the specific contribution of the cap to gravity sensing [11].
• Aboard the German-Spacelab-Mission D-2 the project "Gravity Perception and Neuronal Plasticity (STATEX II)" was performed [12].

Gene context of Gravity Perception

• Furthermore, gravisensing is sensitive to protease treatment; Proteinase K, thermolysin and collagenase but not trypsin, alpha-chymotrypsin or carboxypeptidase B, inhibit gravisensing [5].
• The SCR gene was known to regulate the development of endodermis cells that are responsible for sensing gravity in a shoot [13].
• The objective of the first experiment was to determine if physical changes in gravity-mediated O2 transport can be directly measured, while the second series of experiments tested whether disruption of gravisensing can induce a non-specific ADH response [1].
• In order to study the functional roles of the root cap cells in gravity-sensing, we compared the ultrastructural organization, differentiation, and DNA content in the meristematic, elongating, and differentiating cells of root tips in Brassica rapa plants grown in space microgravity and at 1g [14].

References