Mechano-sensitive orientation of cortical microtubules during gravitropism in azuki bean epicotyls

Ikushima, Toshimitsu; Shimmen, Teruo

doi:10.1007/s10265-004-0189-8

Cited by 26 publications

(22 citation statements)

References 34 publications

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“…‘Pinot Noir’ was observed, which was already manifest at the lowest concentration (20 μM) tested. This Gd 3+ sensitivity is only slightly lower than the values found from patch–clamp measurements in onion scale epidermis (Ding and Pickard, 1993) and much higher than that reported for other plant tissues, such as adzuki bean hypocotyl (Ikushima and Shimmen, 2005). Interestingly, the alkalinization response in V. rupestris was much more reistant to Gd 3+ inhibition.…”

Section: Discussioncontrasting

confidence: 63%

The cytoskeleton enhances gene expression in the response to the Harpin elicitor in grapevine

Qiao

Chang

Nick

2010

Journal of Experimental Botany

113

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The cytoskeleton undergoes dramatic reorganization during plant defence. This response is generally interpreted as part of the cellular repolarization establishing physical barriers against the invading pathogen. To gain insight into the functional significance of cytoskeletal responses for defence, two Vitis cell cultures that differ in their microtubular dynamics were used, and the cytoskeletal response to the elicitor Harpin in parallel to alkalinization of the medium as a fast response, and the activation of defence-related genes were followed. In one cell line derived from the grapevine cultivar ‘Pinot Noir’, microtubules contained mostly tyrosinylated α-tubulin, indicating high microtubular turnover, whereas in another cell line derived from the wild grapevine V. rupestris, the α-tubulin was strongly detyrosinated, indicating low microtubular turnover. The cortical microtubules were disrupted and actin filaments were bundled in both cell lines, but the responses were elevated in V. rupestris as compared with V. vinifera cv. ‘Pinot Noir’. The cytoskeletal responsiveness correlated with elicitor-induced alkalinization and the expression of defence genes. Using resveratrol synthase and stilbene synthase as examples, it could be shown that pharmacological manipulation of microtubules could induce gene expression in the absence of elicitor. These findings are discussed with respect to a role for microtubules as positive regulators of defence-induced gene expression.

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Section: Discussioncontrasting

confidence: 63%

The cytoskeleton enhances gene expression in the response to the Harpin elicitor in grapevine

Qiao

Chang

Nick

2010

Journal of Experimental Botany

113

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“…The study of molecular sensing mechanisms (2,15) can thus now be extended to the cross-talk between gravi-and propriosensing as a function of organ size. Candidate mechanisms for the proprioception of the curvature may involve mechanical strain-or stress-sensing (27,30) triggering microtubules reorientation (28,29). Ethylene seems to be involved (17) but not the lateral transport of auxin (21).…”

mentioning

confidence: 99%

Unifying model of shoot gravitropism reveals proprioception as a central feature of posture control in plants

Bastien

Bohr

Moulia

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

152

315

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Gravitropism, the slow reorientation of plant growth in response to gravity, is a key determinant of the form and posture of land plants. Shoot gravitropism is triggered when statocysts sense the local angle of the growing organ relative to the gravitational field. Lateral transport of the hormone auxin to the lower side is then enhanced, resulting in differential gene expression and cell elongation causing the organ to bend. However, little is known about the dynamics, regulation, and diversity of the entire bending and straightening process. Here, we modeled the bending and straightening of a rod-like organ and compared it with the gravitropism kinematics of different organs from 11 angiosperms. We show that gravitropic straightening shares common traits across species, organs, and orders of magnitude. The minimal dynamic model accounting for these traits is not the widely cited gravisensing law but one that also takes into account the sensing of local curvature, what we describe here as a graviproprioceptive law. In our model, the entire dynamics of the bending/straightening response is described by a single dimensionless "bending number" B that reflects the ratio between graviceptive and proprioceptive sensitivities. The parameter B defines both the final shape of the organ at equilibrium and the timing of curving and straightening. B can be estimated from simple experiments, and the model can then explain most of the diversity observed in experiments. Proprioceptive sensing is thus as important as gravisensing in gravitropic control, and the B ratio can be measured as phenotype in genetic studies.perception | signaling | movement | morphogenesis

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“…For instance, Ikushima and Shimmen (2005) have recently shown in azuki bean epicotyls that the reorientation of cortical microtubules is controlled by curvature and not by gravity signals. The degree of contribution of microtubule reorientation to tropistic curvatures may be variable, according to species, organs, and culture conditions.…”

Section: Discussionmentioning

confidence: 98%

“…In contrast, it has been proposed that microtubule reorientation occurs as the result of tropistic curvature and is not the cause of the curvature (Fischer and Schopfer 1998). Recent analysis with azuki bean epicotyls also suggested that the reorientation of cortical microtubules was controlled by curvature and not by gravity signal (Ikushima and Shimmen 2005). However, in maize coleoptiles, microtubules do not reorient passively after curvature, but reorient actively in response to gravitropic stimulation (Himmelspach and Nick 2001).…”

Section: Introductionmentioning

confidence: 92%

Cellular basis for the automorphic curvature of rice coleoptiles on a three-dimensional clinostat: possible involvement of reorientation of cortical microtubules

et al. 2005

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Coleoptiles of rice (Oryza sativa L.) show a spontaneous (automorphic) curvature toward the caryopsis under microgravity conditions. The possible involvement of the reorientation of cortical microtubules in automorphic curvature was studied in rice coleoptiles grown on a three-dimensional clinostat. When rice seedlings that had been grown in the normal gravitational field were transferred to the clinostat in the dark, cortical microtubules of epidermal cells in the dorsal side of the coleoptiles oriented more transversely than the ventral side within 0.5 h. The rotation on the clinostat also increased the cell wall extensibility in the dorsal side and decreased the extensibility in the ventral side, and induced automorphic curvature. The reorientation of cortical microtubules preceded the changes in the cell wall extensibility and the curvature. The irradiation of rice seedlings with white light from above inhibited microtubule reorientation and changes in the cell wall extensibility, as well as curvature of coleoptiles. Also, colchicine, applied to the bending region of coleoptiles, partially inhibited the automorphic curvature. These results suggest that reorientation of cortical microtubules is involved in causing automorphic curvature in rice coleoptiles on the clinostat.

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Mechano-sensitive orientation of cortical microtubules during gravitropism in azuki bean epicotyls

Cited by 26 publications

References 34 publications

The cytoskeleton enhances gene expression in the response to the Harpin elicitor in grapevine

The cytoskeleton enhances gene expression in the response to the Harpin elicitor in grapevine

Unifying model of shoot gravitropism reveals proprioception as a central feature of posture control in plants

Cellular basis for the automorphic curvature of rice coleoptiles on a three-dimensional clinostat: possible involvement of reorientation of cortical microtubules

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