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The cytoskeleton and gravitropism in higher plantsThe cellular and molecular mechanisms underlying the gravitropic response of plants have continued to elude plant biologists despite more than a century of research. Lately there has been increased attention on the role of the cytoskeleton in plant gravitropism, but several controversies and major gaps in our understanding of cytoskeletal involvement in gravitropism remain. A major question in the study of plant gravitropism is how the cytoskeleton mediates early sensing and signal transduction events in plants. Much has been made of the actin cytoskeleton as the cellular structure that sedimenting amyloplasts impinge upon to trigger the downstream signaling events leading to the bending response. There is also strong molecular and biochemical evidence that the transport of auxin, an important player in gravitropism, is regulated by actin. Organizational changes in microtubules during the growth response phase of gravitropism have also been well documented, but the significance of such reorientations in controlling differential cellular growth is unclear. Studies employing pharmacological approaches to dissect cytoskeletal involvement in gravitropism have led to conflicting results and therefore need to be interpreted with caution. Despite the current controversies, the revolutionary advances in molecular, biochemical, and cell biological techniques have opened up several possibilities for further research into this difficult area. The myriad proteins associated with the plant cytoskeleton that are being rapidly characterized provide a rich assortment of candidate regulators that could be targets of the gravity signal transduction chain. Cytoskeletal and ion imaging in real time combined with mutant analysis promises to provide a fresh start into this controversial area of research.
Document ID
20040088311
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Blancaflor, Elison B. (The Samuel Roberts Noble Foundation Inc. Ardmore, Oklahoma 73401, United States)
Date Acquired
August 21, 2013
Publication Date
June 1, 2002
Publication Information
Publication: Journal of plant growth regulation
Volume: 21
Issue: 2
ISSN: 0721-7595
Subject Category
Life Sciences (General)
Funding Number(s)
CONTRACT_GRANT: NAG2-1518
Distribution Limits
Public
Copyright
Other
Keywords
Review
NASA Discipline Plant Biology
Review, Tutorial
Non-NASA Center