Reduced expression of alpha-tubulin genes in Arabidopsis thaliana specifically affects root growth and morphology, root hair development and root gravitropism.
Different alpha-tubulin cDNA sequences fused in an antisense orientation to a CaMV 35S promoter were introduced into Arabidopsis thaliana plants. Several independent transgenic lines that showed a moderate but clear reduction of alpha-tubulin gene expression (TUA6/AS lines) were obtained and phenotypically characterized. Although no apparent abnormalities were detected in the aerial parts of TUA6/AS plants, root development was severely affected. Cells in TUA6/AS root tips were found to contain aberrant microtubular structures, to expand abnormally and to be unable to undergo regular cell division. These cellular defects caused a dramatic radial expansion of the root tip and inhibited root elongation. In addition, TUA6/AS roots displayed ectopic formation of root hairs, root hair branching and a reduced ability to respond to gravitropic challenges. Our results contribute to an improved understanding of the different roles microtubules play during root development and demonstrate that reverse genetics is a powerful tool to analyze cytoskeletal functions during plant organogenesis.
Bao
Y
Y
Laboratory of Plant Cell Biology, Institute of Molecular Agrobiology, 1 research link, National University of Singapore, 117604, Singapore.
Kost
B
B
Chua
N H
NH
D017360:Arabidopsis / Q000502:physiology*; D018506:Gene Expression Regulation, Plant; D018522:Gravitropism / Q000502:physiology*; D007700:Kinetics; D018519:Meristem / Q000502:physiology; D018517:Plant Roots / Q000166:cytology / Q000254:growth & development*; D030821:Plants, Genetically Modified / Q000502:physiology; D014404:Tubulin / Q000235:genetics*
D014404:Tubulin