Model Cell: Trichome
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Unicellular epidermal trichomes of Arabiopsis are 300-500 µm tall and distributed in a non-random pattern on the leaf surface. Arabidopsis leaves display both unbranched and 3-5 branched trichomes but stem trichomes are usually unbranched. Trichomes initiate as epidermal bumps, and grow into a cylinderical form that may develop distinct branch sites. Branch initiation is followed by rapid cell expansion to give the stellate form. Mature Arabidopsis trichomes develop a papillate surface.
Wild Type Arabidopsis Trichome [left]
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Developing trichomes of Arabidopsis respond rapidly to alterations in microtubule dynamics. Both stabilization (using drugs like taxol), or destabilization (using chemicals like oryzalin) of microtubules results in isotropic cell expansion to produce swollen trichomes. Trichome branch initiation clearly involves microtubules as transient stabilization of microtubules allows branch initiation in unbranched trichomes.
Some of the genes involved in trichome cell morphogenesis have been identified.
Microtubule Compromised Trichomes [right]
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Trichome morphology is greatly altered by changes in the actin cytoskeleton. Actin-inhibitor treatments affect trichome cell expansion and produce randomly distorted trichomes.
An actin compromised Trichome. [left]
Our lab works on the molecular and cell biological aspects of actin-microtubule interactions during cell shape development using Arabidopsis trichomes as a model cell type. Recently several genes involved in actin-dependant trichome cell morphogenesis have been identified
