Deletion analysis of AGD1 reveals domains crucial for plasma membrane recruitment and function in root hair polarity.

AGD1, a plant ACAP-type ADP-ribosylation factor-GTPase activating protein (ARF-GAP), functions in specifying root hair polarity in To better understand how AGD1 modulates root hair growth, we generated full-length and domain-deleted AGD1-green fluorescent protein (GFP) constructs, and followed their localization during root hair development. AGD1-GFP localized to the cytoplasm and was recruited to specific regions of the root hair plasma membrane (PM). Distinct PM AGD1-GFP signal was first detected along the site of root hair bulge formation.

Fluorescence Imaging of the Cytoskeleton in Plant Roots.

During the past two decades the use of live cytoskeletal probes has increased dramatically due to the introduction of the green fluorescent protein. However, to make full use of these live cell reporters it is necessary to implement simple methods to maintain plant specimens in optimal growing conditions during imaging. To image the cytoskeleton in living Arabidopsis roots, we rely on a system involving coverslips coated with nutrient supplemented agar where the seeds are directly germinated.

Overlapping and divergent signaling pathways for ARK1 and AGD1 in the control of root hair polarity in Arabidopsis thaliana.

We previously showed that seedlings harboring mutations in genes encoding ARK1, an armadillo repeat-containing kinesin, or AGD1, a class 1 ARF-GAP, have root hairs that exhibit wavy/spiral growth and two tips originating from one initiation site. These root hair defects were accompanied by bundling of endoplasmic microtubules and filamentous actin (F-actin) that extended to the extreme root hair apex. The similar phenotypes of ark1 and agd1 mutants suggest a tight coordination between the cytoskeleton and membrane trafficking in the control of root hair polarity.

Divergence and Redundancy in CSLD2 and CSLD3 Function During Arabidopsis Thaliana Root Hair and Female Gametophyte Development.

The Arabidopsis cellulose synthase-like D (CSLD) 2 and 3 genes are known to function in root hair development. Here, we show that these genes also play a role in female gametophyte development because csld2 csld3 double mutants were observed to have low seed set that could be traced to defects in female transmission efficiency. Cell biological studies of csld2 csld3 ovules showed synergid cell degeneration during megagametogenesis and reduced pollen tube penetration during fertilization.

AGD1, a class 1 ARF-GAP, acts in common signaling pathways with phosphoinositide metabolism and the actin cytoskeleton in controlling Arabidopsis root hair polarity.

The Arabidopsis thaliana AGD1 gene encodes a class 1 adenosine diphosphate ribosylation factor-gtpase-activating protein (ARF-GAP). Previously, we found that agd1 mutants have root hairs that exhibit wavy growth and have two tips that originate from a single initiation point. To gain new insights into how AGD1 modulates root hair polarity we analyzed double mutants of agd1 and other loci involved in root hair development, and evaluated dynamics of various components of root hair tip growth in agd1 by live cell microscopy.

Sample preparation for fluorescence imaging of the cytoskeleton in fixed and living plant roots.

During the past decade the use of live cytoskeletal probes has increased dramatically due to the introduction of the green fluorescent protein. However, to make full use of these live cell reporters it is necessary to implement simple methods to maintain plant specimens in optimal growing conditions during imaging. To image the cytoskeleton in living Arabidopsis root cells, we rely on a system involving coverslips coated with nutrient supplemented agar where the seeds are directly germinated.

Functional analysis of the cellulose synthase-like genes CSLD1, CSLD2, and CSLD4 in tip-growing Arabidopsis cells.

A reverse genetic approach was used to investigate the functions of three members of the cellulose synthase superfamily in Arabidopsis (Arabidopsis thaliana), CELLULOSE SYNTHASE-LIKE D1 (CSLD1), CSLD2, and CSLD4. CSLD2 is required for normal root hair growth but has a different role from that previously described for CSLD3 (KOJAK). CSLD2 is required during a later stage of hair development than CSLD3, and CSLD2 mutants produce root hairs with a range of abnormalities, with many root hairs rupturing late in development.

A class I ADP-ribosylation factor GTPase-activating protein is critical for maintaining directional root hair growth in Arabidopsis.

Membrane trafficking and cytoskeletal dynamics are important cellular processes that drive tip growth in root hairs. These processes interact with a multitude of signaling pathways that allow for the efficient transfer of information to specify the direction in which tip growth occurs. Here, we show that AGD1, a class I ADP ribosylation factor GTPase-activating protein, is important for maintaining straight growth in Arabidopsis (Arabidopsis thaliana) root hairs, since mutations in the AGD1 gene resulted in wavy root hair growth.

Improved imaging of actin filaments in transgenic Arabidopsis plants expressing a green fluorescent protein fusion to the C- and N-termini of the fimbrin actin-binding domain 2.

The role of the actin cytoskeleton in plant development is intimately linked to its dynamic behavior. Therefore it is essential to continue refining methods for studying actin organization in living plant cells. The discovery of green fluorescent protein (GFP) has popularized the use of translational fusions of GFP with actin filament (F-actin) side-binding proteins to visualize in vivo actin organization in plants.

Arabidopsis EPSIN1 plays an important role in vacuolar trafficking of soluble cargo proteins in plant cells via interactions with clathrin, AP-1, VTI11, and VSR1.

Epsin and related proteins play important roles in various steps of protein trafficking in animal and yeast cells. Many epsin homologs have been identified in plant cells from analysis of genome sequences. However, their roles have not been elucidated.

Differential effects of two phospholipase D inhibitors, 1-butanol and N-acylethanolamine, on in vivo cytoskeletal organization and Arabidopsis seedling growth.

Plant development is regulated by numerous chemicals derived from a multitude of metabolic pathways. However, we know very little about the biological effects and functions of many of these metabolites in the cell. N-Acylethanolamines (NAEs) are a group of lipid mediators that play important roles in mammalian physiology.