The Arabidopsis SPIKE1 Gene Is Required for Normal Cell Shape Control and Tissue Development

• Published in: The Plant cell 2002-01, Vol.14 (1), p.101-118
• Main Authors: Qiu, Jin-Long, Jilk, Ross, Marks, M. David, Szymanski, Daniel B.
• Format: Article
• Language: English
• Subjects: Actins; Amino Acid Sequence; Amino acids; Arabidopsis - genetics; Arabidopsis Proteins - genetics; Arabidopsis thaliana; Cell Size - genetics; Cell Surface Extensions - genetics; Chromosome Mapping; Cloning, Molecular; Cotyledon - cytology; Cotyledon - growth & development; Cotyledons; Cytoskeleton; Cytoskeleton - genetics; Cytoskeleton - metabolism; DNA, Complementary - chemistry; DNA, Complementary - genetics; Epidermal cells; Gene Expression - genetics; Leaves; Microfilaments; Microtubules; Microtubules - metabolism; Molecular Sequence Data; Mutation; Phenotype; Phenotypes; Plant cells; Plant Epidermis - cytology; Plant Epidermis - growth & development; Plants; Seedlings; Sequence Analysis, DNA; Sequence Homology, Amino Acid; Signal Transduction - genetics; Trichomes
• ISSN: 1040-4651; 1532-298X
• DOI: 10.1105/tpc.010346

Regulated growth and cell shape control are fundamentally important to the function of plant cells, tissues, and organs. The signal transduction cascades that control localized growth and cell shape, however, are not known. To better understand the relationship between cytoskeletal organization, organelle positioning, and regulated vesicle transport, we conducted a forward genetic screen to identify genes that regulate cytoskeletal organization in plants. Because of the distinct requirements for microtubules and actin filaments during leaf trichome development, a trichome-based morphology screen is an efficient approach to identify genes that affect cytoplasmic organization. The seedling lethal spike1 mutant was identified based on trichome, cotyledon, and leaf-shape defects. The predicted SPIKE1 protein shares amino acid identity with a large family of adapter proteins present in humans, flies, and worms that integrate extracellular signals with cytoskeletal reorganization. Both the trichome phenotype and immunolocalization data suggest that SPIKE1 also is involved in cytoskeletal reorganization. The assembly of laterally clustered foci of microtubules and polarized growth are early events in cotyledon development, and both processes are misregulated in spike1 epidermal cells.