Abstract
Plant cells surrounded with rigid cell walls cannot move during development. Cell morphogenesis, which partly depends on directional cell elongation, plays an important role for polarized organ development. In plant, cortical microtubules, aligned at the cell cortex, are known to have an important role in the regulation of directional cell growth. To understand the mechanism that regulates the directional cell elongation, we isolated itosugi (itg) mutant of Arabidopsis, which shows defects in elongation of several organs, including stems, hypocotyls and roots. Cytological analyses of itg mutants revealed that longitudinal cell elongation was suppressed and that radial cell expansion was promoted in hypocotyls and roots. ITG-GFP was found in dot-like structures at the cell cortex, and co-localized with cortical microtubules. These results suggest that ITG may regulate anisotropic cell growth by way of its association with cortical microtubule.
