cot1: A regulator of Arabidopsis trichome initiation

Daniel B. Szymanski, University of Minnesota Twin Cities
Daniel A. Klis, University of Minnesota Twin Cities
John C. Larkin, University of Minnesota Twin Cities
M. David Marks, University of Minnesota Twin Cities

Abstract

In Arabidopsis, the timing and spatial arrangement of trichome initiation is tightly regulated and requires the activity of the GLABROUSI (GL1) gene. The COTYLEDON TRICHOME 1 (COT1) gene affects trichome initiation during late stages of leaf development and is described in this article. In the wild-type background, cot1 has no observable effect on trichome initiation. GL1 overexpression in wild-type plants leads to a modest number of ectopic trichomes and to a decrease in trichome number on the adaxial leaf surface. The cot1 mutation enhances GL1-overexpression-dependent ectopic trichome formation and also induces increased leaf trichome initiation. The expressivity of the cot1 phenotype is sensitive to cot1 and 35S: GL1 gene dosage, and the most severe phenotypes are observed when cot1 and 35S:GL1 are homozygous. The COT1 locus is located on chromosome 2 15.3 cM north of er. Analysis of the interaction between cot1, lry, and 35S:GL1 suggests that COT1 is part of a complex signal transduction pathway that regulates GL1-dependent adoption of the trichome cell fate.