15th International Conference on Arabidopsis Research - TAIR

T02-065
Role of CHAYOTE in root hair development and
epidermal cell patterning
Olga Ortega-Martínez(1), Paul Linstead(1), Rachel Carol(1), Liam Dolan(1)
1-John Innes Centre, Norwich, NR4 7UH, UK
The Brassicaceae root epidermis has been used as a simple model to understand
how cells become specified in multicellular organisms. The Arabidopsis
root epidermis has two kinds of cells: trichoblasts, located over the intercellular
space between two underlying cortical cells and atrichoblasts located over
a single cortical cell (Dolan et al., 1993). Root hairs are cylindrical outgrowths
from trichoblasts and exhibit a form of polarised growth called tip growth.
We isolated chayote (cht) from a EMS mutagenised population in a screen for
root hair defective plants. cht root-hairs are longer than wild-type and have
a wavy appearance, implicating CHT in root hair elongation and morphogenesis.
In addition, hair density is higher in cht roots and suggests that CHT
plays a role in epidermal cell patterning. More detailed phenotypic analysis
identified an alteration in the quiescent centre (QC; slowly-dividing cells controlling
root meristem organisation). CHT mutants display a higher frequency
of division in these cells leading to disorganisation of cells in the meristem
after several days.
Dolan, L., K. Janmaat, et al. (1993). “Cellular organisation of the Arabidopsis thaliana
root.”Development 119(1): 71-84
15 th <strong>International</strong> <strong>Conference</strong> on Arabidopsis Research 2004 · Berlin
T02-066
GONZO1 regulates leaf polarity in Arabidopsis
Michael R. Smith(1), Scott Poethig(1)
1-University of Pennsylvania
Lateral organs arise from the shoot and floral apical meristem and exhibit an
adaxial/abaxial polarity. E2023 is an enhancer trap line that expresses GFP
preferentially in the abaxial tissue of the hypocotyl and stem. The enhancer
trap is inserted in the promoter of a transferase (GONZO1) and results in a
reduction in the expression of this gene. Plants homozygous for the E2023
insertion and kan1 resemble kan1kan2 mutants. Our results indicate that
GONZO1 promotes abaxial identity, perhaps by directly or indirectly regulating
members of the KANADI gene family.
T02 Development 2 (Shoot, Root)