Open AccessThe GURKE Gene Encoding an Acetyl-CoA Carboxylase is Required for Partitioning the Embryo Apex into Three Subregions in Arabidopsis
Author(s) -
Takahito Kajiwara,
Masahiko Furutani,
Ken-ichiro Hibara,
Masao Tasaka
Publication year - 2004
Publication title -
plant and cell physiology/plant and cell physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.975
H-Index - 152
eISSN - 1471-9053
pISSN - 0032-0781
DOI - 10.1093/pcp/pch148
Subject(s) - cotyledon , arabidopsis , mutant , embryo , meristem , biology , apex (geometry) , gene , pyruvate carboxylase , genetics , microbiology and biotechnology , biochemistry , botany , enzyme
In Arabidopsis, three major regions, which ultimately develop into the two cotyledons, the cotyledon boundaries and the shoot apical meristem (SAM), are formed at the apex of the globular stage embryo. To reveal the molecular mechanism underlying this pattern formation, we isolated a cotyledon-defective mutant from EMS mutagenized lines. This mutant completely lacks cotyledons in the most severe cases, and is allelic to gurke (gk), which was previously reported as a mutant defective in apical patterning of the embryo. To evaluate the morphological effects of the mutation in the GK gene, we investigated the expression patterns in gk embryos of SHOOT MERISTEMLESS (STM), AINTEGUMENTA (ANT) and CUP-SHAPED COTYLEDON1 (CUC1), which are markers of the SAM, cotyledons and cotyledon boundaries, respectively. Expression of all these genes largely overlapped in gk, suggesting a failure to partition the apex of the embryo into the three subregions. Enlargement of the CUC1 expression domain was also observed and may explain the inhibition of cotyledon development in gk. Moreover, we cloned the GK gene, and confirmed that it encodes ACC1, an acetyl-CoA carboxylase which catalyzes malonyl-CoA synthesis. Our results suggest that metabolites derived from malonyl-CoA are required for partitioning of the apical part of the embryo.