The GLOBULAR ARREST1 gene, which is involved in the biosynthesis of folates, is essential for embryogenesis in Arabidopsis thaliana.
We identified a mutation in Arabidopsis that resulted in defective embryos, and we designated this mutation globular arrest1 (gla1). The predicted amino acid sequence encoded by the GLA1 gene is homologous to the amino acid sequences of folylpolyglutamate synthetase (FPGS) and dihydrofolate synthetase (DHFS), which participate in folate biosynthesis. The defect of gla1 in the formation of calli was rescued by the supplement of 5-formyl tetrahydrofolate. These results indicated that GLA1 is involved in the biosynthesis of tetrahydrofolate. The gla1 embryos developed normally in the early stage of development but did not undergo the transition to the heart stage. Thus, the function of the GLA1 gene in embryogenesis appears to be required after the globular stage. However, when the levels of GLA1 transcripts in transgenic plants were increased by introduction of several copies of a GLA1 transgene (GLA6.8), the gla1 embryos that grew on gla1/gla1 GLA6.8/- plants developed as far as the heart to bent-cotyledon stage. This result suggests that the GLA1 function is provided to embryos by maternal tissues until embryos reach the globular stage.
Ishikawa
Takaaki
T
Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan.
Machida
Chiyoko
C
Yoshioka
Yasushi
Y
Kitano
Hidemi
H
Machida
Yasunori
Y
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000187:drug effects / Q000196:embryology* / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D005492:Folic Acid / Q000096:biosynthesis*; D018506:Gene Expression Regulation, Plant; D005816:Genetic Complementation Test; D005838:Genotype; D002955:Leucovorin / Q000096:biosynthesis / Q000494:pharmacology; D008969:Molecular Sequence Data; D015394:Molecular Structure; D009154:Mutation / Q000235:genetics; D010641:Phenotype; D030821:Plants, Genetically Modified; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012639:Seeds / Q000187:drug effects / Q000196:embryology / Q000235:genetics; D017422:Sequence Analysis, DNA; D019076:Transgenes / Q000235:genetics
D029681:Arabidopsis Proteins; C480842:GLA1 protein, Arabidopsis; D012333:RNA, Messenger; D005492:Folic Acid; D002955:Leucovorin