Defects in CTP:PHOSPHORYLETHANOLAMINE CYTIDYLYLTRANSFERASE affect embryonic and postembryonic development in Arabidopsis.
A TILLING strategy (for targeting-induced local-scale lesions in genomes) was used in Arabidopsis thaliana to isolate mutants of a gene encoding CTP:PHOSPHORYLETHANOLAMINE CYTIDYLYLTRANSFERASE (PECT; EC 2.7.7.14), a rate-limiting enzyme in phosphatidylethanolamine biosynthesis. A null mutation, pect1-6, caused embryo abortion before the octant stage. However, reciprocal crosses revealed that pect1-6 caused no significant gametophytic defect. In pect1-4, PECT activity was decreased by 74%. Growth was generally normal in these mutants, despite delays in embryo maturation and reduced fertility. At low temperatures, however, homozygotic pect1-4 plants displayed dwarfism. PECT activity was decreased by 47% in heterozygotic pect1-6 plants and by 80% in pect1-4/pect1-6 F1 plants, which also displayed a small but significant decrease of phosphatidylethanolamine and a reciprocal increase in phosphatidylcholine. These lipid changes were fully reversed by wild-type PECT1 expression. pect1-4/pect1-6 F1 plants displayed severe dwarfism, tissue abnormalities, and low fertility, which was attributable in part to inhibition of anther, embryo, and ovule development, as was the reduced fertility of pect1-4 seedlings. PECT1 cDNA expression under the control of an inducible promoter partially rectified the mutant phenotypes observed in pect1-4/pect1-6 F1 seedlings, indicating that malfunctions in different tissues have a synergistic effect on the mutant phenotypes.
Mizoi
Junya
J
Department of Biological Sciences, Graduate School of Science, University of Tokyo, Tokyo 113-0033, Japan.
Nakamura
Masanobu
M
Nishida
Ikuo
I
D000483:Alleles; D017360:Arabidopsis / Q000196:embryology* / Q000201:enzymology* / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D001426:Bacterial Proteins / Q000378:metabolism; D035264:Flowers / Q000166:cytology / Q000201:enzymology; D020869:Gene Expression Profiling; D006720:Homozygote; D050356:Lipid Metabolism; D008164:Luminescent Proteins / Q000378:metabolism; D050505:Mutant Proteins / Q000302:isolation & purification; D009154:Mutation / Q000235:genetics; D009713:Nucleotidyltransferases / Q000235:genetics* / Q000378:metabolism*; D010641:Phenotype; D018515:Plant Leaves / Q000166:cytology / Q000201:enzymology; D018517:Plant Roots / Q000166:cytology / Q000201:enzymology; D018520:Plant Shoots / Q000166:cytology / Q000201:enzymology; D030821:Plants, Genetically Modified; D021381:Protein Transport; D012316:RNA Nucleotidyltransferases / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D012639:Seeds / Q000166:cytology / Q000201:enzymology; D013696:Temperature; D019076:Transgenes
D029681:Arabidopsis Proteins; D001426:Bacterial Proteins; D008164:Luminescent Proteins; D050505:Mutant Proteins; C054562:yellow fluorescent protein, Bacteria; D009713:Nucleotidyltransferases; D012316:RNA Nucleotidyltransferases; C020126:Ethanolamine-phosphate cytidylyltransferase; C518492:Pect1 protein, Arabidopsis