A member of the maize isopentenyl transferase gene family, Zea mays isopentenyl transferase 2 (ZmIPT2), encodes a cytokinin biosynthetic enzyme expressed during kernel development
| Autor: | Jeffrey E. Habben, Norbert Brugière, Nancy Rizzo, Sabrina Humbert, Jennifer Bohn |
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| Rok vydání: | 2008 |
| Předmět: |
Cytokinins
Apical dominance Molecular Sequence Data Restriction Mapping Arabidopsis Plant Science Biology Polymerase Chain Reaction Zea mays Endosperm chemistry.chemical_compound Genetics Amino Acid Sequence Plastid Gene Conserved Sequence Phylogeny Plant Proteins Alkyl and Aryl Transferases Binding Sites Arabidopsis Proteins fungi Gene Amplification food and beverages Transfer cell General Medicine Transferase Gene Plant Leaves Biochemistry chemistry Multigene Family Cytokinin Ectopic expression Agronomy and Crop Science |
| Zdroj: | Plant Molecular Biology. 67:215-229 |
| ISSN: | 1573-5028 0167-4412 |
| Popis: | Cytokinins (CKs) are plant hormones that regulate a large number of processes associated with plant growth and development such as induction of stomata opening, delayed senescence, suppression of auxin-induced apical dominance, signaling of nitrogen availability, differentiation of plastids and control of sink strength. In maize, CKs are thought to play an important role in establishing seed size and increasing seed set under normal and unfavorable environmental conditions therefore influencing yield. In recent years, the discovery of isopentenyl transferase (IPT) genes in plants has shed light on the CK biosynthesis pathway in plants. In an effort to increase our understanding of the role played by CKs in maize development and sink-strength, we identified several putative IPT genes using a bioinformatics approach. We focused our attention on one gene in particular, ZmIPT2, because of its strong expression in developing kernels. The expression of the gene and its product overlays the change in CK levels in developing kernels suggesting a major role in CK biosynthesis for kernel development. We demonstrate that at 8-10 days after pollination (DAP) the endosperm and especially the basal transfer cell layer (BETL) is a major site of ZmIPT2 expression, and that this expression persists in the BETL and the developing embryo into later kernel development stages. We show that ectopic expression of ZmIPT2 in calli and in planta created phenotypes consistent with CK overproduction. We also show that ZmIPT2 preferentially uses ADP and ATP over AMP as the substrates for dimethylallyl diphosphate (DMAPP) IPT activity. The expression pattern of ZmIPT2 in the BETL, endosperm and embryo during kernel development will be discussed with an emphasis on the suggested role of CKs in determining sink-strength and grain production in crop plants. |
| Databáze: | OpenAIRE |
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