Details
Original language | English |
---|---|
Pages (from-to) | 350-363 |
Number of pages | 14 |
Journal | Plant Journal |
Volume | 61 |
Issue number | 2 |
Publication status | Published - 1 Jan 2010 |
Abstract
Heterotrophic plastids of seeds perform many biosynthetic reactions. Understanding their function in crop plants is crucial for seed production. Physiological functions depend on the uptake of precursors by a range of different metabolite translocators. The 2-oxoglutarate/malate translocator gene (PsOMT), which is highly expressed during pea (Pisum sativum) embryo maturation, has an important role during seed storage. PsOMT functions have been studied by antisense repression in maturing pea embryos, and were found to reduce mRNA levels and transport rates of 2-oxoglutarate and malate by 50-70%. Combined metabolite and transcript profiling revealed that OMT repression affects the conversion of carbohydrates from sucrose into amino acids and proteins, decreases seed weight and delays maturation. OMT-repressed pea embryos have increased levels of organic acids, ammonia, and higher ratios of Asn : Asp and Gln : Glu. Decreased levels of most other amino acids indicate the reduced usage of organic acids and ammonia for amino acid biosynthesis in plastids, possibly caused by substrate limitation of the plastidial glutamine synthetase/glutamine- 2-oxoglutarate aminotransferase cycle. Expression of storage proteins is delayed, and mature seeds have reduced protein content. Downregulated gene expression of starch biosynthesis and plastidial glucose-6-phosphate transport in asOMT embryos reveals that decreased 2-oxoglutarate/malate transport capacity affects other pathways of central carbon metabolism. Gene expression analysis related to plastid physiology revealed that OMT repression delays differentiation of storage plastids, thereby maintaining gene expression associated with green chloroplasts. We conclude that OMT is important for protein-storing crop seeds, and is necessary for amino acid biosynthesis in pea seeds. In addition, carbon supply as mediated by OMT controls plastid differentiation during seed maturation.
Keywords
- 2-oxoglutarate/malate translocator, Amino acid metabolism, Legume seed maturation, Metabolic regulation, Plastids, Storage proteins
ASJC Scopus subject areas
- Biochemistry, Genetics and Molecular Biology(all)
- Genetics
- Agricultural and Biological Sciences(all)
- Plant Science
- Biochemistry, Genetics and Molecular Biology(all)
- Cell Biology
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In: Plant Journal, Vol. 61, No. 2, 01.01.2010, p. 350-363.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - The 2-oxoglutarate/malate translocator mediates amino acid and storage protein biosynthesis in pea embryos
AU - Riebeseel, Erik
AU - Häusler, Rainer E.
AU - Radchuk, Ruslana
AU - Meitzel, Tobias
AU - Hajirezaei, Mohammad Reza
AU - Emery, R. J.Neil
AU - Küster, Helge
AU - Nunes-Nesi, Adriano
AU - Fernie, Alisdair R.
AU - Weschke, Winfriede
AU - Weber, Hans
PY - 2010/1/1
Y1 - 2010/1/1
N2 - Heterotrophic plastids of seeds perform many biosynthetic reactions. Understanding their function in crop plants is crucial for seed production. Physiological functions depend on the uptake of precursors by a range of different metabolite translocators. The 2-oxoglutarate/malate translocator gene (PsOMT), which is highly expressed during pea (Pisum sativum) embryo maturation, has an important role during seed storage. PsOMT functions have been studied by antisense repression in maturing pea embryos, and were found to reduce mRNA levels and transport rates of 2-oxoglutarate and malate by 50-70%. Combined metabolite and transcript profiling revealed that OMT repression affects the conversion of carbohydrates from sucrose into amino acids and proteins, decreases seed weight and delays maturation. OMT-repressed pea embryos have increased levels of organic acids, ammonia, and higher ratios of Asn : Asp and Gln : Glu. Decreased levels of most other amino acids indicate the reduced usage of organic acids and ammonia for amino acid biosynthesis in plastids, possibly caused by substrate limitation of the plastidial glutamine synthetase/glutamine- 2-oxoglutarate aminotransferase cycle. Expression of storage proteins is delayed, and mature seeds have reduced protein content. Downregulated gene expression of starch biosynthesis and plastidial glucose-6-phosphate transport in asOMT embryos reveals that decreased 2-oxoglutarate/malate transport capacity affects other pathways of central carbon metabolism. Gene expression analysis related to plastid physiology revealed that OMT repression delays differentiation of storage plastids, thereby maintaining gene expression associated with green chloroplasts. We conclude that OMT is important for protein-storing crop seeds, and is necessary for amino acid biosynthesis in pea seeds. In addition, carbon supply as mediated by OMT controls plastid differentiation during seed maturation.
AB - Heterotrophic plastids of seeds perform many biosynthetic reactions. Understanding their function in crop plants is crucial for seed production. Physiological functions depend on the uptake of precursors by a range of different metabolite translocators. The 2-oxoglutarate/malate translocator gene (PsOMT), which is highly expressed during pea (Pisum sativum) embryo maturation, has an important role during seed storage. PsOMT functions have been studied by antisense repression in maturing pea embryos, and were found to reduce mRNA levels and transport rates of 2-oxoglutarate and malate by 50-70%. Combined metabolite and transcript profiling revealed that OMT repression affects the conversion of carbohydrates from sucrose into amino acids and proteins, decreases seed weight and delays maturation. OMT-repressed pea embryos have increased levels of organic acids, ammonia, and higher ratios of Asn : Asp and Gln : Glu. Decreased levels of most other amino acids indicate the reduced usage of organic acids and ammonia for amino acid biosynthesis in plastids, possibly caused by substrate limitation of the plastidial glutamine synthetase/glutamine- 2-oxoglutarate aminotransferase cycle. Expression of storage proteins is delayed, and mature seeds have reduced protein content. Downregulated gene expression of starch biosynthesis and plastidial glucose-6-phosphate transport in asOMT embryos reveals that decreased 2-oxoglutarate/malate transport capacity affects other pathways of central carbon metabolism. Gene expression analysis related to plastid physiology revealed that OMT repression delays differentiation of storage plastids, thereby maintaining gene expression associated with green chloroplasts. We conclude that OMT is important for protein-storing crop seeds, and is necessary for amino acid biosynthesis in pea seeds. In addition, carbon supply as mediated by OMT controls plastid differentiation during seed maturation.
KW - 2-oxoglutarate/malate translocator
KW - Amino acid metabolism
KW - Legume seed maturation
KW - Metabolic regulation
KW - Plastids
KW - Storage proteins
UR - http://www.scopus.com/inward/record.url?scp=73849086464&partnerID=8YFLogxK
U2 - 10.1111/j.1365-313X.2009.04058.x
DO - 10.1111/j.1365-313X.2009.04058.x
M3 - Article
C2 - 19845879
AN - SCOPUS:73849086464
VL - 61
SP - 350
EP - 363
JO - Plant Journal
JF - Plant Journal
SN - 0960-7412
IS - 2
ER -