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Re-programming of gene expression in the CS8 rice line over-expressing ADPglucose pyrophosphorylase induces a suppressor of starch biosynthesis.
- Source :
-
The Plant journal : for cell and molecular biology [Plant J] 2019 Mar; Vol. 97 (6), pp. 1073-1088. Date of Electronic Publication: 2019 Jan 14. - Publication Year :
- 2019
-
Abstract
- The CS8 transgenic rice (Oryza sativa L.) lines expressing an up-regulated glgC gene produced higher levels of ADPglucose (ADPglc), the substrate for starch synthases. However, the increase in grain weight was much less than the increase in ADPglc levels suggesting one or more downstream rate-limiting steps. Endosperm starch levels were not further enhanced in double transgenic plants expressing both glgC and the maize brittle-1 gene, the latter responsible for transport of ADPglc into the amyloplast. These studies demonstrate that critical processes within the amyloplast stroma restrict maximum carbon flow into starch. RNA-seq analysis showed extensive re-programming of gene expression in the CS8 with 2073 genes up-regulated and 140 down-regulated. One conspicuous gene, up-regulated ~15-fold, coded for a biochemically uncharacterized starch binding domain-containing protein (SBDCP1) possessing a plastid transit peptide. Confocal microscopy and transmission electron microscopy analysis confirmed that SBDCP1 was located in the amyloplasts. Reciprocal immunoprecipitation and pull-down assays indicated an interaction between SBDCP1 and starch synthase IIIa (SSIIIa), which was down-regulated at the protein level in the CS8 line. Furthermore, binding by SBDCP1 inhibited SSIIIa starch polymerization activity in a non-competitive manner. Surprisingly, artificial microRNA gene suppression of SBDCP1 restored protein expression levels of SSIIIa in the CS8 line resulting in starch with lower amylose content and increased amylopectin chains with a higher degree of polymerization. Collectively, our results support the involvement of additional non-enzymatic factors such as SBDCP in starch biosynthesis.<br /> (© 2018 The Authors The Plant Journal © 2018 John Wiley & Sons Ltd.)
- Subjects :
- Down-Regulation
Endosperm metabolism
Gene Expression
Gene Expression Profiling
Glucose-1-Phosphate Adenylyltransferase genetics
Glucose-1-Phosphate Adenylyltransferase metabolism
Oryza genetics
Oryza physiology
Plant Proteins genetics
Plants, Genetically Modified
Plastids metabolism
Starch Synthase genetics
Starch Synthase metabolism
Up-Regulation
Carbohydrate Metabolism
Oryza enzymology
Plant Proteins metabolism
Starch biosynthesis
Zea mays genetics
Subjects
Details
- Language :
- English
- ISSN :
- 1365-313X
- Volume :
- 97
- Issue :
- 6
- Database :
- MEDLINE
- Journal :
- The Plant journal : for cell and molecular biology
- Publication Type :
- Academic Journal
- Accession number :
- 30523657
- Full Text :
- https://doi.org/10.1111/tpj.14180