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| Title: Expression profiling of genes involved in starch synthesis in sink and source organs of rice .
| | Author: Ohdan T Francisco PB Sawada T Hirose T Terao T Satoh H Nakamura Y | | Journal: J Exp . Bot . Citation: V : 56 ( 422 ) P : 3229-44 Year: 2005 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub16275672 Accession (PMID): 16275672 | | Abstract: A comprehensive analysis of the transcript levels of genes which encode starch-synthesis enzymes is fundamental for the assessment of the function of each enzyme and the regulatory mechanism for starch biosynthesis in source and sink organs .
Using quantitative real-time RT-PCR , an examination was made of the expression profiles of 27 rice genes encoding six classes of enzymes , ie ADPglucose pyrophosphorylase ( AGPase ) , starch synthase , starch branching enzyme , starch debranching enzyme , starch phosphorylase , and disproportionating enzyme in developing seeds and leaves .
The modes of gene expression were it issue and developmental stage-specific .
Four patterns of expression in the seed were identified : group 1 genes , which are expressed very early in grain formation and are presumed to be involved in the construction of fundamental cell machineries , de novo synthesis of glucan primers , and initiation of starch granules ; group 2 genes , which are highly expressed throughout endosperm development ; group 3 genes , which have transcripts that are low at the onset but which rise steeply at the start of starch synthesis in the endosperm and are thought to play essential roles in endosperm starch synthesis ; and group 4 genes , which are expressed scantly , mainly at the onset of grain development , and might be involved in synthesis of starch in the pericarp .
The methodology also revealed that the defect in the cytosolic AGPase small subunit2b ( AGPS2b ) transcription from the AGPS2 gene in endosperm sharply enhanced the expressions of endosperm and leaf plastidial AGPS1 , the endosperm cytosolic AGPase large subunit2 ( AGPL2 ) , and the leaf plastidial AGPL1 . | Matching Sentences:
[ Sen. 5, subscore: 2.00 ]: The methodology also revealed that the defect in the cytosolic AGPase small subunit2b ( AGPS2b ) transcription from the AGPS2 gene in endosperm sharply enhanced the expressions of endosperm and leaf plastidial AGPS1 , the endosperm cytosolic AGPase large subunit2 ( AGPL2 ) , and the leaf plastidial AGPL1 .
| | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
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| Title: Molecular evolution of the endosperm starch synthesis pathway genes in rice ( Oryza sativa L ) and its wild ancestor , O rufipogon L | | Author: Yu G Olsen KM Schaal BA | | Journal: Mol Biol Evol Citation: V : 28 P : 659-71 Year: 2011 Type: MEDLINE | | Literature: oryza Field: abstract Doc ID: pub20829346 Accession (PMID): 20829346 | | Abstract: The evolution of metabolic pathways is a fundamental but poorly understood aspect of evolutionary change .
One approach for understanding the complexity of pathway evolution is to examine the molecular evolution of genes that together comprise an integrated metabolic pathway .
The rice endosperm starch biosynthetic pathway is one of the most thoroughly characterized metabolic pathways in plants , and starch is a trait that has evolved in response to strong selection during rice domestication .
In this study , we have examined six key genes ( AGPL2 , AGPS2b , SSIIa , SBEIIb , GBSSI , ISA1 ) in the rice endosperm starch biosynthesis pathway to investigate the evolution of these genes before and after rice domestication .
Genome-wide sequence tagged sites data were used as a neutral reference to overcome the problems of detecting selection in species with complex demographic histories such as rice .
Five variety groups of Oryza sativa ( aus , indica , tropical japonica , temperate japonica , aromatic ) and its wild ancestor ( O rufipogon ) were sampled .
Our results showed evidence of purifying selection at AGPL2 in O rufipogon and strong evidence of positive selection at GBSSI in temperate japonica and tropical japonica varieties and at GBSSI and SBEIIb in aromatic varieties .
All the other genes showed a pattern consistent with neutral evolution in both cultivated rice and its wild ancestor .
These results indicate the important role of positive selection in the evolution of starch genes during rice domestication .
We discuss the role of SBEIIb and GBSSI in the evolution of starch quality during rice domestication and the power and limitation of detecting selection using genome-wide data as a neutral reference .
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[ Sen. 4, subscore: 1.00 ]: In this study , we have examined six key genes ( AGPL2 , AGPS2b , SSIIa , SBEIIb , GBSSI , ISA1 ) in the rice endosperm starch biosynthesis pathway to investigate the evolution of these genes before and after rice domestication .
| | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 1.00 |
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| Title: SNP in starch biosynthesis genes associated with nutritional and functional properties of rice .
| | Author: Kharabian-Masouleh A Waters DL Reinke RF Ward R Henry RJ | | Journal: Sci Rep Citation: V : 2 P : 557 Year: 2012 Type: In-Data-Review | | Literature: oryza Field: abstract Doc ID: pub22870386 Accession (PMID): 22870386 | | Abstract: Starch is a major component of human diets .
The relative contribution of variation in the genes of starch biosynthesis to the nutritional and functional properties of the rice was evaluated in a rice breeding population .
Sequencing 18 genes involved in starch synthesis in a population of 233 rice breeding lines discovered 66 functional SNPs in exonic regions .
Five genes , AGPS2b , Isoamylase1 , SPHOL , SSIIb and SSIVb showed no polymorphism .
Association analysis found 31 of the SNP were associated with differences in pasting and cooking quality properties of the rice lines .
Two genes appear to be the major loci controlling traits under human selection in rice , GBSSI ( waxy gene ) and SSIIa .
GBSSI influenced amylose content and retrogradation .
Other genes contributing to retrogradation were GPT1 , SSI , BEI and SSIIIa .
SSIIa explained much of the variation in cooking characteristics .
Other genes had relatively small effects .
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[ Sen. 4, subscore: 1.00 ]: Five genes , AGPS2b , Isoamylase1 , SPHOL , SSIIb and SSIVb showed no polymorphism .
| | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
