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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
7
pubmed:dateCreated
2007-7-10
pubmed:abstractText
To elucidate the role of SSIIIa during starch synthesis in rice (Oryza sativa L.) endosperm, we characterized null mutants of this gene, generated by T-DNA insertions. Scanning electron microscope (SEM) analysis revealed that the starch granules in these mutants are smaller and rounder compared with the wild type controls, and that the mutant endosperm is characterized by a loosely packed central portion exhibiting a floury-like phenotype. Hence, the OsSSIIIa (Oryza sativa SSIIIa) mutations are referred to as white-core floury endosperm 5-1 (flo5-1) and flo5-2. Based upon their X-ray diffraction patterns, the crystallinity of the starch in the flo5 mutant endosperm is decreased compared with wild type. Through determination of the chain-length distribution of the mutant endosperm starch, we found that flo5-1 and flo5-2 mutants have reduced the content of long chains with degree of polymerization (DP) 30 or greater compared with the controls. This suggests that OsSSIIIa/Flo5 plays an important role in generating relatively long chains in rice endosperm. In addition, DP 6 to 8 and DP 16 to 20 appeared to be reduced in endosperm starch of flo5-1 and flo5-2, whereas DP 9 to 15 and DP 22 to 29 were increased in these mutants. By the use of differential scanning calorimetry (DSC), the gelatinization temperatures of endosperm starch were found to be 1-5 degrees C lower than those of the control. We propose a distinct role for OsSSIIIa/Flo5 and the coordinated action of other SS isoforms during starch synthesis in the seed endosperm of rice.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0721-7714
pubmed:author
pubmed:issnType
Print
pubmed:volume
26
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1083-95
pubmed:meshHeading
pubmed:year
2007
pubmed:articleTitle
Knockout of a starch synthase gene OsSSIIIa/Flo5 causes white-core floury endosperm in rice (Oryza sativa L.).
pubmed:affiliation
Plant Metabolism Research Center and Graduate School of Biotechnology, Kyung Hee University, Yongin 446-701, Korea. ryoo1009@khu.ac.kr
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't