Open AccessThe structure of starch can be manipulated by changing the expression levels of starch branching enzyme IIb in rice endosperm
Author(s) -
Tanaka Naoki,
Fujita Naoko,
Nishi Aiko,
Satoh Hikaru,
Hosaka Yuko,
Ugaki Masashi,
Kawasaki Shinji,
Nakamura Yasunori
Publication year - 2004
Publication title -
plant biotechnology journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.525
H-Index - 115
eISSN - 1467-7652
pISSN - 1467-7644
DOI - 10.1111/j.1467-7652.2004.00097.x
Subject(s) - endosperm , amylopectin , starch , biology , branching (polymer chemistry) , mutant , genetically modified rice , polysaccharide , enzyme , biochemistry , glycogen branching enzyme , botany , gene , transgene , genetically modified crops , amylose , chemistry , glycogen synthase , organic chemistry
Summary When the starch branching enzyme IIb ( BEIIb ) gene was introduced into a BEIIb‐defective mutant, the resulting transgenic rice plants showed a wide range of BEIIb activity and the fine structure of their amylopectins showed considerable variation despite having the two other BE isoforms, BEI and BEIIa, in their endosperm at the same levels as in the wild‐type. The properties of the starch granules, such as their gelatinization behaviour, morphology and X‐ray diffraction pattern, also changed dramatically depending on the level of BEIIb activity, even when this was either slightly lower or higher than that of the wild‐type. The over‐expression of BEIIb resulted in the accumulation of excessive branched, water‐soluble polysaccharides instead of amylopectin. These results imply that the manipulation of BEIIb activity is an effective strategy for the generation of novel starches for use in foodstuffs and industrial applications.