Reference "Microsatellites in starch-synthesizing genes in relation to starch physicochemical properties in waxy rice ( Oryza sativa L.)"

Reference ID

7736

Title

Microsatellites in starch-synthesizing genes in relation to starch physicochemical properties in waxy rice ( Oryza sativa L.)

Source

Theoretical and applied genetics, 2002, vol. 105, pp. 898-905

Authors (3)

Bao-S	Corke-H
Sun-M

Abstract

Rice starch is composed of amylose and amylopectin. Amylose content, an
important determinant of rice starch quality, is primarily controlled by the
waxy gene, encoding granule-bound starch synthase (GBSS). The starch branching
enzyme (SBE) and soluble starch synthase (SSS) play major roles in the synthesis
of amylopectin. Microsatellite polymorphisms in the three genes, the wx gene
encoding granule-bound starch synthase I, the SBE gene encoding starch branching
enzyme I and the SSS gene encoding soluble starch synthase I, were studied for
56 accessions of waxy rice ( Oryza sativa L.). Four (CT)(n) microsatellite
alleles, (CT)(16), (CT)(17), (CT)(18) and (CT)(19), at the wx locus were
detected in this set of waxy rice, of which (CT)(17) was the most frequent.
Three (CT)(n) microsatellite allele classes were found at the SBE locus, (CT)(8)
or (CT)(10) together with an insertion sequence of CTCTCGGGCGA, and (CT)(8)
alone without the insertion. There were multiple microsatellites clustered at
the SSS locus. However, these alleles can also be grouped into three classes,
i.e. the allele class SSS-A = (AC)(2) em leader TCC(TC)(11) em leader
(TC)(5)C(ACC)(11), the allele class SSS-B = (AC)(3) em leader TCT(TC)(6) em
leader (TC)(4)C(ACC)(9), and the allele class SSS-C = (AC)(3) em leader
TCT(TC)(6) em leader (TC)(4)C(ACC)(8). The analyses of starch physicochemical
properties among different microsatellite genotypes indicated that the waxy rice
group with the (CT)(19) allele, the SBE-A allele and the SSS-B allele was quite
different from other groups. Nine out of 15 accessions with a high
gelatinization temperature (GT) belonged to the wx (CT)(19) group, all of them
belonged to the SBE-A group and 13 of them belonged to the SSS-B group. These
microsatellites might be useful in marker-assisted breeding for the improvement
of rice grain quality.