Biochemical analysis of new type mutants of japonica rice that accumulate water-soluble α-glucans in the endosperm but retain full starch debranching enzyme activities

Tsuyoshi Nakagami, Hiroki Yoshihara, Tetsuhiro Nakamura, Yoshinori Utsumi, Takayuki Sawada, Naoko Fujita, Hikaru Satoh, Yasunori Nakamura

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

Amylopectin has a highly regulated branched structure called cluster structure, which causes the glucan to be hydrophobic and to form a semicrystalline architecture of starch granules. It is known that lesions of the isoamylase1 (ISA1) gene result in accumulation of a water-soluble glucan (WSG) called phytoglycogen instead of amylopectin in various plant species. This type of cereal mutant is referred to as sugary-1 and accumulates a large amount of phytoglycogen in the endosperm. In this study, another WSG-synthesizing mutant has been isolated from japonica rice. This mutant accumulated a significant amount of WSG in the center of endosperm. No significant changes were found in activities of ISA and pullulanase and in the compositions of ISA1 homomer and ISA1-ISA2 heteromer. In addition, activities of starch branching enzyme and starch synthase isoforms were not altered. The accumulated WSG had a specific fine structure, that differed from that of phytoglycogen. Thus, we designated this new mutant as the sugary-2 mutant. Our study results strongly suggest that the Sugary-2 gene product plays an important role in amylopectin synthesis of rice endosperm and identifies a new factor that controls the normal amylopectin structure, especially at the early developmental stage of the endosperm.

Original languageEnglish
Article number1600159
JournalStarch/Staerke
Volume69
Issue number3-4
DOIs
Publication statusPublished - Mar 1 2017

All Science Journal Classification (ASJC) codes

  • Food Science
  • Organic Chemistry

Fingerprint Dive into the research topics of 'Biochemical analysis of new type mutants of japonica rice that accumulate water-soluble α-glucans in the endosperm but retain full starch debranching enzyme activities'. Together they form a unique fingerprint.

  • Cite this