Mechanism for production of starch-like reserve polysaccharide in some cyanobacteria

2015 Fiscal Year Final Research Report

• Project/Area Number: 25440193
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Evolutionary biology
• Research Institution: Akita Prefectural University
• Principal Investigator: Suzuki Eiji 秋田県立大学, 生物資源科学部, 教授 (60211984)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: 貯蔵多糖 / 澱粉 / グリコーゲン / 光合成 / 原核生物 / 細菌 / シアノバクテリア

Outline of Final Research Achievements

The present study was conducted to elucidate the mechanism by which a limited number of cyanobacteria (photosynthetic microorganisms) produce starch-like reserve polysaccharide seen in plants instead of glycogen in most bacteria. Genomic sequences were determined for two starch-producing strains, and the starch production was found to be tightly correlated to the coordinated expression of multiple (2 - 3) isoforms of branching enzyme. Heterologous expression system for starch metabolism genes (starch synthase I and branching enzyme I of rice, and debranching enzyme glgX2 of Cyanobacterium CLg1) was developed in glycogen-producing cyanobacterial strais. Growth conditions were devised to stimulate starch production under deprivation of inorganic nutrients. Finally, recombinant forms of branching enzyme were characterized; form 1 and 2 branching enzymes transferred short oligosaccharides, while the activity of form 3 enzyme was low but it transferred short and long glucan chains.

Free Research Field

植物生理学