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Modulation of chlorophyll synthesis and its effect on the biogenesis of two photosystems

Research Project

Project/Area Number 08836006
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field 光生物学
Research InstitutionOsaka University

Principal Investigator

FUJITA Yuichi  Osaka University, Institute for Protein Research, Instructor, たんぱく質研究所, 助手 (80222264)

Project Period (FY) 1996 – 1997
Project Status Completed (Fiscal Year 1997)
Budget Amount *help
¥2,400,000 (Direct Cost: ¥2,400,000)
Fiscal Year 1997: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1996: ¥1,700,000 (Direct Cost: ¥1,700,000)
Keywordschlorophyll / protochlorophyllide reductase / Plectonema boryanum / cyanobacterium / photosystem / Plectonema boryanum / 黄化 / クロロフィル合成 / 33-kD蛋白質 / PsaC蛋白質 / プロトクロロフィリド還元 / 緑化
Research Abstract

1. Physiological roles of the two protochlorophyllide reduction systems
Cyanobacteria have two protochlorophyllide (Pchlide) reductases catalyzing the conversion of Pchlide to chlorophyllide, a key step in the biosynthetic pathway of chlorophyll (Chl) ; a light-dependent (LPOR) and a light-independent (DPOR) reductase. Gene (por) encoding LPOR has been cloned from Plectonema boryanum, and a por-disrupted mutant, YFP12, was isolated by target mutagenesis to compare phenotype of YFP12 with those of wild-type and a chlL-disrupted (DPOR-less) mutant, YFC2. YFP12 grew as well as wild type under low light conditions, but not under high light conditions (>130 mu E m^<-2>s^<-1>). In contrast, YFC2 was able to grow under both light conditions. These results suggested that, although both the reductases contributed to Chl synthesis in the cells growing in the light, LPOR was essential for the cells to grow under the high light intensity.
2. Analysis of the construction of the photosystems under a limitation of Chl availability.
YFC2 lacking DPOR was etiolated to reduce the Chl content less than 0.5% of the original level when this mutant was continued to grow under dark for a number of generations. Under this etiolating process, we analyzed the construction of two photosystems, PSI and PSII.Polypeptides of PSII,CP43 and 33 kDa subunit were contained at the level comparable to wild type, while those of PSI,PsaA/PsaB and PsaC were reduced an undetectable level by western analysis. This results suggested that the limitation of Chl supply resulted in the preferential degradation of PSI.

Report

(3 results)
  • 1997 Annual Research Report   Final Research Report Summary
  • 1996 Annual Research Report
  • Research Products

    (9 results)

All Other

All Publications (9 results)

  • [Publications] Y.Fujita: "Cloning of the gene encoding a protochlorophyllide reductase" Plant Cell Physiology. 39(2). 177-185 (1998)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] Y.Fujita: "Protochlorophyllide reduction:a key step in the greening of plants" Plant Cell Physiology. 37. 411-421 (1996)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] Y.Fujita: "Identification of the chlB gene and the gene product essential for the light-independent chlorophyll biosynthesis in the cyanobacterium Plectonema boryanum" Plant Cell Physiology. 37. 313-323 (1996)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] Y.Fujita: "Cloning of the gene encoding a protochlorophyllide reductase" Plant Cell Physiology. 39 (2). 177-185 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] Y.Fujita: "Protochlorophyllide reduction : a key step in the greening of plants" Plant Cell Physiology. 37. 411-421 (1996)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] Y.Fujita: "Identification of the chlB gene and the gene product essential for the light-independent chlorophyll biosynthesis in the cyanobacterium Plectonema boryanum" Plant Cell Physiology. 37. 313-323 (1996)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] Y.Fujita: "Cloning of the gene encoding a protochlorophyllide reductase" Plant Cell Physiology. 39(2). 117-185 (1998)

    • Related Report
      1997 Annual Research Report
  • [Publications] Y.Fujita: "Identification of the chlB gene and the gene product essential for the light-independent chlorophyll biosynthesis in the cyanobacterium Plectonema boryanum." Plant and Cell Physiology. 37巻3号. 313-323 (1996)

    • Related Report
      1996 Annual Research Report
  • [Publications] Y.Fujita: "Protochlorophyllide reduction : a key step in the greening of plants" Plant and Cell Physiology. 37巻4号. 411-421 (1996)

    • Related Report
      1996 Annual Research Report

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Published: 1996-04-01   Modified: 2016-04-21  

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