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Molecular Breeding of Disease Resistant Plants with Regulation of Small G-protein, Rac.

Research Project

Project/Area Number 13660048
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field 植物保護
Research InstitutionMie University

Principal Investigator

KOBAYASHI Issei  Mie University, Faculty of Bioresources, Associate Professor, 生物資源学部, 助教授 (90205451)

Project Period (FY) 2001 – 2002
Project Status Completed (Fiscal Year 2002)
Budget Amount *help
¥3,700,000 (Direct Cost: ¥3,700,000)
Fiscal Year 2002: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2001: ¥2,800,000 (Direct Cost: ¥2,800,000)
KeywordsSmall G-protein / PR protein / Salicylic acid / Tobacco
Research Abstract

A small G-protein, Rac, has been known as a key regulator of immune system mediated by the cytoskeleton and NADPH oxidase in animals. In plant defense system, details of Rac functions are still unclear, although a possibility that plant Rac proteins regulate superoxide generation in infected tissues has been pointed out. In this research, to determine the function of plant Rac proteins in defense responses, systemic aquired resistance (SAR) and local aquired resistance (LAR) of tobacco Rac-overexpressor were investigated. When Rac-overexpressor was inoculated with a pathogenic bacterium, Pseudomonas syringae pv tabaci (Psf), higher level of PR gene was expressed and LAR was induced much quicker than wild type plant inoculated with Pst. Moreover, inoculation of a nonpathogen, Pseudomonas syringae pv glycinea, to lower leaves of Rac-overexpressor cause PR-gene expression in upper leaves. Both acidic PR mRNA and salicylic acid prominently accumulated in the upper leaves of inoculated Rac-overexpressor, whereas no accumulation was detected in a wild type, SR-1, tobacco. These results indicate that SAR was induced in Rac overexpressed tobacco by the inoculation with nonpathogenic Pseudomonas, although the nonpathogen doesn't induce SAR in wild type tobacco. These results also suggest that SA-mediated defense reactions might be easily induced in Rac-overexpressor. To confirm the hypothesis, we investigated SA sensitivity of tobacco plants. SA sensitivity of Rac-overexpressor was enhanced to 10 times higher than wild type tobacco. The enhacement of SA sensitivity should be the main reason of the stronger defense reactions in Rac-overexpressor. Taken together, it is suggested that Rac small G-proteins play an important role in the signal perception of the SA-mediated defense system. Moreover, these results suggest the possibility that Rac genes have promise as a target of molecular bleeding of disease resistant crops.

Report

(3 results)
  • 2002 Annual Research Report   Final Research Report Summary
  • 2001 Annual Research Report
  • Research Products

    (3 results)

All Other

All Publications (3 results)

  • [Publications] Kobayashi, I: "Actin-related defense mechanism to reject Penetration attempt by a nonpathogen is maintained in tobacco BY-2 cells"Planta. (In press). (2003)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] Kobayashi,I and Hakuno,F: "Actin-related defense mechanism to reject penetration attempt by a nonpathogen is maintained in tobacco BY-2 cells"Planta. in press. (2003)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] Kobayashi, I: "Actin-related defense mechanism to reject penetration attempt by a nonpathogen is maintained in tobacco BY-2 cells"Planta. (in press). (2003)

    • Related Report
      2002 Annual Research Report

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Published: 2001-04-01   Modified: 2016-04-21  

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