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Dierk Scheel教授講演会(動植物の自然免疫系)@東京理科大学



講師: Prof. Dr. Dierk Scheel
Leibniz Institute of Plant Biochemistry&s_comma; Halle&s_comma; Germany

場所 東京理科大学 野田キャンパス (東武野田線 運河駅下車 徒歩5分; つくばエクスプレス利用の場合、「流山おおたかの森」で東武野田線に乗り換え、3駅目)
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10:40-12:10 講義棟7階 K704教室
Innate immunity has been recognized as an ancient type of pathogen defense in vertebrates and insects. This defense system is based on receptor-mediated recognition of abundant surface components of the pathogen that are not present in the host. These pathogen associated molecular patterns (PAMPs) are of diverse structure and usually of essential importance for the pathogen&s_comma; but not present in the host organism. PAMPs bind to host receptors that share conserved functional domains&s_comma; such as leucine-rich repeat (LRR) motifs and Toll and interleukin-1 receptor (TIR) domains. Upon ligand binding these receptors initiate signal transduction networks that activate a multifaceted defense response. Successful pathogens apparently have developed tools to suppress the innate immune response mostly by interfering with these signaling pathways. The principle as well as individual elements of this ancient defense system have been retained in plants as well.

14:00-15:30 6号館4階 応用生物科学専攻 大学院セミナー室
One obvious example of a PAMP recognized by plants is an abundant extracellular transglutaminase present in mycelial cell walls of many phytopathogenic oomycetes. A short oligopeptide fragment (Pep-13) of this enzyme present in all oomycete transglutaminases analyzed so far was found to be necessary and sufficient for recognition by parsley and potato.
Identical structural elements of Pep-13 are essential for recognition as well as for elicitor and transglutaminase activity. Binding of Pep-13 to its plant plasma membrane receptor initiates branched signal transduction pathways involving calcium channels&s_comma; protein kinase cascades&s_comma; reactive oxygen species&s_comma; salicylate and jasmonate. Complex alterations in gene expression patterns are induced via this signaling network&s_comma; which finally
results in activation of a multicomponent defense response.
A mutagenesis approach was chosen to identify novel components of the non-host disease resistance of Arabidopsis thaliana against Phytophthora infestans. Cytological analysis of wild-type plants challenged with P.
infestans spores revealed that cell wall penetration attempts are usually aborted and only few spores can trigger a hypersensitive response with local cell death. A microscope-based screen for altered-resistance phenotypes resulted in the isolation of several mutants with an enhanced penetration frequency phenotype. Similar phenotypes were also observed upon inoculation of different Arabidopsis ecotypes with P. infestans.

〒278-8510 千葉県野田市山崎2641
東京理科大学 理工学部 応用生物科学科/ゲノム創薬研究センター 細胞シグナル制御
朽津 和幸 (kuchitsu@rs.noda.tus.ac.jp)