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Signal Transduction of Plant Hormone Ethylene Dr. Hongwei Guo Peking University June 22, 2006.

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Presentation on theme: "Signal Transduction of Plant Hormone Ethylene Dr. Hongwei Guo Peking University June 22, 2006."— Presentation transcript:

1 Signal Transduction of Plant Hormone Ethylene Dr. Hongwei Guo Peking University June 22, 2006

2 Plant Growth and Development Highly plastic ----plants cannot run! Perception of environmental signals involves multiple plant hormones environmental signals:  light  gravity  temperature  water  nutrients  touch  Pathogens, etc

3 Plant hormones Classical Five: Auxins Gibberellins (GAs) Cytokinins Abscisic acid (ABA) Ethylene Newly defined: Brassinosteroids Jasmonic acid (JA) Salicylic acid (SA) Nitric oxide (NO) CC H H H H Ethylene (C 2 H 4 ) The simplest molecule on the earth that has a biological function

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5 Ethylene can do more… abscission --Germination --Senescence --Abscission --Nodulation --Stress tolerance --Pathogen defense senescence pathogen defense

6 A simple genetic system Arabidopsis seedling -C 2 H 4 Shortened root and hypocotyl Swollen hypocotyl Exaggerated apical hook …triple response… +C 2 H 4

7 Ethylene Response Mutants ein 10 ein (ethylene insensitive) wild type 5 ctr (constitutive triple response) ctr + C 2 H 4 - C 2 H 4

8 ER EIL1 nucleus cytoplasm A genetic model of ethylene signaling pathway

9 A SCF complex degrades EIN3 protein SCF EBF1/2 EIN3 ethylene response Cullin1 ASK1 EBF1/2 EIN3 Rbx E2 Ub (Guo and Ecker, Cell 2003) 26S proteasome (degraded)

10 C2H4C2H4 Receptors (ETR1/2 ERS1/2 EIN4) CTR1 EIN2 Signals and Stress Target genes EBS EIN3 A working model on the ethylene signaling pathway in Arabidopsis ASK Cul1 Rbx EBF1/2 EBF1/2 mRNA EIN5EIN6? EIL1 (SCF EBF1/2 E3 ligase) (Guo and Ecker, 2004)

11 ERF1 EDFsERFsTFsothers PRsExpansinsHLS1others Receptors/ CTR1 EIN2 EIN3/EIL1 EIL2-5? SAM ACC C2H4C2H4 ACS ACO Defense response Differential growth (hook formation) Cell growth (elongation/ expansion) Other types of ethylene responses SCF EBF EIN5 (RNAi) Primary ethylene response genes environmental stimuli cytokinin auxin deveopmental signals Light Glucose JA SCF COI1

12 Acknowledgments Salk Institute, USA Dr. Joseph Ecker IBMP, France Dr. Pascal Genschik Peking University Fengying An Hongjiang Li Xiaorui Guo Qiuchen Xing UCLA, USA Dr. Chentao Lin


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