WRKY transcription factors involved in salicylic acid- induced defense gene expression
Verk, M.C. van
Citation
Verk, M. C. van. (2010, June 15). WRKY transcription factors involved in salicylic acid-induced defense gene expression. Retrieved from
https://hdl.handle.net/1887/15688
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WRKY Transcription Factors Involved in Salicylic Acid-Induced
Defense Gene Expression
Marcel Cristiaan van Verk
WRKY Transcription Factors Involved in Salicylic Acid-Induced
Defense Gene Expression
PROEFSCHRIFT
ter verkrijging van
de graad van Doctor aan de Universiteit Leiden,
op gezag van Rector Magnificus prof.mr. P. F. van der Heijden, volgens besluit van het College voor Promoties
te verdedigen op dinsdag 15 juni 2010 klokke 13:45 uur
door
Marcel Cristiaan van Verk
geboren te Dordrecht
in 1980
Samenstelling promotiecommissie:
Promotors: Prof. dr. J. Memelink Prof. dr. J.F. Bol Co-promotor: Dr. H.J.M. Linthorst
Overige leden: Dr. I.E. Somssich (Max Planck Institute, Cologne) Prof. dr. ir. L.C. van Loon (Utrecht University) Prof. dr. P.J.J. Hooykaas
Prof. dr. E. van der Meijden
This work was carried out in the graduate school of Experimental Plant Sciences Cover design by Roy Korpel, 2D Digital Artist, www.roykorpel.nl
Printed and bound by Wöhrmann Print Service, Zutphen, the Netherlands
ISBN: 978-90-8570-567-3
Aan mijn ouders
CONTENTS Chapter 1
Transcriptional Regulation of Plant Defense Responses 11
• Abstract 13
• Plant Immune Signaling Pathways 13
• Defense Signaling Regulatory Compounds 15
• Jasmonate Signal Transduction 15
• Ethylene Signal Transduction 17
• SA Signal Transduction 18
• Transcription Factors Regulating Plant Defense Gene Expression 21
• AP2/ERF Transcription Factors 21
• MYB Transcription Factors 23
• MYC Transcription Factors 25
• bZIP Transcription Factors 25
• WRKY Transcription Factors 27
• Regulation of Plant Defenses at the Chromosomal Level 30
• Chromatin Modifications and Gene Expression 30
• Chromatin Modifications in Plants 31
• Chromatin Modifications at Promoters Involved in Innate Immunity 34
• The SA pathway 34
• The JA pathway 36
• Acknowledgment 37
Chapter 2
A Novel WRKY Transcription Factor Is Required for Induction of
PR-1a Gene Expression by Salicylic Acid and Bacterial Elicitors 39
• Abstract 41
• Introduction 41
• Results 43
• A Novel WRKY Factor Binds to the PR-1a Promoter 43
• Characterization of NtWRKY12 Binding Sites in the PR-1a Promoter 44
• Role of NtWRKY12 and TGA1a in SA-Induced PR-1a Expression 48
• Role of NtWRKY12, TGA1a, and Myb1 Factors in Elicitor-Induced
PR-1a Expression 50
• NtWRKY12 Activates PR-1a::GUS Gene Expression in Arabidopsis
Protoplasts 52
• Discussion 53
• DNA Binding Site of NtWRKY12 53
• NtWRKY12 Contains a Variant WRKY Domain 54
• Role of NtWRKY12 in PR-1a Gene Expression 55
• NtWRKY12 Is a Transcriptional Activator of PR-1a Gene Expression 57
• Occurence of the WK Box in Other Promoters 58
• Conclusion 59
• Materials and Methods 59
Chapter 3
Tobacco Transcription Factors NtWRKY12 and TGA2.2 Interact
in vitro and in vivo and Activate PR-1a Gene Expression 65
• Abstract 67
• Introduction 67
• Results 69
• Protein-Protein Interactions Between NtWRKY12, TGAs and NPR1 69
• Functional Domains of NtWRKY12 72
• PR-1a::GUS Gene Expression in Arabidopsis Protoplasts Cotransfected with Plasmids Encoding NtWRKY12, NtNPR1 and TGAs 74
• Role of the WK and as-1-like Boxes in the Activation of the PR-1a
Promoter by NtWRKY12 and TGA2.2 77
• Discussion 80
• Materials and Methods 83
• Acknowledgements 84
Chapter 4
Prospecting for Genes Involved in Transcriptional Regulation of Plant
Defenses, a Bioinformatics Approach 87
• Abstract 89
• Introduction 89
• Results and Discussion 90
• Public Microarray Data Selection 90
• Target Gene Selection and Co-expression Cutoff Determination 93
• Exploration of Co-expressed Closest Neighbor Transcription Factors
of Regulatory Genes 93
• The MAP Kinase Pathway 94
• The JA Biosynthesis Pathway 98
• The ET Biosynthesis and Signaling Pathway 98
• The SA Biosynthesis Pathway 101
• Concluding Remarks 103
• Materials and Methods 104
• Acknowledgements 104
Chapter 5
WRKY Transcription Factors Involved in Activation of SA
Biosynthesis Genes 111
• Abstract 113
• Introduction 113
• Results 115
• WRKY28 Activates ICS1::GUS Gene Expression in Arabidopsis Protoplasts 115
• Characterization of the WRKY28 Binding Sites in the ICS1 Promoter 115
• Chromatin Immunoprecipitation Analysis of WRKY28 122
• Discussion 123
• WRKY28 and WRKY46 Activate Expression of ICS1 and PBS3, Respectively 123
• DNA Binding Site of WRKY28 124
• Integrated Model for Regulation of SA Biosynthesis by
WRKY28 and WRKY46 125
• Materials and Methods 125
• Acknowledgements 128
Chapter 6
Summary 131
Chapter 7
Samenvatting 137
Chapter 8
Bibliography 143
Chapter 9
Curriculum Vitae 171
