1. Role of Arabidopsis bHLH transcription factors MYC2, MYC3 and MYC4 in defense against herbivory www.unil.ch/reymondlab

2. ABCD Predators Indirect defenses Direct defenses Induction of defense genes Emission of volatile compounds Induced defenses in response to herbivory TFs Jasmonate pathway

3. JA signalling from Staswick, 2008 Stimulus (wound, herbivore)

4. Spodoptera littoralis WT coi1-1 WT coi1-1 Spodoptera littoralis JA signalling is crucial for defense against herbivory The majority of insect-responsive genes are not induced in coi1-1 7 days of larval feeding Reymond et al. (2004) Plant Cell

5. Role of bHLH transcription factors MYC2, MYC3 and MYC4 Growth of Spodoptera littoralis larvae on myc mutants Fernandez-Calvo et al. (2011) Plant Cell Sub-family of Arabidopsis bHLH transcription factors

6. Trancriptome analysis of myc234 mutant Schweizer et al. (2013) Plant Cell The majority of highly dowregulated genes in myc234 are GS-pathway genes

7. Glucosinolate pathway genes are downregulated in myc234 mutant

8. Glucosinolates are defense compounds in Brassicaceae Aliphatic-GS Indole-GS

9. Rapid profiling of intact glucosinolates Glauser et al. (2012) Phytochem Anal UHPLC-QTOFMS

10. Glucosinolate levels are highly reduced in myc234 mutants Constitutive Induced (S. littoralis) Schweizer et al. (2013) Plant Cell

11. MYCs control GS accumulation in seeds

12. Two-choice assay The specialist P. brassicae prefers glucosinolate-containing plants Oviposition Contrasting insect performance on Arabidopsis glucosinolate mutants Schweizer et al. (2013) Plant Cell

13. Change of feeding behaviour of a generalist herbivore Schweizer et al. (2013) Plant Cell Non-uniform ditribution of GS Schroff et al. (2008) PNAS

14. Are GS-related MYBs controlled MYC2,3,4? downregulated genes MYC2 MYC3 MYC4 MYC2 MYC3 MYC4 ? ?

15. MYC2,3,4 physically interact with MYBs Schweizer et al. (2013) Plant Cell but: GS-related MYBs do not interact with JAZs

16. MYC2 binds to the promoter of GS biosynthesis genes ChIP-seq analysis of MYC2-GFP plants CYP79B3 (Atg22330)SOT16 (Atg74100) Consensus MYC binding site (G-box element) GS biosynthesis genes contain MYC- and MYB-binding sites Schweizer et al. (2013) Plant Cell

17. Model for MYC234-dependent activation of glucosinolate genes defense against generalist herbivores

18. Role of other insect-inducible transcription factors S. littoralis performance S. littoralis-induced genes Schweizer et al. (2013) Front. Plant Sci.

19. A hierarchy of transcription factors MYBs glucosinolates

20. Acknowledgements Fabian Schweizer Gaetan Glauser & Ted Turlings SPSW Chemical Analysis Service, Neuchâtel Patricia Fernandez-Calvo & Roberto Solano Dept. of Plant Molecular Genetics, Madrid Mark Zander, Mathew Lewsey & Joe Ecker The Salk Institute, La Jolla (CA)