Novel JAZ co-operativity and unexpected JA dynamics underpin Arabidopsis defence responses to Pseudomonas syringae infection
de Torres Zabala, M
© 2015 The Authors © New Phytologist © 2015 New Phytologist Trust. This is an open access article under the terms of the Creative Commons Attribution License, which permits use,distribution and reproduction in any medium, provided the original work is properly cited.
Pathogens target phytohormone signalling pathways to promote disease. Plants deploy salicylic acid (SA)-mediated defences against biotrophs. Pathogens antagonize SA immunity by activating jasmonate signalling, for example Pseudomonas syringae pv. tomato DC3000 produces coronatine (COR), a jasmonic acid (JA) mimic. This study found unexpected dynamics between SA, JA and COR and co-operation between JAZ jasmonate repressor proteins during DC3000 infection. We used a systems-based approach involving targeted hormone profiling, high-temporal-resolution micro-array analysis, reverse genetics and mRNA-seq. Unexpectedly, foliar JA did not accumulate until late in the infection process and was higher in leaves challenged with COR-deficient P. syringae or in the more resistant JA receptor mutant coi1. JAZ regulation was complex and COR alone was insufficient to sustainably induce JAZs. JAZs contribute to early basal and subsequent secondary plant defence responses. We showed that JAZ5 and JAZ10 specifically co-operate to restrict COR cytotoxicity and pathogen growth through a complex transcriptional reprogramming that does not involve the basic helix-loop-helix transcription factors MYC2 and related MYC3 and MYC4 previously shown to restrict pathogen growth. mRNA-seq predicts compromised SA signalling in a jaz5/10 mutant and rapid suppression of JA-related components on bacterial infection.
We grat efully acknowledge support from the British Biotechnol-ogy and Science Research Council (Grants BB/C514115/1 andBB/F005903/1) and a Chinese Government Studentship to B.Z.The members of the Plant Responses to Environmenta l STressconsortium are thanked for microarray design, labelling and dataextraction. We thank Selena Gimenez-Ibanez for the HopXderivatives, Paul O’Neil for assistance with clustering and OrkunSoyer for helpful discussions. Pathogen work was carried outunder Plant Health License PHL 204B/6739.
This is the final version of the article. Available from Wiley via the DOI in this record.
New Phytologist, 2016, Vol. 209, Issue 3, pp. 1120 - 1134