Defence signalling marker gene responses to hormonal elicitation differ between roots and shoots

15 p., 5 tablas, 3 figurasPhytohormones such as jasmonic acid (JA), salicylic acid (SA), ethylene (ET) and abscisic acid (ABA) play a key role in regulation of plant immune responses to different attackers. Extensive research over recent years has led to the identification of molecular markers for specific hormonal-regulated defence pathways. However, most of our current knowledge on the regulation of plant immunity derives from studies focused on above-ground organs, mainly on the model plant Arabidopsis thaliana. Therefore, it is unclear whether the paradigms based on experiments on above-ground organs are entirely transferable to roots. Here, we used the non-model plant Brassica rapa to study the regulation dynamics of hormonal-related marker genes in both roots and shoots. These markers were identified in Arabidopsis shoots after elicitation of the JA-, SA-, ET- or ABA-signalling pathways, and are commonly used to study induced responses. We assessed whether the regulation of those genes by hormonal elicitation differs between roots and shoots. To discern whether the differences in marker gene expression between roots and shoots are related to differences in hormone production or to differential responsiveness, we also measured actual hormone content in the treated tissue after elicitation. Our results show that some of the widely used markers did not show specific responsiveness to single hormone applications in B. rapa. We further found that hormonal elicitation led to different response patterns of the molecular markers in shoots and roots. Our results suggest that the regulation of some hormonal-related marker genes in B. rapa is organ specific and differs from the Arabidopsis-derived paradigms.This research was supported by the German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena- Leipzig funded by the German Research Foundation Downloaded from https://academic.oup.com/aobpla/article-abstract/10/3/ply031/4996589 by 81263630 user on 16 April 2019 Papadopoulou et al. – Hormonal marker genes in shoots and roots AoB PLANTS https://academic.oup.com/aobpla © The Author(s) 2018 13 (FZT 118). A.M.-M. further acknowledges the support by the programme to support junior researchers to obtain third-party funding from Friedrich-Schiller-Universität Jena (DRM/2015-02). The authors acknowledge support from the iDiv Open Science Publication Fund.Peer reviewe