Function and transcriptional regulation of a plant detoxification program
Final Report Abstract
Plants are challenged by toxic chemicals that are either released by man, neighbouring plants or pathogenic microbes. To alleviate this chemical stress, plants induce the synthesis of detoxifying enzymes and transporters, which facilitate the inactivation and elimination of these harmful compounds. We have based the proposal on our observation that the activation of at least part of this detoxification programme is regulated by members of the TGA family of bZIP transcription factors and the interacting transcriptional co-activator, the GRAS protein SCL14. In the original proposal, we suggested to investigate whether the SCL14/TGA-dependent detoxification program plays a role in responses against other stresses rather than exogenous chemical stress and to elucidate the mechanism that leads to the induction of the detoxification program. First, we did not obtain strong evidence that SCL14 plays a role under biotic or abiotic stress. Therefore we concentrated on the question how treatment with harmful chemicals induces gene expression. The SCL14/TGA complex can play two roles depending on the promoter context and tissue: It can amplify the regulated activity of yet unknown xenobiotic-responsive transcription factors and its activity per se can be regulated by xenobiotic stress. In roots, we observed xenobiotic-dependent translocation of SCL14 into the nucleus. However, this does not seem to be the crucial activating mechanism leading to the onset of induced transcription of target genes. Moreover, we identified SCL14/TGA-regulated transcription factors ANAC032 and ATAF1 as secondary transcription factors within the detoxification program. Last, we identified a novel COI1 function that contributes to the activation of the CYP81D11 promoter independently of JA-Ile at a binding site that is independent of the MYC2 binding site.
Publications
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(2012) Xenobiotic- and jasmonic acid-inducible signal transduction pathways have become interdependent at the Arabidopsis CYP81D11 promoter. Plant Physiol 159: 391-402
Koster J, Thurow C, Kruse K, Meier A, Iven T, Feussner I, Gatz C
