The symbiotic transcription factor MtEFD and cytokinins are positively acting in the Medicago truncatula and Ralstonia solanacearum pathogenic interaction. Issue 4 (11th December 2013)

• Record Type: Journal Article
• Authors: Moreau, Sandra; Fromentin, Justine; Vailleau, Fabienne; Vernié, Tatiana; Huguet, Stéphanie; Balzergue, Sandrine; Frugier, Florian; Gamas, Pascal; Jardinaud, Marie‐Françoise
• Is Part Of: New phytologist. Volume 201:Issue 4(2014)
• Page Start: 1343
• Page End: 1357
• Publication Date: 2013-12-11
• Subjects: cytokinins -- Medicago truncatula -- pathogenesis–symbiosis crosstalk -- Ralstonia solanacearum -- root pathogen -- Sinorhizobium meliloti -- transcriptome; Botany -- Periodicals; 580
• DOI: 10.1111/nph.12636
• Languages: English
• ISSNs: 0028-646X

Abstract

Summary: A plant–microbe dual biological system was set up involving the model legume Medicago truncatula and two bacteria, the soil‐borne root pathogen Ralstonia solanacearum and the beneficial symbiont Sinorhizobium meliloti . Comparison of transcriptomes under symbiotic and pathogenic conditions highlighted the transcription factor Mt EFD (Ethylene response Factor required for nodule Differentiation) as being upregulated in both interactions, together with a set of cytokinin‐related transcripts involved in metabolism, signaling and response. Mt RR4 (Response Regulator), a cytokinin primary response gene negatively regulating cytokinin signaling and known as a target of Mt EFD in nodulation processes, was retrieved in this set of transcripts. Refined studies of Mt EFD and Mt RR4 expression during M. truncatula and R. solanacearum interaction indicated differential kinetics of induction and requirement of central regulators of bacterial pathogenicity, HrpG and HrpB. Similar to Mt RR4, Mt EFD upregulation during the pathogenic interaction was dependent on cytokinin perception mediated by the Mt CRE1 (Cytokinin REsponse 1) receptor. The use of M. truncatula efd‐1 and cre1‐1 mutants evidenced Mt EFD and cytokinin perception as positive factors for bacterial wilt development. These factors therefore play an important role in both root nodulation and root disease development.