Expression profiling of the Arabidopsis Mediator complex mutant pft1/med25 and wildtype infected with Fusarium oxysporum

The Mediator complex is an evolutionary conserved multiprotein complex that plays an essential role in initiating and regulating transcription. Its function is to act as a universal adaptor between RNA Polymerase II and DNA-bound transcription factors to translate regulatory information from activators and repressors to the transcriptional machinery. We have found that the PFT1 gene (which encodes the MED25 subunit of the Mediator complex) is required for the uncompromised expression of both salicylic acid- and jasmonate-dependent defense genes as well as resistance to the leaf-infecting fungal pathogens, Alternaria brassicicola and Botrytis cinerea in Arabidopsis. Surprisingly, we found that the pft1/med25 mutant showed increased resistance to the root infecting pathogen Fusarium oxysporum and that this resistance was independent of classical defense genes. In addition, the over-expression of PFT1 led to increased susceptibility to F. oxysporum. Therefore, to explore this phenomenon further, we wished to use whole genome transcript profiling to identify which genes may be playing a role in pft1/med25-mediated resistance to F. oxysporum.

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Kidd BN, Edgar CI, Kumar KK, Aitken EA, Schenk PM, Manners JM, Kazan K