ADVANCIS

Microarray datasets and phylogenetic footprinting

Cross-species microarray and mRNA-SEQ datasets are being generated using hydroponically grown plants including A. thaliana, A. halleri and A. lyrata. As a start, we are currently focusing on the comparison of transcriptional responses occurring upon abiotic stimuli, i.e. metal deficiency or metal excess. This seems promising since A. halleri differs fundamentally from A. thaliana and A. lyrata in its metal homeostasis network (see figure 1 below). In future experiments this set-up will be used for the application of different abiotic and biotic stimuli. Sets of genes that are transcriptionally co-regulated in the three different species in response to a given stimulus are identified and then used for the discovery of novel cis-regulatory elements in their upstream promoter sequences.

Figure 1. Arabidopsis thaliana and the closely related hyperaccumulator species A. halleri differ fundamentally in their metal homeostasis network. Photograph of a hydroponic culture of A. thaliana (A) and A. halleri (B). In A. thaliana, with increasing external metal concentrations, plant internal metal concentrations increase mainly in the root (and also in A. lyrata, not shown). A. thaliana is non-tolerant to high metal concentrations in the soil. By contrast, the metal hyperaccumulator A. halleri accumulates high levels of Zn in the shoot even at low external Zn concentrations and tolerates high soil Zn contents (see graph. Graph is not to scale. Talke et al., 2006, Plant Physiol. 142: 148-67).