TY  - JOUR
A1  - Böhm, Jennifer
A1  - Scherzer, Sönke
A1  - Krol, Elzbieta
A1  - Kreuzer, Ines
A1  - von Meyer, Katharina
A1  - Lorey, Christian
A1  - Mueller, Thomas D.
A1  - Shabala, Lana
A1  - Monte, Isabel
A1  - Solano, Roberto
A1  - Al-Rasheid, Khaled A. S.
A1  - Rennenberg, Heinz
A1  - Shabala, Sergey
A1  - Neher, Erwin
A1  - Hedrich, Rainer
T1  - The Venus flytrap Dionaea muscipula counts prey-induced action potentials to induce sodium uptake
JF  - Current Biology
N2  - Carnivorous plants, such as the Venus flytrap (Dionaea muscipula), depend on an animal diet when grown in nutrient-poor soils. When an insect visits the trap and tilts the mechanosensors on the inner surface, action potentials (APs) are fired. After a moving object elicits two APs, the trap snaps shut, encaging the victim. Panicking preys repeatedly touch the trigger hairs over the subsequent hours, leading to a hermetically closed trap, which via the gland-based endocrine system is flooded by a prey-decomposing acidic enzyme cocktail. Here, we asked the question as to how many times trigger hairs have to be stimulated (e.g., now many APs are required) for the flytrap to recognize an encaged object as potential food, thus making it worthwhile activating the glands. By applying a series of trigger-hair stimulations, we found that the touch hormone jasmonic acid (JA) signaling pathway is activated after the second stimulus, while more than three APs are required to trigger an expression of genes encoding prey-degrading hydrolases, and that this expression is proportional to the number of mechanical stimulations. A decomposing animal contains a sodium load, and we have found that these sodium ions enter the capture organ via glands. We identified a flytrap sodium channel DmHKT1 as responsible for this sodium acquisition, with the number of transcripts expressed being dependent on the number of mechano-electric stimulations. Hence, the number of APs a victim triggers while trying to break out of the trap identifies the moving prey as a struggling Na\(^+\)-rich animal and nutrition for the plant.
KW  - jasmonic acid biosynthesis
KW  - gene expression
KW  - signal transduction
KW  - transporters
KW  - Arabidopsis
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-190870
VL  - 26
IS  - 3
ER  - 
TY  - JOUR
A1  - Berendzen, Kenneth W.
A1  - Weiste, Christoph
A1  - Wanke, Dierk
A1  - Kilian, Joachim
A1  - Harter, Klaus
A1  - Dröge-Laser, Wolfgang
T1  - Bioinformatic cis-element analyses performed in Arabidopsis and rice disclose bZIP- and MYB-related binding sites as potential AuxRE-coupling elements in auxin-mediated transcription
N2  - Background: In higher plants, a diverse array of developmental and growth-related processes is regulated by the plant hormone auxin. Recent publications have proposed that besides the well-characterized Auxin Response Factors (ARFs) that bind Auxin Response Elements (AuxREs), also members of the bZIP- and MYB-transcription factor (TF) families participate in transcriptional control of auxin-regulated genes via bZIP Response Elements (ZREs) or Myb Response Elements (MREs), respectively. Results: Applying a novel bioinformatic algorithm, we demonstrate on a genome-wide scale that singular motifs or composite modules of AuxREs, ZREs, MREs but also of MYC2 related elements are significantly enriched in promoters of auxin-inducible genes. Despite considerable, species-specific differences in the genome structure in terms of the GC content, this enrichment is generally conserved in dicot (Arabidopsis thaliana) and monocot (Oryza sativa) model plants. Moreover, an enrichment of defined composite modules has been observed in selected auxin-related gene families. Consistently, a bipartite module, which encompasses a bZIP-associated G-box Related Element (GRE) and an AuxRE motif, has been found to be highly enriched. Making use of transient reporter studies in protoplasts, these findings were experimentally confirmed, demonstrating that GREs functionally interact with AuxREs in regulating auxin-mediated transcription. Conclusions: Using genome-wide bioinformatic analyses, evolutionary conserved motifs have been defined which potentially function as AuxRE-dependent coupling elements to establish auxin-specific expression patterns. Based on these findings, experimental approaches can be designed to broaden our understanding of combinatorial, auxin-controlled gene regulation.
KW  - Arabidopsis
KW  - Cis-elements
KW  - cis-element modules
KW  - Auxin-regulated transcription
KW  - AuxRE
KW  - bZIP
KW  - MYB
KW  - MYC
Y1  - 2012
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-75138
ER  -