TY  - JOUR
A1  - Weiste, Christoph
A1  - Pedrotti, Lorenzo
A1  - Selvanayagam, Jebasingh
A1  - Muralidhara, Prathibha
A1  - Fröschel, Christian
A1  - Novák, Ondřej
A1  - Ljung, Karin
A1  - Hanson, Johannes
A1  - Dröge-Laser, Wolfgang
T1  - The Arabidopsis bZIP11 transcription factor links low-energy signalling to auxin-mediated control of primary root growth
JF  - PLoS Genetics
N2  - Plants have to tightly control their energy homeostasis to ensure survival and fitness under constantly changing environmental conditions. Thus, it is stringently required that energy-consuming stress-adaptation and growth-related processes are dynamically tuned according to the prevailing energy availability. The evolutionary conserved SUCROSE NON-FERMENTING1 RELATED KINASES1 (SnRK1) and the downstream group C/S\(_{1}\) basic leucine zipper (bZIP) transcription factors (TFs) are well-characterised central players in plants’ low-energy management. Nevertheless, mechanistic insights into plant growth control under energy deprived conditions remains largely elusive. In this work, we disclose the novel function of the low-energy activated group S\(_{1}\) bZIP11-related TFs as regulators of auxin-mediated primary root growth. Whereas transgenic gain-of-function approaches of these bZIPs interfere with the activity of the root apical meristem and result in root growth repression, root growth of loss-of-function plants show a pronounced insensitivity to low-energy conditions. Based on ensuing molecular and biochemical analyses, we propose a mechanistic model, in which bZIP11-related TFs gain control over the root meristem by directly activating IAA3/SHY2 transcription. IAA3/SHY2 is a pivotal negative regulator of root growth, which has been demonstrated to efficiently repress transcription of major auxin transport facilitators of the PIN-FORMED (PIN) gene family, thereby restricting polar auxin transport to the root tip and in consequence auxin-driven primary root growth. Taken together, our results disclose the central low-energy activated SnRK1-C/S\(_{1}\)-bZIP signalling module as gateway to integrate information on the plant’s energy status into root meristem control, thereby balancing plant growth and cellular energy resources.
KW  - root growth
KW  - sucrose
KW  - auxins
KW  - meristems
KW  - regulator genes
KW  - genetically modified plants
KW  - gene expression
KW  - plant growth and development
Y1  - 2017
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-157742
VL  - 13
IS  - 2
ER  - 
TY  - JOUR
A1  - Zhang, Yi
A1  - Lee, Chil-Woo
A1  - Wehner, Nora
A1  - Imdahl, Fabian
A1  - Svetlana, Veselova
A1  - Weiste, Christoph
A1  - Dröge-Laser, Wolfgang
A1  - Deeken, Rosalia
T1  - Regulation of Oncogene Expression in T-DNA-Transformed Host Plant Cells
JF  - PLoS Pathogens
N2  - Virulent Agrobacterium tumefaciens strains integrate their T-DNA into the plant genome where the encoded agrobacterial oncogenes are expressed and cause crown gall disease. Essential for crown gall development are IaaH (indole-3-acetamide hydrolase), IaaM (tryptophan monooxygenase) and Ipt (isopentenyl transferase), which encode enzymes for the biosynthesis of auxin (IaaH, IaaM) and cytokinin (Ipt). Although these oncogenes are well studied as the tumor-inducing principle, nothing is known about the regulation of oncogene expression in plant cells. Our studies show that the intergenic regions (IGRs) between the coding sequences (CDS) of the three oncogenes function as promoters in plant cells. These promoters possess a eukaryotic sequence organization and cis-regulatory elements for the binding of plant transcription factors. WRKY18, WRKY40, WRKY60 and ARF5 were identified as activators of the Ipt promoter whereas IaaH and IaaM is constitutively expressed and no transcription factor further activates their promoters. Consistent with these results, the wrky triple mutant plants in particular, develops smaller crown galls than wild-type and exhibits a reduced Ipt transcription, despite the presence of an intact ARF5 gene. WRKY40 and WRKY60 gene expression is induced by A. tumefaciens within a few hours whereas the ARF5 gene is transcribed later during crown gall development. The WRKY proteins interact with ARF5 in the plant nucleus, but only WRKY40 together with ARF5 synergistically boosts the activation of the Ipt promoter in an auxin-dependent manner. From our data, we propose that A. tumefaciens initially induces WRKY40 gene expression as a pathogen defense response of the host cell. The WRKY protein is recruited to induce Ipt expression, which initiates cytokinin-dependent host cell division. With increasing auxin levels triggered by ubiquitous expression of IaaH and IaaM, ARF5 is activated and interacts with WRKY40 to potentiate Ipt expression and balance cytokinin and auxin levels for further cell proliferation.
KW  - luminescence
KW  - oncogenes
KW  - agrobacterium tumefaciens
KW  - transcription factors
KW  - auxins
KW  - gene expression
KW  - cytokinins
KW  - plant cells
Y1  - 2015
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-125256
VL  - 11
IS  - 1
ER  -