The Arabidopsis bZIP11 Transcription Factor Links Low-Energy Signalling to Auxin-Mediated Control of Primary Root Growth - ISRR 2018 10th Symposium for the International Society of Root Research

Christoph Weiste ¹ Lorenzo Pedrotti ¹ Jebasingh Selvanayagam ² Prathibha Muralidhara ¹ Christian Fröschel ¹ Ondřej Novák ³ Karin Ljung ³ Johannes Hanson ⁴ Wolfgang Dröge-Laser ¹

¹Julius-von-Sachs Institut, Pharmazeutische Biologie, Julius-Maximilians-Universität Würzburg, Germany
²Department of Molecular Plant Physiology, Utrecht University, Netherlands
³Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Umeå Plant Science Centre, Sweden
⁴Department of Plant Physiology, Umeå University, Umeå Plant Science Centre, Sweden

To cope with fluctuating environmental conditions, plants must tightly regulate their energy homeostasis to guard their survival. It is thus important for plants to tune their energy consuming catabolic processes, such as stress-adaptation and growth depending on the available energy resources. SUCROSE NON-FERMENTING RELATED KINASES1 (SnRK1) and their downstream targets group C/S1 basic leucine zipper (bZIP) transcription factors (TFs) are well characterised central players in low energy management in plants¹. However, it remains unclear how plants control or promote growth during energy deprived conditions. In this present study, we have shown a novel function of the low energy activated group S1 TFs as regulators of auxin-mediated primary root growth.

Transgenic gain-of-function approaches of the low-energy controlled bZIP11 shows root growth repression by restricting the growth of root apical meristem, but the root growth of loss-of-function plants show an increased insensitivity to low-energy conditions. Furthermore, molecular analyses revealed that bZIP11 control starvation-induced expression of IAA3/SHY2. By gaining control over this pivotal negative regulator of the root meristem activity, bZIP11 repress the major auxin transport facilitators of the PIN-FORMED (PIN) gene family and restrict polar auxin transport to the root tip and thereby auxin-driven primary root growth. These results show that the central SnRK1-C/S1-bZIP low-energy-signalling module as key to integrate information on the plants energy status into root meristem control and balancing plant growth and cellular energy resources²

^1. Snf1-RELATED KINASE1- Controlled C/S1-bZIP Signaling Activates Alternative Mitochondrial Metabolic Pathways to Ensure Plant Survival in Extended Darkness

Pedrotti L, Weiste C, Naegele T, Wolf E, Lorenzin F, Dietrich K, Mair A, Weckwerth W, Teige M, Baena-Gonzalez E, Droege-Laser W. Plant Cell. 2018.

2 The Arabidopsis bZIP11 transcription factor links low-energy signalling to auxin-mediated control of primary root growth

Weiste C, Pedrotti L, Selvanayagam J, Muralidhara P, Fröschel C, et al. (2017) The Arabidopsis bZIP11 transcription factor links low-energy signalling to auxin-mediated control of primary root growth. PLOS Genetics 13(2)