Transcription Factors and Gene Regulatory Networks
Dr. Salma Balazadeh and her group investigate transcription factors (TFs) which together with their downstream target genes constitute gene regulatory networks (GRNs) that control a vast spectrum of biological processes and often include intricate feedback and feed-forward control loops that link their activity to developmental and physiological processes. Identifying GRNs and analysing theirdynamic integration into cellular activities is thus of great interest in biology.
Our group focuses on unravelling such regulatory loops in model and crop plants, using a broad-spectrum molecular-biological and genomic approach, supported by bio-computational analyses. In addition, we are developing synthetic GRNs for implementation in plant and microbial systems.
The group has four major research areas:
- Gene regulatory networks underlying plant senescence
- Abiotic stress and ROS signalling
- Gene regulatory networks controlling tomato fruit development
- Synthetic GRNs
1. Gene regulatory networks underlying plant senescence
Senescence in plants is a highly regulated process that involves the coordinate expression of a large number of genes. Our group studies TFs regulating leaf senescence in Arabidopsis thaliana, with a focus on NAC TFs which appeared to be particularly important for this process. Notably, of the 106 NAC genes in Arabidopsis, the expression of more than 20 is enhanced during leaf senescence. Several of the senescence-enhanced NAC TFs are also strongly induced by hydrogen peroxide (H2O2), linking this research to our second focus area (see below).
We recently reported the senescence-regulatory functions of the NAC transcription factors ORE1, ORS1 and JUB1. Our current emphasis is on elucidating the details of their GRNs, using a combined set of molecular, biochemical and physiological methods.
- ORE1 – a key positive regulator of leaf senescence
- JUB1 – a transcription factor positively regulating longevity
2. Abiotic stress and ROS signalling
Abiotic stress is one of the prevailing factors limiting crop yield world-wide. Understanding the signalling mechanisms that trigger responses to environmental stress and unravelling the cellular processes with which plants counteract stress impact is thus of great importance for securing global food supply. Our group studies the role of transcription factors and reactive oxygen species (ROS) with a focus on hydrogen peroxide (H2O2), an important signalling molecule, in these processes.
3. Gene regulatory networks controlling tomato fruit development
The tomato fruit represents a general model for fleshy fruit development. Our group has recently initiated research on tomato transcription factors (TFs) with the goal to identify fruit development-related functions of so far uncharacterized TFs. A central aim of the work is the identification of the gene regulatory networks controlled by the chosen TFs.
4. Synthetic GRNs
The general role of transcription factors as master regulators of cohorts of target genes, e.g. along metabolic pathways or for building molecular cellular machines, is of particular relevance also in the field of synthetic biology. Our group utilizes synthetic transcription factors, made by reshuffling bacterial TALEs (transcription activator-like effectors), to establish novel GRNs in plants. The long-term goal here is to control abiotic stress response pathways in plants while at the same time minimizing unwanted effects on development.