Heribert Hirt - Research
Stress Response and Signal Transduction of Plants
In contrast to animals, plants are sessile organisms and cannot move away
from adverse environmental conditions. Therefore, plants heavily rely on
high sensitivity detection and adaptation mechanisms to environmental
perturbations. The goals of our research are to understand the molecular
mechanisms of how plants sense, transduce and adapt to changes in
environmental conditions such as UV, cold, drought, heat, salinity, pests
and pathogens. We aim to understand how plants perceive and transmit
stress signals, how plants regulate stress gene expression, and what
function stress metabolites and protein products have in conferring stress
tolerance. We believe that a thorough understanding of these processes
will provide a solid basis to help secure agriculture and environment
under changing global conditions.
Perception and Transduction of Stress Signals
Plants encounter a wide range of abiotic stresses, including
drought, cold, and salt etc., and biotic stresses such as plant
pathogen attacks. To adapt to these stresses, plants use diverse
and sophisticated strategies for recognizing and responding to
these stresses. Sensing of environmental stresses may occur at the
point of initial stress perception itself. Plants might perceive
the stresses in different ways, such as by plasma membrane located
receptors, intracellular or cytoskeleton-associated proteins.
Stress perception is transmitted by signal cascades into altered
gene expression programmes ultimately resulting in metabolic
adjustment and altered physiological responses. Plants have evolved
distinct mechanisms by which tolerance against different stresses
can be achieved. Knowledge about the signal transduction pathways
induced by different stresses is essential to improve plant
tolerance to distinct abiotic and biotic stresses. Although our
understanding of the signalling pathways has increased rapidly over
recent years by joining genetic, biochemical and cell biology
disciplines, we are still far away from a complete understanding
how perception and signalling of environmental stresses is achieved
in plants. Using latest genomic, proteomic and metabolomic
technology, we are searching for sensors and signalling components
of environmental stresses. The major goals of the group are to
elucidate the signalling pathways associated with abiotic and
biotic stresses.
Regulation of Stress Gene Expression
Plants are capable of adapting to a variety of stresses by
inducing specific sets of genes that play key roles in the
adaptation process of plants against diverse stimuli including
biotic and abiotic stresses. By transcriptome profiling and
phosphoproteomics of defined signalling mutants, we try to uncover
the mechanisms how stress signalling is coupled to the
transcriptional machinery with the ultimate aim for improving plant
stress tolerance. Specific aims are the characterization of the
transcriptional mechanisms in the regulation of reactive oxygen
species involved in abiotic and biotic stresses.
Plant Stress Tolerance: Metabolites and Protein Products
The adaptation mechanisms that provide protection against
abiotic and biotic stresses involve complex responses, including
changes in cell cycle, developmental programmes, as well as the
induction of stress and defense genes and the accumulation of
stress metabolites. The functions of the stress metabolites and
stress protein factors accumulating under particular stresses are
still poorly understood. Using high-end metabolite and proteome
screening techniques, we are trying to identify novel metabolites
and protein factors induced by particular stresses and investigate
their properties in a functional context.
