Unravelling the evolution of desiccation tolerance in higher plants
Water removal from cells is a severe and generally lethal process. Desiccation tolerant organisms have structural, physiological and molecular mechanisms to survive under severe water stress. However, the exact nature of the mechanisms that allow desiccation tolerant organisms to survive the loss of almost all cellular water without dying is still poorly understood.
Desiccation sensitive organisms seem to lack some desiccation tolerance (DT) mechanisms and, thereby, they constitute important models for comparative studies with desiccation tolerant species that are phylogenetically related.
Our aim is to understand the mechanisms underlying DT in seeds and highly desiccation tolerant plants (resurrection plants) using physiological and molecular approaches.
Our study includes Arabidopsis thaliana as a model species for seed DT and Xerophyta viscosa as model for vegetative DT. The main hypothesis underlying this study are:
- Reproductive DT evolved from redirecting pre-existent ancient vegetative DT-related mechanisms from earlier land plants, and later in evolution, resurrection species re-activated these mechanisms in their vegetative tissues.
- Not all, but part of the regulatory DT network is conserved between reproductive and vegetative DT species, and can be switched on in desiccation sensitive tissues.
We focus our research on further investigation of two main findings that support our hypothesis:
1 – The characterization of a protein family related to protection of the cell against water loss in seeds and vegetative tissues – The Late Embryogenesis Abundant (LEA) proteins.
2 – The presence of specific transcription factors activated during water loss in desiccation tolerant plants and seeds.
With the increased desertification, mainly caused by climate change, abiotic stresses such as drought and desiccation are serious threats to agriculture and the environment. Elucidating the genomic basis of plant adaptation to desiccation will provide important information on land plant evolution, and may enable future incorporation of vegetative desiccation tolerance in crops.