Title : DOF Affecting Germination 1: A tool to unravel how plants respond to drought stress in seeds
Abstract:
For most plants including crops, the seed is the starting point of the growth cycle. Seed germination ensures the survival of the next generation, and plants have evolved mechanisms that enable seed germination to be arrested under stress conditions and then resumed when conditions are favourable. Desiccation tolerance is an important trait of plant life, it is defined as the ability to reinduce seed germination after water loss without lethal damage. This capacity is established during maturation of seeds, in the same temporal window in which dormancy is established. The Arabidopsis DOF AFFECTING GERMINATION 1 (DAG1) protein is a key player in the control of the developmental switch between seed dormancy and germination. Indeed, we proved that DAG1 functions in the establishment and maintenance of dormancy by controlling the hormonal balance between GIBBERELLINS (GA) and ABSCISSIC ACID (ABA). We have recently recently discovered that DAG1 also mediates drought tolerance in seeds. Although the molecular mechanisms underlying desiccation tolerance have not been completely elucidated, a number of seed-specific and stress-related proteins are known to be involved in this process as well, namely LEA proteins and the WRKY transcription factors. Interestingly, a genome-wide analysis (RNA-seq) allowed us to identify a number of LEA and WRKY genes as target genes of DAG1, since they are significantly deregulated in the dag1 knock-out mutant. Analysis of the molecular and genetic epistatic relationships between DAG1 and these proteins is in progress. The results of this study will help in unveiling the molecular mechanisms of plant response to drought stress in seeds.
