3 research outputs found
Isolierung und Charakterisierung des putativen Transkriptionsfaktorgens R18 aus der Wiederauferstehungspflanze Craterostigma plantagineum Hochst.
Retrotransposons and siRNA have a role in the evolutionof desiccation tolerance leading to resurrection of the plantCraterostigma plantagineumTobias
\u2022 Craterostigma plantagineum can lose up to 96% of its water content but fully
recover within hours after rehydration. The callus tissue of the plant becomes
desiccation tolerant upon pre-incubation with abscisic acid (ABA). In callus and
vegetative organs, ABA addition and water depletion induce a set of dehydrationresponsive
genes.
\u2022 Previously, activation tagging led to the isolation of Craterostigma desiccation
tolerant (CDT-1), a dehydration-related ABA-inducible gene which renders callus
desiccation tolerant without ABA pre-treatment. This gene belongs to a family of
retroelements, members of which are inducible by dehydration.
\u2022 Craterostigma plantagineum transformation with mutated versions of CDT-1
indicated that protein is not required for the induction of callus desiccation tolerance.
Northern analysis and protoplast transfection indicated that CDT-1 directs the
synthesis of a double-stranded 21-bp short interfering RNA (siRNA), which opens
the metabolic pathway for desiccation tolerance.
\u2022 Via transposition, these retroelements have progressively increased the capacity of
the species to synthesize siRNA and thus recover after dehydration. This may be a case
of evolution towards the acquisition of a new trait, stimulated by the environment
acting directly on intra-genomic DNA replication