ACTIVATION OF PLANT RETROTRANSPOSONS UNDER STRESS CONDITIONS

Activation of retrotransposons by stresses and external change is comm on in all eukaryotes, including plants, The transcriptional activation of several well-characterized plant retrotransposons seems to be tigh tly linked to molecular pathways activated by stress, and activation i s under the control of cis-regulatory sequences strikingly similar to those of plant defence genes. These regulatory sequences are highly va riable, suggesting that retrotransposons could evolve through modifica tion of their regulatory features, As the molecular basis for their re gulation is becoming better understood, it is possible to begin to ass ess the putative biological impact of this stress response.