THE PROMOTER OF THE TOBACCO TNT1 RETROTRANSPOSON IS INDUCED BY WOUNDING AND BY ABIOTIC STRESS

The transcription of the tobacco Tnt1 retrotransposon was previously s hown to be induced, in tobacco and in heterologous species, by microbi al elicitors and by pathogen infections. We report here that the expre ssion of the Tnt1 promoter is also activated in heterologous species s uch as tomato and Arabidopsis by wounding, freezing and by other abiot ic factors known to induce the plant defence response, such as salicyl ic acid, CuCl2, or oxidative stress. A similar regulation is observed in tobacco for most treatments. The induction of the Tnt1 promoter exp ression by wounding remains localized around injury points. In CuCl2-t reated Arabidopsis plants, the transcription of Tnt1 is correlated wit h accumulation of the phytoalexin camalexin and with the expression of the EL13 defence gene. The interest of the Tnt1 promoter as a sensiti ve indicator of the plant defence responses is discussed.