Regulation of expression of the tobacco Tnt1 retrotransposon in heterologous species following pathogen-related stresses

Abstract

Transcriptional regulation of the tobacco retrotransposon Tnt1 was monitored in Arabidopsis thaliana and Lycopersicon esculentum. In these two heterologous host species, Tnt1 expression is developmentally regulated, and its tissue-specific pattern of transcription is similar to that observed in tobacco, with the exception that Tnt1 is expressed in their flowers. Induction of Tnt1 by microbial elicitors, previously found in tobacco, is maintained in Arabidopsis and tomato. Tnt1 activation is not strictly dependent upon a Hypersensitive Response-like necrotic response, but also occurs in a plant-pathogen compatible interaction triggered by viral or bacterial infections. The putative role of Tnt1 in generating genetic variability in its host plant is discussed.