Gibberellin A3 as an epigenetic determinant of global DNA hypo-methylation in tobacco

Abstract

Gibberellins (GAs) are a large family of tetracyclic diterpenoids, controlling important aspects of growth and development throughout the plant life cycle. To explore the possibility that gibberellin A3 (GA3) signalling induces epigenetic alteration(s), we carried out a field experiment study using Nicotiana tabacum as a model system. The GA3 application on leaves resulted in increased plant-height, foliage density, leaf cell area, and trichome density. The plants exposed to GA3 also exhibited: 1) increased chromatin de-condensation, 2) reduced global DNA methylation, 3) reduced DNA methyltransferases (NtDNMTs) activities accompanied by decreased amounts of NtMET1 and NtCMT3 transcripts, and 4) partial restoration of phenotype and expression of epigenetically silenced reporter transgene. Based on these observations, we propose that GA3 application induces complex epigenetic re-programming, which may lead to distinct developmental phenotypes. These results could provide an important insight for future studies on epigenetic mechanism(s) in other important crops.

Keywords

• chromatin de-condensation
• dna methyltransferase
• nicotiana tabacum
• leaf cell area
• plant height
• trichome density