Cloning, characterization and genetic engineering of FLC homolog in Thellungiella halophila

The halophyte Thellungiella halophila is used as a model for the study of salt tolerance in plants. However, it flowers late and requires vernalization to promote flowering. In Arabidopsis thaliana, a close relative of T. halophila, FLC is the key gene controling the vernalization response pathway. Here, we report the cloning and functional characterization of T. halophila FLC gene (ThFLC). ThFLC showed significant homology to AtFLC and was negatively regulated upon vernalization treatment. Ectopic expression of ThFLC in Arabidopsis functionally complemented FLC-Ler and caused a late-flowering phenotype. An RNAi construct, developed from a 309 bp fragment of ThFLC cDNA, was used for gene specific silencing of endogenous ThFLC in T. halophila. In transgenic T. halophila plants the endogenous ThFLC transcript was eliminated, producing an early flowering phenotype while retaining the same salt tolerance as wild-type. This engineered T. halophila provides a better research model for plant salt tolerance studies than wild-type T. halophila.