Abstract
PnTFL1, an ortholog of TERMINAL FLOWER 1 (TFL1) in Lombardy poplar (Populus nigra L. var. italica Koehne) was cloned to evaluate its function in poplar. RT-PCR studies showed that the gene was mainly expressed in roots, stems, apical buds and lateral buds. The transgenic Arabidopsis that over-expressed the gene for PnTFL1 decelerated flowering as well as TFL1 over-expressing Arabidopsis. To determine that PnTFL1 acts as TFL1 in lombardy poplar, we constructed binary vectors generating RNAs capable of duplex formation of sequence specific for the PnTFL1 cDNA under control of the cauliflower mosaic virus 35S promoter. The resultant plasmids were introduced into a female clone of Lombardy poplar. Some transgenic lines showed early flowering phenotype that flowered within five months. The most severe transgenic line flowered within five weeks after vegetative propagation by cutting in phytotron, and it also showed late growth, light-green leaves and abnormal leaf shape.
