Cloning and expression analysis ofLEAFYhomologue in Pak Choi (Brassica rapasubsp. chinensis)

LEAFY is a floral meristem identity gene in Arabidopsis thaliana, which plays a key role during flowering. BrcLEAFY (BrcLFY), a FLO/LFY homologue, was cloned from Pak Choi by reverse transcription-polymerase chain reaction (RT-PCR), and its expression patterns in different organs and the apex at different developmental stages, as well as during vernalization, were analysed by quantitative real-time PCR (qPCR). The full cDNA of BrcLFY was 1353 bp in length with an open reading frame of 1260 bp encoding 419 amino acids. qPCR results showed that BrcLFY expression gradually increased during the vegetative growth stage and increased sharply at flower differentiation stage 1, with the highest expression level at flower differentiation stage 5. When comparing BrcLFY expression in different organs, we concluded that the level in young and mature leaves was significantly higher than in the apex and other tissues at flower differentiation stage 3 and visible flower bud stage and fully-bloom stage. The BrcLFY expression in germinated seeds and seedlings with five leaves was analysed during cold treatment for 0 d, 10 d and 20 d at 4 ºC and the results showed that BrcLFY gene expression rose gradually with prolonged low temperature.