Cloning and expression analysis of SPL8 homolog from pak choi (Brassica rapa subsp. chinensis)

Abstract

SQUAMOSA PROMOTER-BINDING PROTEIN-LIKE (SPL) transcription factor genes are functionally diverse; they control a number of fundamental aspects of plant growth and development, including vegetative phase change, flowering time, branching and leaf initiation rate. In our previous study, expression profiling showed that Bra033221, a transcript-derived fragment of an AtSPL8 ortholog, was up-regulated at flower bud differentiation stage 5. This result suggested that Bra033221 has a function similar to that of AtSPL8. In the present study, BrcSPL8, an AtSPL8 homolog, was cloned from pak choi (Brassica rapa subsp. chinensis) based on Bra033221 using reverse transcription-polymerase chain reaction (RT-PCR). The full-length cDNA was 1117 bp and contained a complete open reading frame (ORF) of 987 bp; this ORF encoded a predicted protein with 328 amino acid residues, a calculated molecular mass of 36.55 kDa and an isoelectric point of 8.85. BrcSPL8 was expressed in all analysed apices. Its expression levels before flower differentiation stage 1 were low and almost invariable, and the highest expression was detected in the apex at flower differentiation stage 5, suggesting that BrcSPL8 has a role during flower development in pak choi.

Keywords

• Brassica rapa subsp. chinensis
• BrcSPL8
• cloning
• expression