Abstract:

Based on a cDNA library constructed from Chimonanthus praecox flowers and EST analysis, a new heat shock proteins(HSPs) gene was cloned by randomly cloning and sequencing, named as CpHSP1 (GenBank accession No. HQ894379). The full length of CpHSP1 cDNA sequence was 790 bp, with an open reading frame (ORF) of 477 bp encoding a putative polypeptide of 158 amino acid residues. Sequence alignments and phylogenetic analysis revealed CpHSP1 to be a cytosolic class Ⅰ smHSP(small HSPs) which contained consensus Ⅰ and Ⅱ of ACD(α-crystallin domain)in the carboxyl-terminal (C-terminal) domain,and a conserved region specific for cytosolic class Ⅰ smHSPs in the amino-terminal (N-terminal) domain. According to expression studies by real-time quantitative PCR, CpHSP1 was constitutively expressed in vegetative and reproductive organs at different developmental stages under normal conditions, and it was expressed highest in stems than other organs. CpHSP1 transcripts were detected during blooming and more abundant in petals than that in stamens and pistils, whereas CpHSP1 was hardly expressed in non-stressed leaf tissue but strongly induced under various abiotic stresses such as high temperature, low temperature, salinity, ABA and heavy metal. All these transcriptional expression analysis results suggested that CpHSP1 may play a significant role in plant development and abiotic stress responses.

Key words: Chimonanthus praecox, heat shock proteins(HSPs), cloning, gene expression