普通白菜1，5- 二磷酸核酮糖羧化/ 加氧酶小亚基基因BcrbcS 的克隆及表达分析

利用RACE 技术，从普通白菜抗霜霉病品种苏州青叶片克隆到1，5- 二磷酸核酮糖羧化/ 加氧酶小亚基（ribulose-1， 5-bisphosphate carboxylase/oxygenase small subunit，BcrbcS）基因的全长cDNA 序列。采用qRT-PCR 分析该基因在普通白菜不 同组织的表达模式。利用SDS-PAGE 技术分析了该基因的原核表达特征。序列分析结果表明，BcrbcS 基因的cDNA 序列全 长为733 bp，其中开放阅读框长度为543 bp，共编码181 个氨基酸，分子质量为20.3×10³ Da，理论等电点为8.23。氨基酸 同源系统进化分析表明，普通白菜BcrbcS 基因与同科植物的进化关系相近。实时定量分析结果表明，BcrbcS 基因在普通白 菜叶中表达最强；在SA 和NaCl 处理下，BcrbcS 基因表达量均在处理24 h 后达到峰值。原核表达载体经IPTG 诱导表达出分 子质量约为20×10³ Da 的融合蛋白。

Cloning and Expression Analysis of Ribulose-1，5-bisphosphate carboxylase/oxygenase Small Subunit Gene BcrbcS in Pakchoi

The full-length cDNA sequence of ribulose-1，5-bisphosphate carboxylase/oxygenase small subunit （BcrbcS）gene was cloned from the leaves of pakchoi cultivar‘Suzhouqing’with resistance to downy mildew by RACE technique．This paper analyzed the expression pattern of this gene under different tissues by qRT-PCR and also prokaryotic expression characteristics of this gene by SDS-PAGE technology．Results of sequence analysis showed that the full-length cDNA of BcrbcS gene was 733 bp，among which the length of open reading frame was 543 bp．The total encodings were 181 amino acids．The molecular mass was 20.3×10³ Da，and theoretical isoelectric point was 8.23．The phylogenetic analysis of amino acid homology showed that the pakchoi BcrbcS gene had similar evolutionary relationship with the other plants in the same family．Results of quantitative real-time analysis showed that the expression of BcrbcS gene was the strongest in pakchoi leaves．The expression of BcrbcS gene in pakchoi peaked at 24 hours after infection with SA and NaCl．Prokaryotic expression vector was induced by IPTG to express a fusion protein with a molecular weight of about 20×10³ Da．