Wang Juan, Du Junjie, Mu Xiaopeng, Wang Pengfei
Department of Pomology, College of Horticulture, Shanxi Agricultural University, Taigu, China.
Institute of Pomology, Shanxi Academy of Agricultural Sciences, Taiyuan, China.
PLoS One. 2017 Oct 16;12(10):e0186650. doi: 10.1371/journal.pone.0186650. eCollection 2017.
Sucrose is crucial to the growth and development of plants, and sucrose phosphate synthase (SPS) plays a key role in sucrose synthesis. To understand the genetic and molecular mechanisms of sucrose synthesis in Cerasus humilis, ChSPS1, a homologue of SPS, was cloned using RT-PCR. Sequence analysis showed that the open reading frame (ORF) sequence of ChSPS1 is 3174 bp in length, encoding a predicted protein of 1057 amino acids. The predicted protein showed a high degree of sequence identity with SPS homologues from other species. Real-time RT-PCR analysis showed that ChSPS1 mRNA was detected in all tissues and the transcription level was the highest in mature fruit. There is a significant positive correlation between expression of ChSPS1 and sucrose content. Prokaryotic expression of ChSPS1 indicated that ChSPS1 protein was expressed in E. coli and it had the SPS activity. Overexpression of ChSPS1 in tobacco led to upregulation of enzyme activity and increased sucrose contents in transgenic plants. Real-time RT-PCR analysis showed that the expression of ChSPS1 in transgenic tobacco was significantly higher than in wild type plants. These results suggested that ChSPS1 plays an important role in sucrose synthesis in Cerasus humilis.
蔗糖对植物的生长发育至关重要，蔗糖磷酸合酶（SPS）在蔗糖合成中起关键作用。为了解野生樱桃李中蔗糖合成的遗传和分子机制，采用RT-PCR技术克隆了SPS的同源基因ChSPS1。序列分析表明，ChSPS1的开放阅读框（ORF）序列长度为3174 bp，编码一个预测的1057个氨基酸的蛋白质。预测的蛋白质与其他物种的SPS同源物具有高度的序列同一性。实时RT-PCR分析表明，ChSPS1 mRNA在所有组织中均有检测到，且在成熟果实中的转录水平最高。ChSPS1的表达与蔗糖含量之间存在显著正相关。ChSPS1的原核表达表明ChSPS1蛋白在大肠杆菌中表达且具有SPS活性。ChSPS1在烟草中的过表达导致转基因植物中酶活性上调和蔗糖含量增加。实时RT-PCR分析表明，ChSPS1在转基因烟草中的表达显著高于野生型植物。这些结果表明，ChSPS1在野生樱桃李的蔗糖合成中起重要作用。
