基于SCoT标记的陕西茶树种质资源遗传多样性分析
Analysis on Genetic Diversity of Tea Germplasm in Shaanxi Based on SCoT Markers

为了明确陕西省本地群体种茶树种质资源的遗传多样性，为茶树育种提供依据。采用正交设计和单因素分析方法，对茶树SCoT-PCR体系进行优化。结果表明：20 μL最佳反应体系为Mg2+ 2.5 mmol/L，Taq 酶0.75 U，引物0.7 μmol/L，dNTPs 0.25 mmol/L，模板DNA 30 ng。利用该体系对22份陕南茶树地方品种材料进行分析，扩增条带多且清晰，22条引物共检测出241个等位位点，其中多态性位点228个，多态性比率为94.6%，位点的PIC值为0.57～0.92。供试材料之间的遗传相似系数为0.58～0.89，平均值达到0.72。基于SCoT标记的聚类与茶树叶片形态有很大的相关性。研究表明茶树SCoT 体系结果稳定，重复性好，为后续研究茶树资源遗传多样性提供技术支撑。
This study aims to unveil the genetic polymorphisms of tea in Shaanxi province,and provide basic data for tea breeding. The orthogonal design table of L16(4) and single factor experiments were designed to optimize the SCoT-PCR( start codon targeted polymorphism) system in tea. Results demonstrated that the optimal reaction system of 20 μL contained 2.5 mmol/L Mg2+,0.75 U Taq DNA polymerase,0.7 μmol/L primers,0.25 mmol/L dNTPs,30 ng DNA template. Twenty-two different tea germplasms in Shaanxi province were investigated by the optimized system,and an abundance of bands with different sizes were obtained clearly. Total of 241 fragments were generated with 22 primers in all these samples,and 94.6% of fragments showed polymorphisms. Genetic polymorphism information content of each SCoT locus was between 0.57 and 0.92. The genetic similarity coefficient was between 0.58 and 0.89,with average 0.72. Additionally,the result of dendrogram based on SCoT bands of 22 tea materials illustrated that tea genetic polymorphisms were significantly correlated with leaf morphology. In summary,the established SCoT-PCR system is stable and repeatable,which could be applied to explore genetic diversity of tea germplasm resources in further study.