茶树EST-SSR的信息分析与标记建立

在1589条茶树EST中,共发掘出了281个EST-SSR,分布于246条EST中,出现频率是17.68%,平均长度为33.06βbp,平均分布频率是1/2.61βkb。在茶树EST-SSR中,二核苷酸重复是主要的重复类型,出现最多的重复基元类型是AG/CT重复。设计了19对SSR引物,在对引物、dNTP、MgCl₂的浓度及退火温度等参数进行测试后,建立了合适的PCR反应体系。以衍生绝大多数EST-SSR的龙井43βDNA为模板,对引物进行了筛选,有16对引物显示扩增,可用率为84.2%; 进一步在10个茶树品种中进行多态性测试,显现出多态性的引物占可扩增引物的62.5%。本文研究结果证明了根据茶树EST建立SSR标记是有效、可行的。

Data Mining for SSRs in ESTs and Development of EST-SSR Marker in Tea Plant (Camellia sinensis)

Totally 281 SSRs distributed in 246 ESTs were mined out,accounting for 17.68% of 1589 ESTs updated in tea.The average length of tea plant EST-SSRs searched out is 33.06 bp and the average distance of distribution is 1/2.16 kb.The dinucleotide repeat is the dominant type with repeat motif AG/CT being the most common.19 primer pairs for EST-SSRs were designed.After testing on the annealing temperature and the concentration of primers,dNTP and MgCl2,a suitable PCR system was established.Under the condition of reaction system developed,the primers designed were screened against genomic DNA of Longjing 43 from which most EST-SSRs were derived,and 16 primer pairs showed the amplification,accounting for 82.4% of total primers.Then the primers showing amplification were subjected to PCR for DNAs from 10 tea plant cultivars and 10 primer sets showed polymorphisms,accounting for 62.5% of primers available.Results prove that it is an effective and feasible approach to develop SSR markers based on ESTs in tea.