Despite the worldwide consumption and high economic importance of tea, the plant (Camellia sinensis) is not well studied in molecular biology. Under the few circumstances in which the plant is studied, C. sinensis flowers, which are important for reproduction and cross-breeding, receive less emphasis than investigation of its leaves or roots. Using high-throughput Illumina RNA sequencing, we analyzed a C. sinensis floral transcriptome, and 26.9 million clean reads were assembled into 75,531 unigenes averaging 402 bp. Among them, 50,792 (67.2%) unigenes were annotated with a BLAST search against the NCBI Non-Redundant (NR) database and 10,290 (16.67%) were detected that contained one or more simple sequence repeats (SSRs). From these SSR-containing sequences, 2,439 candidate SSR markers were developed and 720 were experimentally tested, validating 431 (59.9%) novel polymorphic SSR markers for C. sinensis. Then, a consensus SSR-based linkage map was constructed that covered 1,156.9 cM with 237 SSR markers distributed in 15 linkage groups. Both transcriptome information and the genetic map of C. sinensis presented here offer a valuable foundation for molecular biology investigations such as functional gene isolation, quantitative trait loci mapping, and marker-assisted selection breeding in this important species.

No abstract

No abstract

The genetic diversity among 30 tea cultivars in Sichuan of China was investigated by PCR-RFLP analysis of cp DNA. 7 sets of chloroplast primers could produce one or more than one distinct bands by direct electrophoresis in 2% agrose gels. After the amplified products were digested by 10 restriction enzymes, a total of 135 bands were detected, among which 98 bands (72.59%) were polymorphic. The cpDNA PCR-RFLP based genetic distance (GD) among 30 tea accessions ranged from 0 to 0.071, with the mean of 0.049.

ABSTRACT. Genetic maps are essential tools for quantitative trait locus analysis and marker-assisted selection breeding. In order to select parents that are highly heterozygous for genetic mapping, the heterozygosity (H S ) of 24 tea cultivars (Camellia sinensis) was analyzed with 72 simple sequence repeat markers. In total, 359 alleles were obtained with an average of 4.99 per marker. The H S varied greatly from 37.5 to 71.0% with an average of 51.3%. On average, tea cultivars from Fujian Province showed a higher level of heterozygosity (59.8%) than those from Zhejiang (48.5%) and Yunnan (44.5%), and the 12 national tea cultivars were generally more heterozygous than the 12 provincial cultivars. Unweighted pair-group analysis using the arithmetic average grouping divided the 24 cultivars into 2 groups that are consistent with the morphological classification. All dual combinations of the 24 cultivars were studied to calculate the percentage of mappable markers when using pseudo-testcross mapping strategy, and results showed that this value also varied greatly from 51.4 to 90.3%. The genetic relationships and H S differences among different cultivars were discussed, and tea cultivars with high H S were recommended as cross parents for genetic mapping programs.