SSR-based molecular diagnosis for Taiwan tea cultivars and its application in identifying cultivar composition of the processed tea

Taiwan specialty teas are produced with distinct manufacturing processes from specific cultivars of tea plants in Camellia. Due to the widespread transplantation of Taiwan tea cultivars and active international trading of tea materials, an accurate and reliable method to identify tea cultivars at the border is vital to protect the image of premium Taiwan specialty teas. In this study, we introduced the Taiwan Tea Variety Identification (TTVID) kit, a capillary electrophoresis-based multiplex PCR assay consisting of 12 simple sequence repeat (SSR) markers. A database composing these 12 SSR loci genotypes in 144 cultivars was established for marker assessment and molecular diagnosis. The power of discrimination on a locus ranged from 0.7894 to 0.966 and the combined match probability of 12 SSR loci was 5.34e-14. Cultivar pairwise comparison among 144 accessions showed that over 90.6% of the pairs had differential genotypes on at least 10 of 12 SSR loci. Further assessment showed that the TTVID kit could unambiguously recognize the cultivars mixed in the loose-leaf teas processed with various degrees of fermentation and roasting. Our results suggested that this TTVID kit effectively identified cultivar composition in loose-leaf tea and is helpful for border control in preventing adulteration and fraud in the Taiwan tea market.