Genetic diversity within cultivated teas based on nucleotide sequence comparison of ribosomal RNA maturase in chloroplast DNA

Nucleotide sequences of ribosomal RNA maturase (matK) regions in chloroplast (cp) DNA were determined to assess genetic diversity within cultivated teas. One hundred-eighteen cultivated teas from India, Bangladesh, Myanmar, Thailand, Laos, Vietnam, China and Japan were analyzed. The 1,230 aligned nucleotide sequences of the matK DNA of the cultivated teas showed 13 variations. These variations in the matK defined 10 different types (CJ, AA, AB, AC, AD, AE, IC, IM, TM and TV). By nucleotide alignment analysis, the matK nucleotide sequences in the samples from Japan and eastern China and from tea estates in India and Bangladesh were divided into CJ and AA types. On the other hand, the matK in the teas of Yunnan in China and southeast Asian countries shared 9 types (AA, AB, AC, AD, AE, IC, IM, TM and TV). The matK sequences of southeastern cultivars were fragmented into smaller population clusters as compared to the eastern samples. In addition, these matK types were classified into three groups. The CJ, AA and AB types were placed in the group Camellia sinensis (var. sinensis and var. assamica). The AC, IC, IM, TM and TV types had strong affinity to C. taliensis and C. irrawadiensis. AE and AD types with 6-base insertions belonged to a third group. Results of the matK nucleotide sequence analysis indicated that the cultivated teas of India, Bangladesh, eastern China and Japan belonged to the group of C. sinensis. The cultivated teas in the estates of Southeast Asia region also belonged to C. sinensis. However, the native cultivars in Myanmar and southern China had a genetic similarity to C. taliensis and C. irrawadiensis. The native cultivars of Thailand and Vietnam will be associated with morphologically close taxa. In this study, we demonstrated that members of C. irrawadiensis and C. taliensis are popular cultivars found widely in the southeastern Asia. Tea cultivars of the AC, AD, AE, IC, IM, TM and TV types merit to be conserved for use as sources of desirable genes.