Study of Chloroplast DNA diversity and Genetic Relationships of some Tea Genotypes

The herbal tea [Camellia sinensis (L.) O.Kuntze)] is a non-alcoholic beverage with many medicinal properties that has entered Iran in the last century and cultivated in the northern region. Understanding the genetic diversity of plants for breeding programs and the protection of germplasm is very important so that it can be stated that the collection and evaluation of domestic and foreign germplasm reserves is the most important stage in plant breeding programs. Many studies have been done on the nucleus genome of this plant, but the investigation of the organelles genome relationships in this plant is very limited. For the first time in this research, we have tried to investigate the diversity of this germplasm in Iran by using the genome of chloroplasts.

In this research, 35 tea-plant samples from six populations (east tea cultivation district (Nashtarood), central tea cultivation district (Lahijan), west tea cultivation district (Fashalem), imported genotypes from Georgia, imported clones from Japan, and imported clones from Sri Lanka) in three collections of the tea institute were studied. At first sampling of young and fully developed leaves was performed and the DNA genomes were extracted. By using five pairs of specific primers for the chloroplast genome (DT, LF, HK, SC and rbcl) and four restriction enzymes (BglII, HinfI, AluI and PstI) with Polymerase Chain Reaction- Restriction Fragment Length Polymorphism (PCR- RFLP) method, the variety in the chloroplast genome of these plants was investigated. NTSYS and POPGENE were used for cluster and population analysis.

In this study, about 6980bp of the tea chloroplast genome was amplified in polymerase chain reaction and examined by restriction enzymes. Of the 20 primer/ enzyme combinations, four combinations (DT/ HinfI, DT/ AluI, LF/ PstI and HK/ HinfI) were shown polymorphic pattern and these four compounds put samples into seven haplotypic groups (H1, H2, H3, H4, H5, H6 and H7). All these grouping were created due to the occurrence of insertion-deletion mutations in the range of 10-40bp. Mean of genetic variation within (HS), Total (HT) and degree of genetic differentiations (GST) were 0.25, 0.46 and 0.45, respectively.

The results of investigation of 35 tea samples showed that there was no cognitive genetic structure between the different sample regions. These results also confirmed the possibility of utilization Polymerase Chain Reaction- Restriction Fragment Length Polymorphism (PCR- RFLP) technique to investigation of genetic diversity and identify genotypes and varieties of tea.