Establishment of in Vitro Hapliids of Tea (Camellia SPP) and Their Potential for the Production of Secondary Metabolites
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The tea plant is a tropical, evergreen plant of the family Theaceae and genus Camellia. It is one of the most economically important beverage crops in the world. Chinese were the first to use tea as medicinal drink, later as beverage and have been doing so far for more than 3000 years. The original home or primary centre of origin of tea was South-East Asia. The cultivated taxa of tea comprise three main types, which are mainly differentiated on the basis of their leaf size. Assam type has the biggest leaf size while China type has the smallest. The Cambod type has leaf in between Assam and China types. Tea plant is a highly cross pollinated and genetically complex species. The genus Camellia includes more than 325 species which indicates genetic instability and high out-breeding nature of the genus. There are 600 cultivated varieties worldwide with unique traits, such as high caffeine content, drought tolerance, blister blight disease tolerant etc. In spite of having valued properties, improvement of tea by conventional methods is very laborious and time consuming and owing to its highly heterozygous nature and long reproductive cycle. In this context, it is noteworthy that, studies utilizing gametophytic cells are in infancy, in this tree species. In vitro haploid production from gametophytic cells enables the establishment of completely homozygous lines in a shortened time frame compared to conventional methods and has many potential applications in plant improvement to establish inbred lines rapidly and to observe recessive traits. Therefore, the aim of the present study was to establish in vitro androgenic lines of tea from anthers. Androgenic haploids were produced by anthers, cultured at early-to-late uninucleate stage of pollen. Haploid development occurred via callusing of microspores. TV21 and TV19 cultivars were regenerated and developed to haploid plants. Further, the androgenic lines were checked for the production of medicinally important compounds, such as (+)-Catechin, (-)-Epicatechin, (-)-Epigallocatechin gallate, Caffeine and Theophylline. These compounds are observed to be present in maximum amount in young leaves of parent plants, followed by in vitro embryos and the least in calli. The presence of compounds has been confirmed by chromatographic and spectroscopic techniques. Antioxidant activity assays of in vitro androgenic cultures were also investigated and found that hot water extract (80जC for 20 min.) shows maximum activity. Batch kinetics.
Supervisor: Rakhi Chaturvedi
BIOSCIENCES AND BIOENGINEERING