Physiological mechanisms and genetic factors of the tea plant Camellia sinensis (L.) Kuntze response to drought

The main constraint in the tea plants growth in the world is drought, which reduces the productivity of plantations by 15-45 % (R.M. Bhagat et al., 2010; R.D. Baruah et al., 2012). In this regard, physiological (M. Mukhopadhyay et al., 2014; T.K. Maritim et al., 2015) and molecular mechanisms (W.D. Wang et al, 2016; Y. Guo et al., 2017) drought tolerance of tea plants are a matter of great interest. The purpose of this review is to summarize the international experience of phenotyping and genotyping of tea drought response to create a comprehensive picture of the plant response to osmotic stress and to understand the reproducibility of response mechanisms in different climatic regions. During drought stress the main signaling role is played by abscisic, jasmonic and salicylic acids, as well as ethylene (S.C. Liu et al., 2016), the metabolic pathway of which includes cascades of physiological changes and involves response genes (T. Umezawa et al., 2010). It was reported that tea plants had increased expression of genes encoding cytokinin biosynthesis enzymes (trans-zeatin and cis-zeatin and isopentyniladine) under drought, and during recovery its expression decreased...