Shoot Epicatechin and Epigallocatechin Contents Respond to Water Stress in Tea [Camellia sinensis(L.) O. Kuntze]

Abstract

An experiment was conducted to determine the association of tea catechins to water stress in tea, with the objective of determining their suitability as indicators for predicting drought tolerance in tea (Camellia sinensis). The study consisted of six tea clones (BBK 35, TRFK 6/8, TRFK 76/1, TRFK 395/2, TRFK 31/30, and TRFK 311/287) and four levels of soil water content (38, 30, 22, and 14% v/v), which were arranged in a complete randomized design and replicated 3 times. The treatments were maintained for a period of 12 weeks. Tea shoots were sampled for catechin analysis during the 6th week of water treatment, in which fresh shoots with two leaves and a bud were plucked and steamed for 2 min, and dried at 70 C to constant weight. Subsequently, the samples were ground and analyzed for catechins using an HPLC system. The total catechins showed significant correlation with shoot growth (r ¼ 0:65, P ¼ 0:006), soil water content (r ¼ 0:54, P ¼ 0:0066), and water stress index (r ¼ 0:67, P ¼ 0:0004). The epicatechin (EC) correlated with shoot growth (r ¼ 0:58, P ¼ 0:0032), soil water content (r ¼ 0:62, P ¼ 0:0014), and water stress index (r ¼ 0:63, P ¼ 0:0010). Similarly, epigallocatechin (EGC) correlated with shoot growth (r ¼ 0:65, P ¼ 0:0006), soil water content (r ¼ 0:50, P ¼ 0:0133), and water stress index (r ¼ 0:60, P ¼ 0:0021). However, epigallocatechin gallate (EGCg) and epicatechin gallate (ECG) showed no significant response to changes in soil water content. The shoot contents of EC and EGC in the six clones showed varied responses, with a distinct pattern in the water-stress tolerant clones (TRFK 6/8 and TRFK 31/30). The results suggest a potential use for EC and EGC as indicators in predicting drought tolerance in tea.Key words: catechins; drought stress; flavan-3-ol; free radicals Plants are known to accumulate organic osmolytes such as proline, glycine betaine, non-reducing sugars, and polyols 1,2) in response to stress factors. Though these organic compounds are species-specific their role is not clearly defined, but it is generally accepted that they contribute to ameliorating stress in plants. [2][3][4] Most stress-related organic compounds are secondary plant metabolites, and tea (Camellia sinensis) contains large amounts of polyphenols, mainly catechins, that belong to the flavan-3-ol class. Flavonoids play a key role in quality determination in black tea, 5) and in fruits, 6) but their role as indicators of desiccation tolerance in tea has not been explored. The precursors of most flavonoids are malonyl-CoA, derived from carbohydrate metabolism and p-coumaroyl-CoA, from the phenylpropanoid pathway. 7-9) Phenylpropanoids, which include flavonoids, isoflavonoids, and stilbenes, are derived from deamination of phenylalanine by phenylalanine ammonialyase (PAL). Flavonoid biosynthesis is dependent on structural and regulatory genes; structural genes encode enzymes catalyzing the biosynthesis, while regulatory genes control the expression of the genes. 8,[10][11][12][13][14] This implies that the availab...

Genome-enabled prediction models for black tea (Camellia sisnesnsis) quality and drought tolerance traits

“…The putatively annotated proteins for catechin trait were those associated with phenylalanine, tyrosine and tryptophan biosynthesis and carbon fixation, which are products for shikimate pathway (Maeda;Dudareva, 2012) and abiotic stress response (stomatal closure). Hence, it was in agreement with this study since previous reports have shown that catechins play a role as indicators of desiccation tolerance in tea plants (Cheruiyot et al , 2008). Aminotransferases have been shown to play a major role in a variety of metabolic pathways, including, amino acid biosynthesis and photorespiration.…”

Changes in Polyphenol Levels in Satsuma (Citrus unshiu) Leaves in Response to Asian Citrus Psyllid Infestation and Water Stress

“…The results presented in this study indicate a general trend of increase in levels of polyphenols in response to both biotic and abiotic stresses. These results are in line with the reports that indicate that plants produce a wide range of secondary metabolites such as polyphenols during their normal growth and that these levels often change in response to stresses [26][27][28][29]. These responses may be elicited by interactions with microbes, insect pests, the environment, or the farm management practices.…”

ABIOTIC STRESS RESPONSES IN TEA [<i>Camellia sinensis</i> L (O) Kuntze]: AN OVERVIEW

“…Green tea is comparatively healthier than black and Oolong tea. Literature also suggests polyphenols as potential indicators of drought tolerance in Camellia sinensis (Cheruiyot et al, 2007) because of variation of shoot epicatechin and epigallocatechin contents in response to water stress (Cheruiyot et al, 2008). Tea plants are grown in a wide range of latitudes in the world ranging from 45 N (Russia) to 30 S (South Africa) and longitude from 150 E (New Guinea) to 60 W(Argentina).…”

“…Growth and productivity of tea plants largely depends on their capacity to adapt to abiotic stress, namely temperature, drought, metal, and nutritional disturbances. Although the effects of some individual environmental factors on the tea plant are well documented (Handique and Manivel, 1990;Chakraborty et al, 2002;Panda et al, 2003;Upadhyaya and Panda, 2004a;Jeyaramraja et al, 2005;Sharma and Kumar, 2005;Cheruiyot et al, 2007;Cheruiyot et al, 2008;Upadhyaya et al, 2008;Yadavand Mohanpuria, 2009;Upadhyaya et al, 2011;Upadhyaya et al, 2012;Das et al, 2012;Gupta et al, 2012), the effects of interacting abiotic factors remain poorly investigated.Therefore, the objective of this review is to highlight the effects of drought, heavy metal stress, and their interaction on growth, water relationships, nutrient status, and antioxidative responses during abiotic stress and its recovery in the tea plant.…”

“…Reduced absorption of inorganic nutrients results from interference with nutrient uptake, unloading mechanisms, and reduced transpiration flow (Gunes et al, 2007 O 2 ) within the cell, particularly within the chloroplasts of water stressed leaves. Such ROS generation leads to lipid peroxidation, protein degradation, and enzyme inactivation and affects nucleic acid and almost every component of cell, leading to cell death (Panda, 2002;Upadhyaya and Panda, 2004b;Jeyaramaraja et al, 2005;Cheruiyot et al, 2007;Cheruiyot et al, 2008;Upadhyaya et al, 2008).…”