Glycinebetaine facilitates the photosynthesis of albino tea under low temperature by regulating related gene methylation

The frequent occurrence of adverse weather conditions in early spring caused by global climate change has seriously restricted the physiological metabolism and growth of plants in recent years. As a low temperature sensitive albino tea cultivar, white leaf No. 1 (WL-1) has been seriously affected. Regulation of DNA methylation (an epigenetic regulator) due to global climate change by glycinebetaine (GB, a bioactive methyl donor) has been often observed in animals/humans, but little is known about whether it is linked to gene methylation priming responses of plants to low temperature. Herein, the effects of foliar application of GB on photosynthesis, photosynthetic pigment synthesis and related genes methylation of WL-1 functional leaves under low temperature were investigated. Results showed that the transpiration efficiency and chlorophyll contents of WL-1 functional leaves under low temperature condition were significantly improved by the application of GB (P < 0.05), and the net photosynthetic rate was increased by 45.3%. In addition, the application of GB promoted the methylation of most methyltransferase and demethylase genes, PSⅡ component genes and some chlorophyll synthesis genes in WL-1 functional leaves under low temperature. It was verified that the changes of photosynthetic parameters and chlorophyll content may be correlative to related gene methylation. Together, present study suggests important roles of GB in facilitating photosynthesis of albino tea functional leaves under low temperature by regulating related gene methylation.