Glycinebetaine mitigates drought stress-induced oxidative damage in pears

Glycinebetaine (GB) is an osmoprotectant found in plants under environmental stresses that incorporates drought and is associated with drought tolerance in several plants, such as the woody pear. However, how GB improves drought tolerance in pears remains unclear. In the current study, we explored the mechanism by which GB enhances drought tolerance of whole pear plants (Pyrus bretschneideri Redh. cv. Suli) supplied with exogenous GB. The results showed that on the sixth day after withholding water, levels of O-2 center dot(-), H2O2, malonalde-hyde (MDA) and electrolyte leakage in the leaves were substantially increased by 143%, 38%, 134% and 155%, respectively. Exogenous GB treatment was substantially reduced O-2 center dot(-), H2O2, MDA and electrolyte leakage (38%, 24%, 38% and 36%, respectively) in drought-stressed leaves. Furthermore, exogenous GB induced considerably higher antioxidant enzyme activity in dry-stressed leaves than drought-stressed treatment alone on the sixth day after withholding water, such as superoxide dismutase (SOD) (201%) and peroxidase (POD) (127%). In addition, these GB-induced phenomena led to increased endogenous GB levels in the leaves of the GB 100 + drought and GB 500 + drought treatment groups by 30% and 78%, respectively, compared to drought treatment alone. The findings obtained were confirmed by the results of the disconnected leaf tests, in which GB contributed to a substantial increase in SOD activity and parallel dose- and time-based decreases in MDA levels. These results demonstrate that GB-conferred drought resistance in pears may be due in part to minimizing symptoms of oxidative harm incurred in response to drought by the activities of antioxidants and by reducing the build-up of ROS and lipid peroxidation.

Automated summary

Glycinebetaine (GB) is an osmoprotectant found in plants that plays a role in response to environmental stresses such as drought. Exogenous GB has been shown to enhance drought tolerance in pear trees by reducing oxidative damage, increasing antioxidant enzyme activity, and reducing levels of oxidative substances and electrolyte leakage in leaves. This study suggests that GB-mediated drought resistance in pears may be attributed to its antioxidant activities and reduction of reactive oxygen species (ROS) and lipid peroxidation.