Exogenous Melatonin Enhances Cold, Salt and Drought Stress Tolerance by Improving Antioxidant Defense in Tea Plant (Camellia sinensis (L.) O. Kuntze).

Jiahao Li,Yiqing Yang,Xuan Chen,Kang Sun,Xinghui Li,Yi Chen

doi:10.3390/molecules24091826

Jiahao Li, Yiqing Yang + Show 4 more

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https://doi.org/10.3390/molecules24091826

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Abstract

Melatonin is a biological hormone that plays crucial roles in stress tolerance. In this study, we investigated the effect of exogenous melatonin on abiotic stress in the tea plant. Under cold, salt and drought stress, increasing malondialdehyde levels and decreasing maximum photochemical efficiency of PSII were observed in tea leaves. Meanwhile, the levels of reactive oxygen species (ROS) increased significantly under abiotic stress. Interestingly, pretreatment with melatonin on leaves alleviated ROS burst, decreased malondialdehyde levels and maintain high photosynthetic efficiency. Moreover, 100 μM melatonin-pretreated tea plants showed high levels of glutathione and ascorbic acid and increased the activities of superoxide dismutase, peroxidase, catalase and ascorbate peroxidase under abiotic stress. Notably, melatonin treatments can positively up-regulate the genes (CsSOD, CsPOD, CsCAT and CsAPX) expression of antioxidant enzyme biosynthesis. Taken together, our results confirmed that melatonin protects tea plants against abiotic stress-induced damages through detoxifying ROS and regulating antioxidant systems.

Highlights

IntroductionKuntze) plant is an important economic crop that has been planted in China for nearly 2000 years [1]
The results show that exogenous application of melatonin stimulated melatonin might alleviate abiotic stress-triggered reactive oxygen species (ROS) accumulation and cell membrane damage in ROS-related antioxidant enzymes activities in tea plants under abiotic stress
Abiotic stresses viamelatonin differenthas mechanisms resultfocus in a decrease resistance andmarkedly crop yield,inhibit among plant these, growth exogenous emerged asand a research in plant science

Summary

Introduction

Kuntze) plant is an important economic crop that has been planted in China for nearly 2000 years [1]. As a perennial evergreen woody crop, tea plants are often subjected to various abiotic stresses such as drought, high salt and low temperature during the growth process [2], which are the main environmental factors that affect the geographical distribution of tea plant and limit the yield of tea [3]. Effective ways to improve the abiotic stress tolerance on tea plants are urgently needed. Malondialdehyde (MDA) content is generally considered as an indicator of membrane structural integrity. The level of MDA content has increased significantly under abiotic stress, resulting in decreased membrane fluidity and destroyed ion homeostasis on plants [7]. Photosynthesis, the most important physicochemical process in higher plants, is very sensitive to abiotic stress [8,9]

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