Trehalose and Melatonin Interactions Alleviate Cadmium-Incited Oxidative Stress via Activating Defense Related Genes and Improve Ornamental Pepper Growth

Abstract

The mechanisms underlying the combined effects of melatonin (MT) and trehalose (Tr) on plant tolerance to cadmium (Cd) stress are scarcely explored. Hence, we assessed the ability of MT (50 mu M) and Tr (20 mM) applied individually or in combination to alleviate Cd stress in ornamental pepper by recording various growth oriented, physio-biochemical, and transcriptional aspects. Cadmium stress suppressed plant growth, physiological parameters and encouraged oxidative stress reflected by enhanced ROS burst. The combination of MT and Tr efficiently improved growth and partially reversed oxidative stress (OS) indicators in Cd-affected plants. The alleviation was likely credited to MT or Tr-encouraged antioxidant defense system in pepper, which reduced the severity of OS indicators. Overall, MT and Tr application improved Cd resistance in ornamental pepper; yet their combined application had a synergistic effect than their individual treatment. These findings revealed that MT and Tr had a positive impact on Cd tolerance in ornamental pepper.