Inuloxin A Inhibits Seedling Growth and Affects Redox System of Lycopersicon esculentum Mill. and Lepidium sativum L.

Abstract

Allelochemicals are considered an environment-friendly and promising alternative for weed management, although much effort is still needed for understanding their mode of action and then promoting their use in plant allelopathy management practices. Here, we report that Inuloxin A (InA), an allelochemical isolated from Dittrichia viscosa, inhibited root elongation and growth of seedlings of Lycopersicon esculentum and Lepidium sativum at the highest concentrations tested. InA-induced antioxidant responses in the seedlings were investigated by analysing the contents of glutathione (GSH) and ascorbate (ASC), and their oxidized forms, dehydroascorbate (DHA), and glutathione disulphide (GSSG), as well as the redox state of thiol-containing proteins. An increase in ASC, DHA, and GSH levels at high concentrations of InA, after 3 and 6 days, were observed. Moreover, the ASC/DHA + ASC and GSH/GSSG + GSH ratios showed a shift towards the oxidized form. Our study provides the first insight into how the cell redox system responds and adapts to InA phytotoxicity, providing a framework for further molecular studies.

Multiple Physiological and Biochemical Functions of Ascorbic Acid in Plant Growth, Development, and Abiotic Stress Response

“…Plant chilling injury (CI) is caused by a series of events, starting with a slight increase in cell membrane viscosity, followed by an increase in ROS leading to further membrane dysfunction, protein oxidation, inhibition of enzymatic activity, and DNA and RNA damage [85]. Importantly, changes in the redox state of plants lead to changes in thiol protein (SH-group) patterns, which in turn generate metabolic perturbations [86]. In both Lycopersicon esculentum and Lepidium sativum treated with Inuloxin A (InA), the fluorescence of the SH-group, labeled with monobromo-bimane (mBBr), is lower than that of the control [86].…”

“…Importantly, changes in the redox state of plants lead to changes in thiol protein (SH-group) patterns, which in turn generate metabolic perturbations [86]. In both Lycopersicon esculentum and Lepidium sativum treated with Inuloxin A (InA), the fluorescence of the SH-group, labeled with monobromo-bimane (mBBr), is lower than that of the control [86].…”

“…The high correlation between CsAPX1 and CsGLB1 suggests that cytoplasmic AsA could modulate life activities by cooperating with nitrogen regulatory proteins in the tea plant under nitrogen deficiency [91]. The AsA/DHA and GSH/GSSG ratios exhibit a shift towards the oxidized form under an allelochemical InA stress, offering insight into the response pattern of the plant cell redox system [86].…”