Abstract
BackgroundCadmium (Cd) is a heavy metal with high toxicity that severely inhibits wheat growth and development. Cd easily accumulates in wheat kernels and enters the human food chain. Genetic variation in the resistance to Cd toxicity found in wheat genotypes emphasizes the complex response architecture. Understanding the Cd resistance mechanisms is crucial for combating Cd phytotoxicity and meeting the increasing daily food demand.ResultsUsing two wheat genotypes (Cd resistant and sensitive genotypes T207 and S276, respectively) with differing root growth responses to Cd, we conducted comparative physiological and transcriptomic analyses and exogenous application tests to evaluate Cd detoxification mechanisms. S276 accumulated more H2O2, O2−, and MDA than T207 under Cd toxicity. Catalase activity and levels of ascorbic acid (AsA) and glutathione (GSH) were greater, whereas superoxide dismutase (SOD) and peroxidase (POD) activities were lower in T207 than in S276. Transcriptomic analysis showed that the expression of RBOHA, RBOHC, and RBOHE was significantly increased under Cd toxicity, and two-thirds (22 genes) of the differentially expressed RBOH genes had higher expression levels in S276 than inT207. Cd toxicity reshaped the transcriptional profiling of the genes involving the AsA-GSH cycle, and a larger proportion (74.25%) of the corresponding differentially expressed genes showed higher expression in T207 than S276. The combined exogenous application of AsA and GSH alleviated Cd toxicity by scavenging excess ROS and coordinately promoting root length and branching, especially in S276.ConclusionsThe results indicated that the ROS homeostasis plays a key role in differential Cd resistance in wheat genotypes, and the AsA-GSH cycle fundamentally and vigorously influences wheat defense against Cd toxicity, providing insight into the physiological and transcriptional mechanisms underlying Cd detoxification.
Highlights
Cadmium (Cd) is a heavy metal with high toxicity that severely inhibits wheat growth and development
Growth performance of wheat seedlings under Cd toxicity Increasing the Cd concentration, from 0 to 100 μM, administered to the plants caused the shoot height, root length, and the biomasses of both shoots and roots to Further, we investigated the physiological responses of different wheat genotypes to Cd toxicity
The shoot height and biomass and root length and biomass were all significantly higher in T207 than S276, under Cd treatment (Fig. 2B–E). These results suggested that the wheat root, highly sensitive to Cd toxicity, could be used as an assessment of Cd resistance, and the resistance index of T207 was higher than that of S276
Summary
Cadmium (Cd) is a heavy metal with high toxicity that severely inhibits wheat growth and development. Cd accumulates in wheat kernels and enters the human food chain. Cadmium (Cd) is a heavy metal that is harmful to animals, plants, and microorganisms. Cd is highly mobile in soil; it is absorbed by plants, Zhang et al BMC Plant Biol (2021) 21:459 resulting in retarded plant growth. Cd is highly mobile in plants and contaminates agricultural products via vascular transportation [1]. It subsequently enters the human body via the food chain, and excessive intake or inhalation of Cd can damage the human immune, urinary, bone, nervous, reproductive, and other systems [2]. Cd has been listed as one of the 12 hazardous substances worldwide with environmental and food safety significance by the United Nations Environment Program since 1984 [6]
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call