Journal Article

Comparative physiological and transcriptomic analyses reveal ascorbate and glutathione coregulation of cadmium toxicity resistance in wheat genotypes

Jie, Yaqi, Huang, Jinyong, Yue, Caipeng, Zhao, Yongsheng, Shen, Dandan, Xiao, Jingui, Hua, Yingpeng, Zhang, Yifan, Zhou, Ting, Zhang, Tao

2021

Overview

Background Cadmium (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. Results Using 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 H 2 O 2 , O 2 − , 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. Conclusions The 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.

• Publisher: BioMed Central,BioMed Central Ltd,Springer Nature B.V,BMC
• Subject: Adaptation, Physiological - genetics / Agricultural research / Agriculture / Antioxidants / AsA-GSH cycle / Ascorbic acid / Ascorbic Acid - genetics / Ascorbic Acid - metabolism / Biomass / Biomedical and Life Sciences / Cadmium / Cadmium - toxicity / Catalase / Cd resistance / Detoxification / Food / Food chains / Gene expression / gene expression regulation / Gene Expression Regulation, Plant / Genes / Genetic aspects / Genetic diversity / Genetic Variation / Genotype / Genotype & phenotype / Genotypes / Genotypic diversity / Glutathione / Glutathione - genetics / Glutathione - metabolism / growth and development / Growth and Development - drug effects / Hardiness / Heavy metals / Homeostasis / human food chain / Hydrogen peroxide / Life Sciences / Lipid peroxidation / Oxidative stress / Peroxidase / Physiological aspects / Physiology / Phytotoxicity / Plant growth / Plant Sciences / Plants / root growth / ROS / Scavenging / Superoxide dismutase / Toxicity / Transcription / transcription (genetics) / Transcriptome - drug effects / transcriptomics / Tree Biology / Triticum - genetics / Triticum - growth & development / Triticum - metabolism / Vitamin C / Wheat