Morphological and Physiological Indicators and Transcriptome Analyses Reveal the Mechanism of Selenium Multilevel Mitigation of Cadmium Damage in Brassica juncea

Abstract

Cadmium (Cd) is a common agricultural soil pollutant, which does serious harm to the environment and the human body. In this study, Brassica juncea was treated with different concentrations of CdCl2 and Na2SeO3. Then, physiological indexes and transcriptome were measured to reveal the mechanisms by which Se reduces the inhibition and toxicity of Cd in B. juncea. The results showed that Se alleviated the inhibitive Cd effects on seedling biomass, root length, and chlorophyll, and promoted the adsorption of Cd by pectin and lignin in the root cell wall (CW). Se also alleviated the oxidative stress induced by Cd, and reduced the content of MDA in cells. As a result, SeCys and SeMet alleviated the transport of Cd to the shoots. Transcriptome data showed that the bivalent cation transporter MPP and ABCC subfamily participated in the separation of Cd in vacuoles, CAL1 was related to the chelation of Cd in the cytoplasm of cells, and ZIP transporter 4 reduced the transport of Cd to the shoots. These results indicated that Se alleviated the damage of Cd in plants and decreased its transport to the shoots by improving the antioxidant system, enhancing the ability of the CW to adsorb Cd, reducing the activity of Cd transporters, and chelating Cd.

Stenotrophomonas strain CD2 reduces cadmium accumulation in Brassica rapa L.

“…According to the GO enrichment analysis, inoculation with "CD2" affected the expression of genes related to cell wall biosynthesis in roots and membranes (plasma, thylakoid, chloroplast, and photosynthetic) in aerial tissues. Similar results have been reported in Cd-stressed maize and mustard (Brassica juncea) (Peng et al, 2015;Li et al, 2023). Studies suggest that the biosynthesis of cutin, suberine, wax, and phenylpropanoid confers abiotic stress resistance in plants.…”

Molecular Mechanisms of the Effects of Sodium Selenite on the Growth, Nutritional Quality, and Species of Organic Selenium in Dandelions

“…Li's research showed that after treating B. juncea with different concentrations of Na 2 SeO 3 , the proportion of SeMet in the aboveground part was the highest, while MeSeCys and SeMet in the roots were the highest. Moreover, the increase in SeMet content in the roots effectively reduces the transportation of Cd to the aboveground part [34]. In this study, when dandelion was treated with 8 mg/L Na 2 SeO 3 , the total Se content reached 25.97 mg/kg, with organic Se accounting for 99.37%, which was of great significance for dietary Se supplementation.…”

“…In this study, CNGC1 is a cyclic nucleotide-gated ion channel, and its high expression mediates the physiological and biochemical response of dandelion in the transport of Se to plant root cells under Na 2 SeO 3 treatment (Figure 12). In contrast to previous studies [12,34,48,50,52], the identification of these genes in dandelions treated with selenium offers valuable insights into the molecular mechanisms underlying selenium absorption and transport in crops, thus providing new supplements to the existing knowledge in this field.…”