Integration of transcriptome and metabolome analyses reveals sorghum roots responding to cadmium stress through regulation of the flavonoid biosynthesis pathway

Abstract

Cadmium (Cd) pollution is a serious threat to plant growth and human health. Although the mechanisms controlling the Cd response have been elucidated in other species, they remain unknown in Sorghum (Sorghum bicolor (L.) Moench), an important C4 cereal crop. Here, one-week-old sorghum seedlings were exposed to different concentrations (0, 10, 20, 50, 100, and 150 μM) of CdCl2 and the effects of these different concentrations on morphological responses were evaluated. Cd stress significantly decreased the activities of the enzymes peroxidase (POD), superoxide dismutase (SOD), glutathione S-transferase (GST) and catalase (CAT), and increased malondialdehyde (MDA) levels, leading to inhibition of plant height, decreases in lateral root density and plant biomass production. Based on these results, 10 μM Cd concentration was chosen for further transcription and metabolic analyses. A total of 2683 genes and 160 metabolites were found to have significant differential abundances between the control and Cd-treated groups. Multi-omics integrative analysis revealed that the flavonoid biosynthesis pathway plays a critical role in regulating Cd stress responses in sorghum. These results provide new insights into the mechanism underlying the response of sorghum to Cd.

Transcriptomics and metabolomics association analysis revealed the responses of Gynostemma pentaphyllum to cadmium

“…In this study, Cd treatment showed a dwarf phenotype on G. pentaphyllum , underscoring the detrimental effects of Cd, and was consistent with previous studies ( Li et al., 2022b ). Prior research had demonstrated that treatment with Cd in sorghum and wheat seedlings had toxic effects and this was concentration-dependent ( Jiao et al., 2023 ; Zhang et al., 2023 ). Cd treatment with low concentrations (1.6 mg/L -1 ) manifested the best stimulatory growth when compared to high concentrations (6.5 mg/L -1 ) in young peppermint plants ( Wang et al., 2023 ).…”

“…Analysis of DEGs found that they were associated with specific biological pathways, oxidoreductase activity, protein kinase activity and protein phosphorylation, indicating that the G. pentaphyllum seedlings could efficiently activate its defense system and induce the expression of stress-related genes to counter act the Cd toxicity it encountered ( Figure S2 and Table S3 ). In prior studies, it was demonstrated that Cd stress exerted a substantial impact on the expression levels of DEGs which were related to amino acid, carbohydrate, and nucleotide biosynthetic pathways in sorghum and S. nigrum ( Wang et al., 2022 ; Jiao et al., 2023 ). These DEGs exhibited marked induction in the biosynthesis of other secondary metabolites, carbohydrate, amino acid and lipid metabolism, as well as signal transduction pathway, which were stimulated in response of G. pentaphyllum to Cd stress ( Figure S3 ).…”

“…The TCA cycle-related metabolites, citric acid, such as α-ketoglutaric acid, L-(-)-malic acid, succinic acid and fumaric acid, were significantly accumulated after Cd treatment ( Tables S3 , S4 and Figure 4D ), implying that they may play a vital role in maintaining energy support balance during Cd stress. Flavonoids, as secondary metabolites, are mainly used to reduce Cd poisoning through chelation and passivation in plants and these can help to confer Cd resistance ( Li et al., 2015 ; Zhu et al., 2020 ; Jiao et al., 2023 ). Flavonoids, including luteolin-7-O-(6’’-malonyl) glucoside-5-O-rhamnoside, quercetin-3-O-glucoside (isoquercitrin), quercetin-3-O-galactoside (hyperin), kaempferol-3-O-robinobioside (biorobin) and quercetin-7-O-glucoside were found to be accumulated during Cd treatment ( Figure 4D ), and there must be is involved in the Cd response of G. pentaphyllum .…”

“…In addition, some crucial metabolisms that directly protect cells from Cd stress were highlighted. For example, the metabolism of galactose, lipid, and glutathione in buckwheat ( Huo et al., 2023 ), and the ABC transporter, phenylpropanoid biosynthesis and flavonoid biosynthesis pathway in sorghum ( Jiao et al., 2023 ); the unsaturated fatty acids, amino acids (including phenylalanine), nucleotides, sulfur compounds, flavonoids, glutathione and lignin biosynthetic metabolism in Pistia stratiotes were also implicated ( Wei et al., 2023 ). The metal-transport genes related to Cd uptake, transport, and detoxification have also been extensively investigated.…”

Transcriptome & Metabolic Profiling: An Insight Into the Abiotic Stress Response Crosstalk in Plants

“…In addition, some crucial metabolisms that directly protect cells from Cd stress were highlighted. For example, the metabolism of galactose, lipid, and glutathione in buckwheat (Huo et al, 2023), and the ABC transporter, phenylpropanoid biosynthesis and flavonoid biosynthesis pathway in sorghum (Jiao et al, 2023); the unsaturated fatty acids, amino acids (including phenylalanine), nucleotides, sulfur compounds, flavonoids, glutathione and lignin biosynthetic metabolism in Pistia stratiotes were also implicated (Wei et al, 2023). The metal-transport genes related to Cd uptake, transport, and detoxification have also been extensively investigated.…”