Metabolic Responses to Manganese Toxicity in Soybean Roots and Leaves

Abstract

Soybean is one of the most crucial beans in the world. Although Mn (manganese) is a kind of important nutritive element helpful to plant growth and health, excess Mn is harmful to crops. Nevertheless, the effect of Mn toxicity on soybean roots and leaves metabolism is still not clear. To explore this, water culture experiments were conducted on the development, activity of enzyme, and metabolic process of soybeans under varying levels of Mn treatment (5 and 100 μM). Compared with the control, the soybeans under Mn stress showed inhibited growth and development. Moreover, the activity of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), ascorbate peroxidase (APX), and the soluble protein content in leaves and roots of soybean were all increased. However, soluble sugar and proline contents in soybean roots and leaves showed the opposite trend. In addition, the Mg (magnesium) and Fe (iron) ion contents in soybean leaves significantly decreased, and the Mn ion content greatly increased. In roots, the Mn and Fe ion content increased, whereas the Mg ion content decreased. Furthermore, the metabolomic analysis based on nontargeted liquid chromatography–mass spectrometry identified 136 and 164 differential metabolites (DMs) that responded to Mn toxicity in roots and leaves of soybean, respectively. These DMs might participate in five different primary metabolic pathways in soybean leaves and roots, suggesting that soybean leaves and roots demonstrate different kinds of reactions in response to Mn toxicity. These findings indicate that Mn toxicity will result in enzymes activity being changed and the metabolic pathway being seriously affected, hence inhibiting the development of soybean.

Genome-Wide Identification of AhMDHs and Analysis of Gene Expression under Manganese Toxicity Stress in Arachis hypogaea

“…Mn toxicity occurs when the available Mn content in the soil exceeds the typical Mn concentration required by the plant. Plants show evident evidence of poisoning on their leaves as a consequence, such as dark spots, crinkled leaves, and chlorosis; Mn poisoning also affects roots, resulting in a decrease in lateral root count and dry weight, in addition to the signs found on the leaves [33]. The findings in this study revealed that AhMDHs are differentially expressed in the roots and leaves of peanut subjected to Mn toxicity stress.…”

“…When the available Mn content in the soil exceeds the normal Mn concentration needed by a plant, the plant is likely to suffer from Mn toxicity. Plants, as a result, display obvious signs of poisoning on their leaves, such as dark patches, crinkled leaves, and chlorosis; Mn poisoning also affects roots, resulting in reduced lateral root count and dry weight, in addition to the signs on the leaves [33]. Excess Mn prevents the absorption and transfer of other essential elements, such as calcium, magnesium, iron, and phosphorus, possibly because of the similar ionic radii or binding strength of ligands [34].…”

Physiological Mechanism through Which Al Toxicity Inhibits Peanut Root Growth

“…The NRAMP family is highly important for metal absorption and transportation in plants, with most AhNRAMPs being primarily expressed in androecia, roots, and immature seeds [ 55 ]. MTPs are also vital for bivalent cation transport in plants [ 86 ]. Previous studies have linked NRAMPs and MTPs to the transportation of bivalent metal ions such as Fe 2+ and Cd 2+ [ 55 , 87 ].…”

“…The dry root samples (0.15 g) were completely dissolved in nitric acid (Guangzhou Reagent, Guangzhou, China). The levels of Al, Mg, Na, K, Fe, Ca, Mn, Zn, Cu, and Se in peanut roots were tested using PS7800 ICP–AES (inductively coupled plasma atomic emission spectrometry) (Hitachi, Tokyo, Japan) [ 86 , 97 ]. Each index was analyzed using three biological replicates.…”

Metabolomics and physio-chemical analyses of mulberry plants leaves response to manganese deficiency and toxicity reveal key metabolites and their pathways in manganese tolerance

“…For instance, Nazari et al (2018) reported that progressively increasing Mn concentrations in Mentha aquatica plants simultaneously increased the contents of flavonoids, anthocyanins, malonaldehyde (MDA), hydrogen peroxide (H 2 O 2 ), and activated antioxidant enzymes, such as SOD, CAT, and APX (Nazari et al, 2018). Apart from the antioxidant mechanisms, plants also cope with Mn toxicity by deploying or activating their tolerance mechanisms via regulation of Mn uptake (transport), translocation, and distribution within the plant cells (Wang et al, 2023). Some of these transporters (transport mechanisms) have been reported and include AtNramp1, and AtNramp3, OsNramp1, and OsNramp5, identified in Arabidopsis and rice, respectively (Socha and Guerinot, 2014;Chang et al, 2020).…”