Interaction between the Accumulation of Cadmium and Deoxynivalenol Mycotoxin Produced by Fusarium graminearum in Durum Wheat Grains

Deoxynivalenol induces spleen damage, apoptosis, and inflammation in mice by increasing mitochondrial reactive oxygen species: Protective effects of curcumin

Deoxynivalenol (DON), a Fusarium mycotoxin, causes spleen apoptosis and inflammation, which damage the organ. Curcumin (Cur) is a member of the ginger family. It has anti-apoptotic and anti-inflammatory effects that maintain the health of the organism's immune system. Here, the protective effects of Cur against DON-induced spleen damage were explored. First, we found DON (2.4 mg/kg body weight) decreased the expression of manganese superoxide dismutase, mitochondrial membrane potential, adenosine triphosphate, and disturbed hematoxylin and eosin staining in mice spleen. The results confirmed that DON causes mitochondrial reactive oxygen species (mtROS) overproduction leading to spleen damage. Second, we found DON decreased the expression of mitochondrial apoptosis-inducing factor (AIF) and B-cell lymphoma-2 (Bcl-2), and increased the expression of nuclear AIF, Bcl2-associated X (Bax), cysteine-aspartate protease-3 (caspase-3), caspase-9. Mitoquinone is a mitochondria-targeted antioxidant that can prevent of mitochondrial oxidative damage. These expression increases were not observed in the mitoquinone-treated group, confirming that mtROS was an upstream regulatory target of apoptosis and inflammation in DON-exposed mice spleens. Finally, we confirmed that Cur (50 or 100 mg/kg body weight) attenuated DON-induced apoptosis and inflammation by inactivating mtROS. Collectively, these results confirm that DON causes spleen damage by increasing mtROS, and the protective effects of curcumin.

Cadmium immobilization by mercapto-palygorskite in alkaline soil: Impacts on soil microbial communities and wheat rhizosphere metabolism

Weakly alkaline cadmium (Cd) contaminated soil in China has aroused great concern regarding its impact on food security and human health. Mercapto-modified palygorskite (MP) has exhibited good potential to minimize Cd accumulation in wheat, it is imperative to understand the underlying mechanisms within the soil-wheat-microbial system for sustainable development of agrochemicals. This study evaluated the effects of various MP dosages on soil Cd bioavailability, rhizosphere metabolomics, microbial community structure and wheat growth. The results indicated that MP (0.05-0.2 %) application significantly reduced Cd accumulation in wheat grains by 59.0-83.2 % (p < 0.05) and inhibited Cd translocation from root to grain. MP also promoted Mn oxide formation and redistributed the exchangeable Cd to Fe-Mn oxide-bound forms (44.2-109.6 %), thus lowering soil Cd bioavailability by 17.9-32.5 %. Additionally, MP reduced wheat rhizosphere organic acid levels, altered rhizosphere carbon and nitrogen pools, and stimulated the growth of Cd-tolerant Alternaria and Cladosporium, while inhibiting the growth of Fusarium. These findings highlight the potential of MP to modulate soil rhizosphere metabolism and microbial communities, offering a novel perspective on its environmental implications and supporting agrochemical sustainability.

Effect of cadmium and polystyrene nanoplastics on the growth, antioxidant content, ionome, and metabolism of dandelion seedlings

Cadmium is the most prevalent heavy metal pollutant in the environment and can be readily combined with micro/nanoplastics (M/NPs) to change their bioavailability. In the present study, we comprehensively investigated the effect of polystyrene (PS) NPs on dandelion plants grown under Cd stress. Cd exposure significantly inhibited the growth of dandelion seedlings, resulting in a decrease in seedling elongation from 26.47% to 28.83%, a reduction in biomass from 29.76% to 54.14%, and an exacerbation of lipid peroxidation and oxidative stress. The interaction between PS NPs and Cd resulted in the formation of larger aggregates, with the Cd bioavailability reduced by 12.56%. PS NPs affect ion absorption by regulating reactive oxygen production and increasing superoxide dismutase activity, thereby mitigating the adverse effects of Cd. PSCd aggregates induced significant changes in the metabolic profiles of dandelions, affecting various carbohydrates related to alcohols, organic acids, sugar metabolism, and bioactive components related to flavonoids and phenolic acids. Furthermore, based on a structural equation model, exposure to PSCd activated oxidative stress and nutrient absorption, thereby affecting plant growth and Cd accumulation. Overall, our study provides valuable insights into the effects of PS NPs on Cd bioavailability, accumulation, and plant growth, which are crucial for understanding the food safety of medicinal plants in a coexistence environment.

Nucleoside Diphosphate Kinase FgNdpk Is Required for DON Production and Pathogenicity by Regulating the Growth and Toxisome Formation of Fusarium graminearum

Nucleoside diphosphate kinases (NDPKs) are nucleotide metabolism enzymes that play different physiological functions in different species. However, the roles of NDPK in phytopathogen and mycotoxin production are not well understood. In this study, we showed that Fusarium graminearum FgNdpk is important for vegetative growth, conidiation, sexual development, and pathogenicity. Furthermore, FgNdpk is required for deoxynivalenol (DON) production; deletion of FgNDPK downregulates the expression of DON biosynthesis genes and disrupts the formation of FgTri4-GFP-labeled toxisomes, while overexpression of FgNDPK significantly increases DON production. Interestingly, FgNdpk colocalizes with the DON biosynthesis proteins FgTri1 and FgTri4 in the toxisome, and coimmunoprecipitation (Co-IP) assays show that FgNdpk associates with FgTri1 and FgTri4 in vivo and regulates their localizations and expressions, respectively. Taken together, these data demonstrate that FgNdpk is important for vegetative growth, conidiation, and pathogenicity and acts as a key protein that regulates toxisome formation and DON biosynthesis in F. graminearum.