Boron (B) deficiency and copper (Cu) excess are common problems in citrus orchard soils. Citrus sinensis seedlings were exposed to 25 (B25) or 2.5 (B2.5) mu M H3BO3 and 0.5 (Cu0.5) or 350 (Cu350) mu M CuCl3 for 24 weeks. Cu350 upregulated 2210 (1012) genes and 482 (341) metabolites and downregulated 3201 (695) genes and 175 (43) metabolites in roots at B2.5 (B25). Further analysis showed that the B-mediated mitigation of Cu toxicity in roots involved the coordination of the following aspects: (a) enhancing the ability to maintain cell wall and plasma membrane stability and function; (b) lowering the impairment of Cu350 to primary and secondary metabolisms and enhancing their adaptability to Cu350; and (c) alleviating Cu350-induced oxidative stress via the coordination of reactive oxygen species (ROS) and methylglyoxal detoxification systems. Cu350 upregulated the abundances of some saccharides, amino acids and derivatives, phospholipids, secondary metabolites, and vitamins, and the expression of several ROS detoxification-related genes in roots of B2.5-treated seedlings (RB2.5), but these adaptive responses did not prevent RB2.5 from Cu-toxicity (oxidative damage). The study identified some genes, metabolites, and metabolic processes/pathways possibly involved in root Cu tolerance. Additionally, the responses of gene expression and metabolite profiling to Cu-B treatments differed between leaves and roots. Therefore, this study provided novel information for B to reduce Cu toxicity in roots and might contribute to the development of soil amendments targeting Cu excess in citrus and other crops.

Contamination of vegetables with heavy metals and microplastics is a major environmental and human health concern. This study investigated the role of taurine (TAE) in alleviating arsenic (As) and polyvinyl chloride microplastic (MP) toxicity in broccoli plants. The experiment followed a completely randomized design with four replicates per treatment. Plants were grown in soil spiked with MP (200 mg kg-1), As (42.8 mg kg-1), and their combination (As + MP) with or without taurine (TAE; 100 mg L-1) foliar supplementation. Results demonstrated that MP, As, and As + MP toxicity markedly decreased growth, chlorophyll content, photosynthesis, and nutrient uptake in broccoli plants. Exposure to individual or combined MP and As increased oxidative damage, indicated by elevated methylglyoxal (MG), superoxide radical (O2 & sdot;-), hydrogen peroxide (H2O2), hydroxyl radical (& sdot;OH), and malondialdehyde (MDA) levels alongside intensified lipoxygenase (LOX) activity and leaf relative membrane permeability (RMP). Histochemical analyses revealed higher lipid peroxidation, membrane damage as well as increased H2O2 and O2 center dot- levels in the leaves of stressed plants. Micropalstic and As toxicity deteriorated anatomical structures, with diminished leaf and root epidermal thickness, cortex thickness, and vascular bundle area. However, TAE improved the antioxidant enzyme activities, endogenous ascorbate-glutathione pools, hydrogen sulfide and nitric oxide levels that reduced H2O2, O2 & sdot;-, & sdot;OH, RMP, MDA, and activity of LOX. Taurine elevated osmolyte accumulation that protected membrane integrity, resulting in increased leaf relative water content and plant biomass. Plants supplemented with TAE demonstrated improved anatomical structures, resulting in diminished As uptake and its associated phytotoxicity. These findings highlight that TAE improved redox balance, osmoregulation, ion homeostasis, and anatomical structures, augmenting tolerance to As and MP toxicity in broccoli.

As an important medicinal plant, Panax notoginseng often suffers from various abiotic and biotic stresses during its growth, such as drought, heavy metals, fungi, bacteria and viruses. In this study, the symptom and physiological parameters of cucumber mosaic virus (CMV)-infected P. notoginseng were analyzed and the RNA-seq was performed. The results showed that CMV infection affected the photosynthesis of P. notoginseng, caused serious oxidative damage to P. notoginseng and increased the activity of several antioxidant enzymes. Results of transcriptome analysis and corresponding verification showed that CMV infection changed the expression of genes related to plant defense and promoted the synthesis of P. notoginseng saponins to a certain extent, which may be defensive ways of P. notoginseng against CMV infection. Furthermore, pretreatment plants with saponins reduced the accumulation of CMV. Thus, our results provide new insights into the role of saponins in P. notoginseng response to virus infection.