Functional characterization of a DNA-damage repair/tolerance 100 (DRT100) gene in Sedum alfredii Hance for genome stability maintenance and Cd hypertolerance

Jasmonic acid's impact on Sedum alfredii growth and cadmium tolerance: A physiological and transcriptomic study

Soil cadmium (Cd) pollution is escalating, necessitating effective remediation strategies. This study investigated the effects of exogenous jasmonic acid (JA) on Sedum alfredii Hance under Cd stress, aiming to enhance its phytoextraction efficiency. Initially, experiments were conducted to assess the impact of various concentrations of JA added to environments with Cd concentrations of 100, 300, and 500 μmol/L. The results determined that a concentration of 1 μmol/L JA was optimal. This concentration effectively mitigated the level of ROS products by enhancing the activity of antioxidant enzymes. Additionally, JA fostered Cd absorption and accumulation, while markedly improving plant biomass and photosynthetic performance. In further experiments, treatment with 1 μmol/L JA under 300 μmol/L Cd stress was performed and transcriptomic analysis unveiled a series of differentially expressed genes (DEGs) instrumental in the JA-mediated Cd stress response. These DEGs encompass not only pathways of JA biosynthesis and signaling but also genes encoding functions that influence antioxidant systems and photosynthesis, alongside genes pertinent to cell wall synthesis, and metal chelation and transport. This study highlights that JA treatment significantly enhances S. alfredii's Cd tolerance and accumulation, offering a promising strategy for plant remediation and deepening our understanding of plant responses to heavy metal stress.

Synergistic/antagonistic toxicity characterization and source-apportionment of heavy metals and organophosphorus pesticides by the biospectroscopy-bioreporter-coupling approach

Many anthropogenic chemicals are manufactured and eventually enter the surrounding environment, threatening food security and human health. Considering the additive or synergistic effects of pollutant mixtures, there is an expanding need for rapid, cost-effective and field-portable screening methods in environmental monitoring. This study used a recently developed biospectroscopy-bioreporter-coupling (BBC) approach to investigate the binary toxicity of Ag(I), Cr(VI) and four organophosphorus pesticides (dichlorvos, parathion, omethoate and monocrotophos). Ag(I) and Cr(VI) altered the toxicity mechanisms of pesticides, explained by the synergistic or antagonistic effect of Ag/Cr-induced cytotoxicity and pesticide-induced genotoxicity. The discriminating Raman spectral peaks associated with organophosphorus pesticides were 1585 and 1682 cm-1, but 750, 1004, 1306 and 1131 cm-1 were found in heavy metal and pesticide mixtures. More spectral alterations were related to pesticides rather than Ag(I) or Cr(VI), hinting at the dominant toxicity mechanisms of pesticides in mixtures. Ag(I) supplement significantly increased the levels of reactive oxygen species induced by organophosphorus pesticides, attributing to the increased permeability of cell membrane and entrance of toxic substances into the cells by the oligodynamic actions. This study lends deeper insights into the interactions between microbes and pollutant mixtures, offering clues to assess the cocktail effects of multiple pollutants comprehensively.