The glutathione-dependent alarm triggers signalling responses involved in plant acclimation to cadmium

Research on the role of bamboo species in the restoration of heavy metal-contaminated soil

Heavy metal contamination in the soil has become more serious due to the rapid development of the economy. Phytoremediation has evoked widespread curiosity in recent years due to its advantages in terms of being environmentally friendly and sustainable. However, there are few reports on the application of bamboo species in the field of phytoremediation, and a comprehensive overview of their potential for restoring contaminated soil by removing heavy metals is lacking. This paper incorporates existing research on bamboo species for the remediation of heavy metal-contaminated soils. It meticulously debates the physiological responses exhibited by bamboo species to heavy metal stress, encompassing growth and development responses, photosynthetic responses, and antioxidant system responses, among others. Furthermore, it elaborates on the capacity of bamboo for heavy metal accumulation and translocation, as well as their remarkable tolerance and detoxification mechanisms. This comprehensive analysis sheds light on the intricate interactions between bamboo and contaminated soil environments. Additionally, the paper summarizes various strategies for the remediation of heavy metal contamination using bamboo species. This review facilitates a more thorough exploration of the potential applications of bamboo species in the remediation of heavy metal-contaminated soils, offering a novel approach for soil environmental restoration.

A multi-omics analysis reveals candidate genes for Cd tolerance in Paspalum vaginatum

Cadmium (Cd) pollution in the farmland has become a serious global issue threatening both human health and plant biomass production. Seashore paspalum (Paspalum vaginatum Sw.), a halophytic turfgrass, has been recognized as a Cd-tolerant species. However, the underlying genetic basis of natural variations in Cd tolerance still remains unknown. This study is possibly the first to apply genome-wide association studies (GWAS) and selective sweep analysis to identify potential Cd stress-responsive genes in P. vaginatum. We identified a total of 89 candidate genes and 656 putative selective sweeps regions. Based on the correlation analysis of differentially expressed metabolites (DEMs) and differentially expressed genes (DEGs), we identified the 55 key genes associated with metabolic changes induced by Cd treatment as the Cd tolerance-related genes. These genes showed significantly higher expression in Cd-tolerant accessions as compared to Cd-susceptive accessions. Therefore, our multi-omics study revealed the molecular and genetic basis of Cd tolerance, which may help develop Cd tolerant crop varieties.

Hydrogen sulfide enhances cadmium tolerance in oilseed rape roots by augmenting glutathione-mediated antioxidant defense and ROS homeostasis

Hydrogen sulfide (H2S) plays a crucial role in regulating plant development and stress responses. Here, the potential role of H2S in enhancing cadmium (Cd) tolerance by modulating the antioxidant defense system and reactive oxygen species (ROS) homeostasis was investigated. The results shown that Cd (II) exposure significantly inhibited the growth and chlorophyll content of rapeseed seedlings. Optimal exogenous sodium hydrosulfide (NaHS; 50 μM) pretreatment markedly alleviated Cd-induced growth inhibition, chlorosis, and root morphology in contrast to increased Cd accumulation in the roots. The DW of the leaves and roots, and the total chlorophyll content increased by 23.8 %, 21.4 % and 114.8 %, respectively. Cd (II)-induced oxidative damage was significantly ameliorated by NaHS application through the reduction of hydrogen peroxide (H2O2) and superoxide (O2•-) accumulation, which were up to 47.3 % and 67.6 %, respectively. Moreover, exogenous NaHS elevated the glutathione (GSH) content and GSH/glutathione disulfide (GSSG) ratio in Cd-stressed roots from 21.9 - 33.3 % and 39.3-87.4 %, respectively. The activity of antioxidant enzymes, with the exception of ascorbate peroxidase, was further elevated by NaHS application. These results suggest that H2S enhances Cd tolerance by augmenting GSH pools and activating antioxidant enzymes to control reactive oxygen species (ROS) homeostasis, thereby ameliorating Cd-induced oxidative stress in rapeseed seedling roots.

The role of gasotransmitter hydrogen sulfide in plant cadmium stress responses

Cadmium (Cd) is a toxic heavy metal that poses a significant risk to both plant growth and human health. To mitigate or lessen Cd toxicity, plants have evolved a wide range of sensing and defense strategies. The gasotransmitter hydrogen sulfide (H2S) is involved in plant responses to Cd stress and exhibits a crucial role in modulating Cd tolerance through a well-orchestrated interaction with several signaling pathways. Here, we review potential experimental approaches to manipulate H2S signals, concluding that research on another gasotransmitter, namely nitric oxide (NO), serves as a good model for research on H2S. Additionally, we discuss potential strategies to leverage H2S-reguated Cd tolerance to improve plant performance under Cd stress.

Cadmium exposure induced light/dark- and time-dependent redox changes at subcellular level in Arabidopsis plants

Cadmium (Cd) is one of the most toxic heavy metals for plants and humans. Reactive oxygen species (ROS) are some of the primary signaling molecules produced after Cd treatment in plants but the contribution of different organelles and specific cell types, together with the impact of light is unknown. We used Arabidopsis lines expressing GRX1-roGFP2 (glutaredoxin1-roGFP) targeted to different cell compartments and analysed changes in redox state over 24 h light/dark cycle in Cd-treated leaf discs. We imaged redox state changes in peroxisomes and chloroplasts in leaf tissue. Chloroplasts and peroxisomes were the most affected organelles in the dark and blocking the photosynthetic electron transport chain (pETC) by DCMU (3-(3,4-dichlorophenyl)-1,1-dimethylurea) promotes higher Cd-dependent oxidation in all organelles. Peroxisomes underwent the most rapid changes in redox state in response to Cd and DCMU and silencing chloroplastic NTRC (NADPH thioredoxin reductase C) considerably increases peroxisome oxidation. Total NAD(P)H and cytosolic NADH decreased during exposure to Cd, while Ca+2 content in chloroplasts and cytosol increased in the dark period. Our results demonstrate a Cd-, time- and light-dependent increase of oxidation of all organelles analysed, that could be in part triggered by disturbances in pETC and photorespiration, the decrease of NAD(P)H availability, and differential antioxidants expression at subcellular level.

Epigenetic alterations in bioaccumulators of cadmium: Lessons from mammalian kidneys and plants

Faced with unpredictable changes in global weather patterns, release and redistribution of metals through land erosion and water movements add to the increasing use of metals in industrial activities causing high levels of environmental pollution and concern to the health of all living organisms. Cadmium is released into the environment by smelting and mining, entering the food chain via contaminated soils, water, and phosphate fertilizers. Bioaccumulation of cadmium in plants represents the first major step into the human food chain and contributes to toxicity of several organs, especially the kidneys, where biomagnification of cadmium occurs over decades of exposure. Even in small amounts, cadmium brings about alterations at the molecular and cellular levels in eukaryotes through mutagenicity, molecular mimicry at metal binding sites and oxidative stress. The epigenome dictates expression of a gene's output through a number of regulatory steps involving chromatin remodeling, nucleosome unwinding, DNA accessibility, or nucleic acid modifications that ultimately impact the transcriptional and translational machinery. Several epigenetic enzymes exhibit zinc-dependence as zinc metalloenzymes and zinc finger proteins thus making them susceptible to deregulation through displacement by cadmium. In this review, we summarize the literature on cadmium-induced epigenetic mechanisms in mammalian kidneys and plants, compare similarities in the epigenetic defense between these bioaccumulators, and explore how future studies could advance our understanding of the cadmium-induced stress response and disruption to biological health.

Sulfate Availability and Hormonal Signaling in the Coordination of Plant Growth and Development

Sulfur (S), one of the crucial macronutrients, plays a pivotal role in fundamental plant processes and the regulation of diverse metabolic pathways. Additionally, it has a major function in plant protection against adverse conditions by enhancing tolerance, often interacting with other molecules to counteract stresses. Despite its significance, a thorough comprehension of how plants regulate S nutrition and particularly the involvement of phytohormones in this process remains elusive. Phytohormone signaling pathways crosstalk to modulate growth and developmental programs in a multifactorial manner. Additionally, S availability regulates the growth and development of plants through molecular mechanisms intertwined with phytohormone signaling pathways. Conversely, many phytohormones influence or alter S metabolism within interconnected pathways. S metabolism is closely associated with phytohormones such as abscisic acid (ABA), auxin (AUX), brassinosteroids (BR), cytokinins (CK), ethylene (ET), gibberellic acid (GA), jasmonic acid (JA), salicylic acid (SA), and strigolactones (SL). This review provides a summary of the research concerning the impact of phytohormones on S metabolism and, conversely, how S availability affects hormonal signaling. Although numerous molecular details are yet to be fully understood, several core signaling components have been identified at the crossroads of S and major phytohormonal pathways.