Metatranscriptomic analysis reveals active microbes and genes responded to short-term Cr(VI) stress

Metal nanoparticles and pesticides under global climate change: Assessing the combined effects of multiple abiotic stressors on soil microbial ecosystems

The soil is a vital resource that hosts many microorganisms crucial in biogeochemical cycles and ecosystem health. However, human activities such as the use of metal nanoparticles (MNPs), pesticides and the impacts of global climate change (GCCh) can significantly affect soil microbial communities (SMC). For many years, pesticides and, more recently, nanoparticles have contributed to sustainable agriculture to ensure continuous food production to sustain the significant growth of the world population and, therefore, the demand for food. Pesticides have a recognized pest control capacity. On the other hand, nanoparticles have demonstrated a high ability to improve water and nutrient retention, promote plant growth, and control pests. However, it has been reported that their accumulation in agricultural soils can also adversely affect the environment and soil microbial health. In addition, climate change, with its variations in temperature and extreme water conditions, can lead to drought and increased soil salinity, modifying both soil conditions and the composition and function of microbial communities. Abiotic stressors can interact and synergistically or additively affect soil microorganisms, significantly impacting soil functioning and the capacity to provide ecosystem services. Therefore, this work reviewed the current scientific literature to understand how multiple stressors interact and affect the SMC. In addition, the importance of molecular tools such as metagenomics, metatranscriptomics, proteomics, or metabolomics in the study of the responses of SMC to exposure to multiple abiotic stressors was examined. Future research directions were also proposed, focusing on exploring the complex interactions between stressors and their long-term effects and developing strategies for sustainable soil management. These efforts will contribute to the preservation of soil health and the promotion of sustainable agricultural practices.

Trends in Harnessing Plant Endophytic Microbiome for Heavy Metal Mitigation in Plants: A Perspective

Plant microbiomes represent dynamic entities, influenced by the environmental stimuli and stresses in the surrounding conditions. Studies have suggested the benefits of commensal microbes in improving the overall fitness of plants, besides beneficial effects on plant adaptability and survival in challenging environmental conditions. The concept of 'Defense biome' has been proposed to include the plant-associated microbes that increase in response to plant stress and which need to be further explored for their role in plant fitness. Plant-associated endophytes are the emerging candidates, playing a pivotal role in plant growth, adaptability to challenging environmental conditions, and productivity, as well as showing tolerance to biotic and abiotic stresses. In this article, efforts have been made to discuss and understand the implications of stress-induced changes in plant endophytic microbiome, providing key insights into the effects of heavy metals on plant endophytic dynamics and how these beneficial microbes provide a prospective solution in the tolerance and mitigation of heavy metal in contaminated sites.

Heavy Metal Stress Alleviation Through Omics Analysis of Soil and Plant Microbiome

Heavy metal (HM) contamination of soil and water resources is a global concern, which not only limits crop yield and quality, but also has serious environmental effects. Due to the non-biodegradable nature and toxicity, high concentration of HMs in food and environment is a serious threat to the entire ecosystem. Moreover, the target of supplying safe and quality food to the rising human population (expected to reach ~9–10 bn by the year 2050), necessitates effective treatment of the HM-contaminated soil. Various microbe-mediated bioremediation strategies such as biosorption, bioprecipiation, biostimulation, etc., have been found to be effective in uptake and conversion of HMs to less toxic forms. Further, in the past few years, the use of soil and plant-associated microbiome for HM stress alleviation is gaining attention among the scientific community. In general, microbes are spectacular in being dynamic and more responsive to environmental conditions in comparison to their host plants. Moreover, with the advancements in high throughput sequencing technologies, the focus is eventually shifting from just structural characterization to functional insights into the microbiome. The microbes inhabiting the HM-contaminated environments or associated with HM-tolerant plants are a source for exploring HM-tolerant microbial communities, which could be used for enhancing bioremediation efficiency and conferring HM tolerance in plants. This review discusses the application of omics techniques including metagenomics, metatranscriptomics, metaproteomics, and metabolomics, for rapid and robust identification of HM-tolerant microbial communities, mining novel HM resistance genes, and fabricating the HM resistome.