Seed Germination of Sunflower as a Case Study for the Risk Assessment and Management of Transgenic Plants Used for Environmental Remediation in South Korea

Farmland phytoremediation in bibliometric analysis

Phytoremediation is an environmentally friendly, economical, and sustainable technique for restoring farmland. It can remove heavy metals and organic pollutants from the soil through the implementation of hyperaccumulator plants. In recent years, it has garnered significant interest from academic and industrial sectors. This article screened 368 research papers from the Web of Science core collection database related to farmland phytoremediation and conducted a bibliometric analysis of the domain based on CiteSpace. The paper intuitively demonstrates the most influential countries, the most productive institutions, the most contributing groups of authors, and the primary sources of farmland phytoremediation research domain. The findings additionally indicate that the research hotspots include: (1) mechanisms and principles of phytoremediation, (2) the improvement of restoration efficiency, (3) the economic, ecological, and sustainable development of phytoremediation. The exploration of plants with potential to accumulate heavy metals and produce large amounts of biomass is the research frontier within the field of farmland phytoremediation. Additionally, this bibliometric analysis can help scholars willing to work in this research field by concisely understanding the overall research field and frontiers. With the continuous improvement of phytoremediation and its combination with other remediation technologies, the future of farmland remediation will have a promising prospect.

A New Approach for Environmental Risk Assessments of Living Modified Organisms in South Korea

As the development and use of living modified organisms (LMOs) steadily increase, new risk assessment methods that reflect domestic natural ecosystems are being developed. Although LM plants are fundamentally necessary for environmental risk assessment, the introduced gene products and LMO proteins can replace transgenic plants. However, their use is problematic because of instability and indirect assessment data issues. This study proposes a risk assessment tool and scheme for introducing LMO proteins into genetically modified crops. The agroinfiltration method for transient LMO gene expression in plants is a practical tool which can be used to rapidly verify the putative risks of LMO proteins against insects using an LM crop mimic plant with a stably expressed LMO protein. This study used Nicotiana tabacum leaves, which transiently but stably expressed the insecticidal LMO protein Vip3Aa, for LMO risk assessments against Spodoptera litura. The Vip3Aa protein was stably expressed for 5 d in the agroinfiltrated plants, and the protein was active against target insects for environmental LMO risk assessments. In the toxicity evaluation of Vip3Aa-expressing plants against S. litura, the number of deaths was higher in the Vip3Aa-infiltrated N. tabacum-fed group than that in the recombinant Vip3Aa-fed group. In addition, the cumulative number of deaths in the infiltration leaf-fed group was approximately 12-fold higher than that in the protein-fed group under low dosage conditions. This study aimed to develop a transient expression model which can be used to evaluate whether the overall risk of LMO protein is acceptable for use. These results support the usefulness of the transient expression model using an agroinfiltration method as a rapid risk validation tool for LMO proteins against herbivorous insects before producing transgenic plants.

Ecological network analysis reveals distinctive microbial modules associated with heavy metal contamination of abandoned mine soils in Korea

Heavy metal pollution in soil around abandoned mine sites is one of the most critical environmental issues worldwide. Soil microbes form complex communities and perform ecological functions individually or in cooperation with other organisms to adapt to harsh environments. In this study, we investigated the distribution patterns of bacterial and fungal communities in non-contaminated and heavy metal-contaminated soil of the abandoned Samkwang mine in Korea to explore microbial interaction mechanisms and their modular structures. As expected, the bacterial and fungal community structures showed large differences depending on the degree of heavy metal contamination. The microbial network was divided into three modules based on the levels of heavy metal pollution: heavy metal-tolerant (HM-Tol), heavy metal-mid-tolerant (HM-mTol), and heavy metal-sensitive (HM-Sens) modules. Taxonomically, microbes assigned to Vicinamibacterales, Pedosphaeraceae, Nitrosomonadaceae, and Gemmatimonadales were the major groups constituting the HM-Tol module. Among the detected heavy metals (As, Pb, Cd, Cu, and Zn), copper concentrations played a key role in the formation of the HM-Tol module. In addition, filamentous fungi (Fusarium and Mortierella) showed potential interactions with bacteria (Nitrosomonadaceae) that could contribute to module stability in heavy metal-contaminated areas. Overall, heavy metal contamination was accompanied by distinct microbial communities, which could participate in the bioremediation of heavy metals. Analysis of the microbial interactions among bacteria and fungi in the presence of heavy metals could provide fundamental information for developing bioremediation mechanisms for the recovery of heavy metal-contaminated soil.