Journal of Microbiology

Review

MINIREVIEW] Dynamics of microbial communities and CO2 and CH4 fluxes in the tundra ecosystems of the changing Arctic: Min Jung Kwon , Ji Young Jung , Binu M. Tripathi , Mathias Göckede , Yoo Kyung Lee , Mincheol Kim; J. Microbiol. 2019;57(5):325-336. Published online January 16, 2019; DOI: https://doi.org/10.1007/s12275-019-8661-2

Abstract: Arctic tundra ecosystems are rapidly changing due to the amplified effects of global warming within the northern high latitudes. Warming has the potential to increase the thawing of the permafrost and to change the landscape and its geochemical characteristics, as well as terrestrial biota. It is important to investigate microbial processes and community structures, since soil microorganisms play a significant role in decomposing soil organic carbon in the Arctic tundra. In addition, the feedback from tundra ecosystems to climate change, including the emission of greenhouse gases into the atmosphere, is substantially dependent on the compositional and functional changes in the soil microbiome. This article reviews the current state of knowledge of the soil microbiome and the two most abundant greenhouse gas (CO2 and CH4) emissions, and summarizes permafrost thaw-induced changes in the Arctic tundra. Furthermore, we discuss future directions in microbial ecological research coupled with its link to CO2 and CH4 emissions.

Research Support, Non-U.S. Gov'ts

NOTE] Molecular Phylogenetic Status of Korean Strain of Podosphaera xanthii, a Causal Pathogen of Powdery Mildew on Japanese Thistle (Cirsium japonicum) in Korea: Hyang Burm Lee; J. Microbiol. 2012;50(6):1075-1080. Published online December 30, 2012; DOI: https://doi.org/10.1007/s12275-012-2618-z

Abstract: Powdery mildew diseases are sensitive to climate change and spread can be favored by increased temperature and low moisture. During 2011 to 2012, a powdery mildew disease by a Podosphaera species was observed on the leaves of Japanese thistle (Cirsium japonicum) in Korea. The initial sign of this disease included scattered superficial white mycelia on leaves. As the disease progressed, abundant necrotic black spots exhibiting chasmothecia were formed on the leaves. rDNA ITS and 28S homologies of the fungus (EML-CSPW1) showed 100% identity values with those regions from many strains of P. xanthii (syn. P. fusca) via NCBI BLASTN search.

Seasonal Changes in Nitrogen-Cycle Gene Abundances and in Bacterial Communities in Acidic Forest Soils: Jaejoon Jung , Jinki Yeom , Jiwon Han , Jisun Kim , Woojun Park; J. Microbiol. 2012;50(3):365-373. Published online June 30, 2012; DOI: https://doi.org/10.1007/s12275-012-1465-2

Abstract: The abundance of genes related to the nitrogen biogeochemical cycle and the microbial community in forest soils (bacteria, archaea, fungi) were quantitatively analyzed via real-time PCR using 11 sets of specific primers amplifying nifH, bacterial amoA, archaeal amoA, narG, nirS, nirK, norB, nosZ, bacterial 16S rRNA gene, archaeal 16S rRNA gene, and the ITS sequence of fungi. Soils were sampled from Bukhan Mountain from September of 2010 to July of 2011 (7 times). Bacteria were the predominant microbial community in all samples. However, the abundance of archaeal amoA was greater than bacterial amoA throughout the year. The abundances of nifH, nirS, nirK, and norB genes changed in a similar pattern, while narG and nosZ appeared in sensitive to the environmental changes. Clone libraries of bacterial 16S rRNA genes were constructed from summer and winter soil samples and these revealed that Acidobacteria was the most predominant phylum in acidic forest soil environments in both samples. Although a specific correlation of environmental factor and gene abundance was not verified by principle component analysis, our data suggested that the combination of biological, physical, and chemical characteristics of forest soils created distinct conditions favoring the nitrogen biogeochemical cycle and that bacterial communities in undisturbed acidic forest soils were quite stable during seasonal change.

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