Rural Development Administration

About: Rural Development Administration is a government organization based out in Jeonju, South Korea. It is known for research contribution in the topics: Gene & Population. The organization has 4372 authors who have published 4919 publications receiving 94318 citations.

Effects of air temperature and air flow rate control on the tipburn occurrence of leaf lettuce in a closed-type plant factory system

Abstract: This study aimed to establish a practical method to reduce tipburn symptoms on leaf lettuce cultivars in a closed plant factory system, focusing on air temperature conversion at specific plant growth stages and artificial air flow application strategies using pre-screened tipburn-sensitive cultivars. Inter-conversion effect of day temperature among 18, 22, and 25°C, 12 days after transplanting on tipburn occurrences, were compared with stable day temperature condition. Horizontal air flow rates were controlled at 0.28 (Low), 0.55 (Medium), and 1.04 m·s−1 (High). Tipburn occurrences were highly variable depending on the lettuce cultivars tested. Following the initial screening of 28 leaf lettuce cultivars under 3 different light intensity conditions (ranging from 150 to 250 mol·m−2·s−1), two cultivars exhibiting relatively higher percentages of tipburn were selected for the following air temperature and air flow treatments. None of the temperature treatments effectively reduced tipburn symptom, while adjusting the temperature to a lower day temperatures at 12 days after transplanting only had a minor effect on lettuce growth and tipburn occurrence. In contrast, stable horizontal 24-hour air flow rates above 0.28 m·s−1 effectively reduced tipburn symptom, with no significant differences being found among the tested air flow rates, while above 65% of tipburned plants were found in the control plot of 0.08 m·s−1 flow rate. When stable air flow was applied, compared to the control, there was an increase in the absolute calcium content and a decrease in the calcium content difference between the inner and outer lettuce leaves. This calcium balance change may have occurred due to the enhanced transpiration in the inner parts of plants. This study showed that stable horizontal air flow application along cultivation beds is more effective than air temperature control in decreasing tipburn symptoms in a closed plant factory system.

Massilia niabensis sp. nov. and Massilia niastensis sp. nov., isolated from air samples.

Abstract: Two bacterial isolates, designated strains 5420S-26T and 5516S-1T, were recovered from air samples collected in Suwon, Korea. Cells of both strains were aerobic, Gram-negative, motile rods. Phylogenetically, these strains were positioned within the radius of the genus Massilia. 16S rRNA gene sequence analysis showed that the strains shared 97.3 % sequence similarity and had sequence similarities of 94.9–98.1 % with respect to type strains of species belonging to the genus Massilia. In DNA–DNA hybridization tests, the two strains showed <39 % relatedness with respect to strains of closely related species of the genus Massilia and 27 % relatedness to each other. Both strains contained Q-8 as the predominant isoprenoid quinone and possessed summed feature 3 (comprising C16 : 1 ω7c and/or iso-C15 : 0 2-OH) as the major fatty acid. Strain 5516S-1T was found to contain the fatty acid C20 : 0 (in small amounts), a feature that served to distinguish it from both 5420S-26T and recognized members of the genus Massilia. The DNA G+C contents of 5420S-26T and 5516S-1T were 67.8 and 66.6 mol%, respectively. Phylogenetic, phenotypic and chemotaxonomic data accumulated in this study revealed that 5420S-26T and 5516S-1T represent novel species of the genus Massilia, for which the names Massilia niabensis sp. nov. (type strain 5420S-26T =KACC 12632T =DSM 21312T) and Massilia niastensis sp. nov. (type strain 5516S-1T =KACC 12599T =DSM 21313T) are proposed, respectively.

Agricultural pesticide usage and prioritization in South Korea.

Abstract: This study aims to review agricultural pesticide usage and trends and to identify hazardous pesticides for regulation, in terms of public health, in South Korea. The authors collected data on usage and trends of agricultural pesticides through agriculture-related databases. Criteria from the US Environmental Protection Agency classification for carcinogenicity, World Health Organization classification for acute toxicity, and European Union prioritization list for endocrine-disrupting chemicals were used for the hazard categorization of identified individual active ingredients. Pesticides to be prioritized among all pesticides used in South Korea between 2007 and 2011 were selected by taking into account the volume of usage, toxicity, and epidemiological evidence. Annual agricultural use of pesticides has increased rapidly from the 1970s to 1990s in South Korea, but has declined since 2001. The quantity of pesticides used in 2011 was reported as 19,131 tons, and was comprised of 34.7% insecticides,...

Functional identification of oleate 12-desaturase and ω-3 fatty acid desaturase genes from Perilla frutescens var. frutescens.

Abstract: We described identification, expression, subcellular localization, and functions of genes that encode fatty acid desaturase enzymes in Perilla frutescens var. frutescens. Perilla (Perilla frutescens var. frutescens) seeds contain approximately 40 % of oil, of which α-linolenic acid (18:3) comprise more than 60 % in seed oil and 56 % of total fatty acids (FAs) in leaf, respectively. In perilla, endoplasmic reticulum (ER)-localized and chloroplast-localized ω-3 FA desaturase genes (PfrFAD3 and PfrFAD7, respectively) have already been reported, however, microsomal oleate 12-desaturase gene (PfrFAD2) has not yet. Here, four perilla FA desaturase genes, PfrFAD2-1, PfrFAD2-2, PfrFAD3-2 and PfrFAD7-2, were newly identified and characterized using random amplification of complementary DNA ends and sequence data from RNAseq analysis, respectively. According to the data of transcriptome and gene cloning, perilla expresses two PfrFAD2 and PfrFAD3 genes, respectively, coding for proteins that possess three histidine boxes, transmembrane domains, and an ER retrieval motif at its C-terminal, and two chloroplast-localized ω-3 FA desaturase genes, PfrFAD7-1 and PfrFAD7-2. Arabidopsis protoplasts transformed with perilla genes fused to green fluorescence protein gene demonstrated that PfrFAD2-1 and PfrFAD3-2 were localized in the ER, and PfrFAD7-1 and PfrFAD7-2 were localized in the chloroplasts. PfrFAD2 and perilla ω-3 FA desaturases were functional in budding yeast (Saccharomyces cerevisiae) indicated by the presence of 18:2 and 16:2 in yeast harboring the PfrFAD2 gene. 18:2 supplementation of yeast harboring ω-3 FA desaturase gene led to the production of 18:3. Therefore, perilla expresses two functional FAD2 and FAD3 genes, and two chloroplast-localized ω-3 FA desaturase genes, which support an evidence that P. frutescens cultivar is allotetraploid plant.

Effects of water-saving irrigation on emissions of greenhouse gases and prokaryotic communities in rice paddy soil.

Abstract: The effects of water-saving irrigation on emissions of greenhouse gases and soil prokaryotic communities were investigated in an experimental rice field. The water layer was kept at 1–2 cm in the water-saving (WS) irrigation treatment and at 6 cm in the continuous flooding (CF) irrigation treatment. WS irrigation decreased CH4 emissions by 78 % and increased N2O emissions by 533 %, resulting in 78 % reduction of global warming potential compared to the CF irrigation. WS irrigation did not affect the abundance or phylogenetic distribution of bacterial/archaeal 16S rRNA genes and the abundance of bacterial/archaeal 16S rRNAs. The transcript abundance of CH4 emission-related genes generally followed CH4 emission patterns, but the difference in abundance between mcrA transcripts and amoA/pmoA transcripts best described the differences in CH4 emissions between the two irrigation practices. WS irrigation increased the relative abundance of 16S rRNAs and functional gene transcripts associated with Anaeromyxobacter and Methylocystis spp., suggesting that their activities might be important in emissions of the greenhouse gases. The N2O emission patterns were not reflected in the abundance of N2O emission-related genes and transcripts. We showed that the alternative irrigation practice was effective for mitigating greenhouse gas emissions from rice fields and that it did not affect the overall size and structure of the soil prokaryotic community but did affect the activity of some groups.