오이덩굴쪼김병균 Fusarium oxysporum f. sp. cucumerinum의 소형분생포자는 물한천배지상에서 Fe-EDDHA를 처리하였을 때 시간이 경과됨에 따라 발아율이 증가되어 무처리와 유의차를 보이지 않았으나 발아관의 길이는 현저하게 짧았다. Pseudomonas putid의 Siderophore를 처리하였을 때는 포자의 발아율과군사신장이 모두 현저하게 억제되었다. 토양중에 형성된 후막포자가 발아하는데 필요한 영양물질로 Glucose, Peptone을 각각 씩 첨가하였을 때 에 달하는 높은 발아율을 나타냈고, Glucose 와 Asparagine 를 첨가한 처리도 의 발아율을 보였다. 오이의 근권토양에서 후막포자는 발아후 10일된 유묘에서 의 발아율을 보인 반면 2일된 유묘에서는 정도 밖에 안되었으며, 10일 이상 경과된 묘에서도 발아율이 증가되지 않았다. 근권토양에 Fe-EDDHA를 첨가한 처리와 P. putida를 접종한 처리는 후막포자의 발아를 현저히 억제하였으며, 근권부위에 영양물질을 첨가한 처리에서도 같은 경향이었다. 그러나 비근권토양에 영양물질을 첨가하여 후막포자를 발아시켰을 경우 Fe-EDDHA나 P. putida의 발아 억제 효과가 뚜렷하게 인정되지 않았다. 근권토양에서 후막포자 발아 억제효과는 Fe-EDDHA보다 P. putida를 접증한 처리가 더 큰것으로 나타났다.

초 록 본 연구는 우리나라 주요 산림해충중 흰불나방, 오리나무잎벌레 및 솔잎혹파리 방제 대책의 일환으로 미생물 병원체를 조사하고져 실시하였다. 흰불나방에서 분리된 징충물은 핵다각체 Virus와 Bacillus sp. 일종이엇는데 살충효과는 무처리 에 대해 각각 와 로서 핵다각체 Virus의 경우가 우수하였다. 오리나무잎벌레에서는 세균과 진균 각 1종씩 분리되었는데 그중 진균만이 병원성을 보였으며 이는 백강균의 1종인 Beauveria bassiana로 동정되었고 이 균의 살충력은 무처리구 에 비해 의 높은 비율을 나타내었다. 솔잎혹파리에서는 모두 15종의 미생물이 분리동정되었으나 그중 3개의 세균종류와 3개의 진균이 병원성을 나타냈으며 가장 병원성이 강했던 것은 Fusarium sp.였고 그 다음이 Bacillus sp. I과 Spicaria sp.의 순서였다. 1957연부터 1977연에 걸쳐 솔잎혹파리에서 분리된 병원미생물을 흰불나방 및 오리나무잎벌레에 접종한 결과 어느 경우나 병원성을 인정할 수 없었다.

This study investigated microbial communities and their diversity in a full-scale mesophilic anaerobic digester treating sewage sludge. Influent sewage sludge and anaerobic digester samples collected from a wastewater treatment plant in Busan were analyzed using high-throughput sequencing. It was found that the microbial community structure and diversity in the anaerobic digester could be affected by inoculation effect with influent sewage sludge. Nevertheless, distinct microbial communities were identified as the dominant microbial communities in the anaerobic digester. Twelve genera were identified as abundant bacterial communities, which included several groups of syntrophic bacteria communities, such as Candidatus Cloacimonas, Cloacimonadaceae W5, Smithella, which are (potential) syntrophic-propionate-oxidizing bacteria and Mesotoga and Thermovigra, which are (potential) syntrophic-acetate-oxidizing bacteria. Lentimicrobium, the most abundant genus in the anaerobic digester, may contribute to the decomposition of carbohydrates and the production of volatile fatty acids during the anaerobic digestion of sewage sludge. Of the methanogens identified, Methanollinea, Candidatus Methanofastidiosum, Methanospirillum, and Methanoculleus were the dominant hydrogenotrophic methanogens, and Methanosaeta was the dominant aceticlastic methanogens. The findings may be used as a reference for developing microbial indicators to evaluate the process stability and process efficiency of the anaerobic digestion of sewage sludge.

This study aimed to investigate the effects of dietary Ptecticus tenebrifer on the fecal microbiomes of bichon frise. A total of 16 bichon frise dogs (average weight, 2 kg) were randomly allotted to 4 dietary treatments (4 dogs/group): general pet food, two types of domestic pet food containing Ptecticus tenebrifer, and one imported pet food containing Ptecticus tenebrifer. In the controls, Firmicutes accounted for the highest proportion (82%) at the phylum level in the fecal microbiomes. The Tax4Fun2's functional prediction program indicated that the control groups showed a relatively high amount of obesity-related microorganisms; the pathways included three types of carbohydrate metabolism. Among the treatments, Firmicutes abundances was the least in the treatments with the two types of domestic pet food containing Ptecticus tenebrifer; this did not affect the functional prediction of Tax4Fun2. In conclusion, the two types of domestic feed with Ptecticus tenebrifer were healthy and suitable for bichon frise; they could be beneficial in terms of obesity.

The present study investigated the effect of ammonia load on microbial communities in mesophilic anaerobic digestion of propionic acid. A laboratory-scale continuous anaerobic digester treating propionic acid as a sole organic substrate was operated under non-inhibitory condition and inhibitory conditions with ammonia (1.5 g and 3.5 g ammonia-N/L, respectively), and bacterial and archaeal communities in the steady states of each ammonia condition were analyzed using high-throughput sequencing. Thirteen bacterial families were detected as abundant bacterial groups in mesophilic anaerobic digestion of propionic acid. Increase in ammonia concentration resulted in significant shifts in microbial community structures. Syntorophobacter, Pelotomaculum, and Thermovigra were determined as the dominant groups of (potential) propionate oxidizing bacteria in the non-inhibitory condition, whereas Cryptanaerobacter and Aminobacterium were the dominant groups of (potential) propionate oxidizing bacteria in the ammonia-inhibitory condition. Methanoculleus and Methanosaeta were the dominant methanogens. Acetate-oxidation coupled with hydrogenotrophic methanogenesis might be enhanced with increases in the relative abundances of Methanoculleus and Tepidanaerobacter acetatoxydans under the ammonia-inhibitory condition. The results of the present study could be a valuable reference for microbial management of anaerobic digestion systems that are exposed to ammonia inhibition and propionic acid accumulation.

To improve the environmental management and resources, in this study, we aimed to investigate the effect of adding oyster shell powder to Hanwoo manure on its characteristics and microbial composition during the storage period. Additives were deposited on top of the manure surface at the rate of 0, 0.5, and 1% of oyster shell powder per 200 g of Hanwoo manure in a plastic container with three replicates; however, untreated manure litter served as the control. Manure characteristics (dry matter, organic matter and crude ash) and microbial composition (lactic acid bacteria, yeast, Bacillus subtilis, Salmonella, and E.coli) were evaluated at day 0, 2, 4, and 8. Manure characteristics exhibited an effect on dry matter, organic matter, and crude ash at day 2 and 8 (p<0.05), and not for day 0 and 4 (p>0.05). With the exception of yeast content at day 4 of storage, lactic acid bacteria, yeast, Bacillus subtilis, Salmonella, and E.coli exhibited no significant differences in all conditions during the storage period. Conclusively, addition of 1% oyster shell powder to Hanwoo manure resulted in slightly better manure characteristics; however, its microbial composition remained unchanged.

Soil microorganism activity in an agricultural field is affected by various factors including climate conditions, soil chemical properties, and crop cultivation. In this study, we elucidate the correlation between microorganism activity and agricultural environment factors using the dehydrogenase activity (DHA) value, which is one of the indicators of soil microbial activity. As a result, the various factors noted above were related to the DHA value. Annual rainfall, soil Mg2+, bacterial and fungal diversities, types of crops, developmental stages, seasons, and cultivation status were highly correlated with the DHA value. Furthermore, next-generation sequencing (NGS) analysis was used to identify that the type of crop affected soil microbial compositions of both bacteria and fungi. Soil used for soybean cultivation showed the highest relative abundance for Verrucomicrobia, Planctomycetes, and Acidobacteria but Actinobacteria and Firmicutes had the lowest relative abundance. In the case of soil used for potato cultivation, Actinobacteria had the highest relative abundance but Proteobacteria had the lowest relative abundance. Armatimonadetes showed the highest relative abundance in soil used for cabbage cultivation. Among the fungal communities, Mortierellomycota had the highest relative abundance for soybean cultivation but the lowest relative abundance for cabbage cultivation; further, Rozellomycota, Chytridiomycota, and Cercozoa had the highest relative abundance for cabbage cultivation. Basidiomycota had the highest relative abundance for potato cultivation but the lowest relative abundance for soybean cultivation.

To develop eco-friendly microbial inoculants, siderophore-producing bacteria were isolated and identified, and their production characteristics and plant growth-promoting abilities were investigated. A strain S21 was isolated from rhizosphere of Korean perilla (Perilla frutescens) and identified as Enterobacter amnigenus by phenotypic properties and 16S rRNA gene sequencing. The highest siderophore production was obtained in a medium containing 0.5% fructose, 0.1% urea, 0.5% K2HPO4 and 0.1% succinic acid. By using this improved medium, siderophore production increased by 2.5 times compared to that of basal medium. The strain S21 showed insoluble phosphate solubilizing, ammonification and antifungal activities, and also produced hydrolytic enzymes (protease and lipase), indoleacetic acid and 1-aminocyclopropane-1-carboxylate deaminase. Our data suggest that E. amnigenus S21 is a potential candidate that can be used as eco-friendly biocontrol agent and biofertilizer.

Agricultural practices are known to have a crucial influence not only on soil physico-chemical properties but also on microbial communities. To investigate the effect of farming practices on soil microbial communities, a total of 10 soil samples were collected, including five conventional and five organic farming soils cultivated with peppers in plastic greenhouse. We conducted barcorded-pyrosequencing of V1-V3 regions of 16S rRNA genes to examine soil microbial communities of two different farming practices. Taxonomic classification of the microbial communities at the phylum level indicated that a total of 22 bacterial phyla were present across all samples. Among them, seven abundant phyla (>3%) including Proteobacteria, Actinobacteria, Firmicutes, Acidobacteria, Bacteroidetes, Chloroflexi, and Gemmatimonadetes were found, and Proteobacteria (33.0 ± 5.7%), Actinobacteria (19.9 ± 9.7%), and Firmicutes (13.6 ± 5.0%) comprised more than 66% of the relative abundance of the microbial communities. Organic farming soils showed higher relative abundances of Proteobacteria and Firmicutes, while Actinobacteria and Chloroflexi were more abundant in conventional farming soils. Notably, the genera Bacillus (higher in organic farming soils) and Streptomyces (higher in conventional farming soils) exhibited significant variation in relative abundance between organic and conventional farming soils. Finally, correlation analysis identified significant relationships (p<0.05) between soil chemical properties, in particular, pH and organic matter content and microbial communities. Taken together, this study demonstrated that the changes of soil physico-chemical properties by agricultural farming practices effected significantly (p<0.05) on soil microbial communities.