The Agricultural Biology Department consists of three divisions. The Sericulture and Apiculture is in charge of promoting related industries by doing basic and applied researches to develop bioactive functional materials from mulberry, silkworm and honeybee. The Industrial Insect Division is responsible for the development of the industrial use of insects, including pollinators, scavengers and environment-friendly pet insects, and the packaging of teaching and other materials. The Agricultural Microbiology Division provides services for the evaluation of bio-rational formulations, management and classification of useful agricultural microorganisms including mushrooms, and development of methods for their application to sustainable agriculture.
The Department made remarkable achievements in 2011. These include 138 articles published in world-renowned journals, 33 patents secured, 81 patent applications filed, and 66 technologies transferred to the private sector. Among the outstanding results that the scientists in the department generated were two researches which were included in the 100 national best R&D achievements.
Sericulture and Apiculture
Breeding of New Mulberry (Morus alba L.) Cultivar, Sangchon-ppong, for Fruit Production
The new mulberry cultivar, Sangchon-ppong, was selected for fruit production from the mulberry genetic resources field at Suwon. After 6 years (2006 to 2011) of regional adaptability tests in three sites using the line name Sannchonjosaeng, it was officially registered as Sangchon-ppong. Compared to the control cultivar Chungil-ppong, Sangchon-ppong matures 5-7 days earlier and has a 12% higher fruit yield for three harvesting years. The fruit is black purple with a mean fruit weight of 2.9 g and a 14.9 ° Brix reading for soluble solids. Sangchon-ppong has a wide range of adaptability, except in places where cold damage often occurs.
Integrated Pest and Disease Management in Honeybee Hives
The Korean sacbrood virus (KSBV) is the pathogen of the sacbrood disease, which poses a serious threat to honeybee (Apis cerana), and tends to cause a bee colony and even the whole apiary to collapse. We have determined the nucleotide sequence (8,792 bp length) of KSBV causing a fatal infection on the honeybee larvae. The effect of the immunologic adjuvant can be increased twofold in the A. cerana hives in the Cheungwon-Gun apiary. The environmental miticide consists of citrus peel, FGMO, tymol, honey and wax. It was able to knock the snot out of Varroa destructor with more than 87% kill rate, and Tropilaelaps clareae with more than 55% kill rate.
Biological Effects of Treatment of an Animal Skin Wound with Honeybee (Apis mellifera L.) Venom
The wound sizes were small in the bee venom group compared to the control and Vaseline groups. The BV group demonstrated decreased TGF-Β1, fibronectin and VEGF mRNA levels, and increased collagen-I mRNA levels. The expressions of TGF-Β1, fibronectin and VEGF proteins were significantly lower in the BV group compared to the control group, while the expression of collagen-I was increased in the BV group as indicated by immunohistochemical staining.
Development of Novel Uses of Sericultural Products and Silk Protein
Silkworm powder was examined to develop a novel drug using specific Korean silkworm varieties. Nuegra was investigated for functional food registration. The female pupa was elucidated as good for osteoporosis. Experiments with animals showed that silk protein has a good potential for osteoporosis and cartilage cell culture. The silk eardrum patch was licensed by the Korean Food and Drug Administration for mass production.
Development of Silkworm Biotechnology for Production of Useful Materials
To produce the recombinant human granulocyte macrophage colony-stimulating factor 2 (hGM-CSF), two types of transgenic silkworms were designed to be secreted into the whole body and the lumen of posterior silk glands(Fig. 1). These transgenic silkworms successfully produced recombinant hGM-CSF2 in the whole body and cocoon fiber.
Fig. 1. Development of transgenic silkworms producing recombinant hGM-CSF.
Industrial Insect Division
Investigation and conservation of insects
A total of 11,448 individuals were collected in the survey of insect and spider resources. From this survey, Mastax formosana Dupuis, 1912 belonging to Carabidae of Coleoptera was found as new to the Korean fauna. Of the total collections, 6,071 insect samples were made into dried specimens, while 527 spider samples were preserved in 99% ethyl alcohol. And then, we taxonomically identified and arranged 6,007 individuals of 361 species of 31 families in Hemiptera and Lepidoptera, and their taxonomic information were constructed in the database for specimen management using Excel program. In DNA barcode analyses, all of 202 Korean native butterfly species were successfully analyzed for molecular identification. However, we examined that DNA barc oding was extremely unavailable from 30-60 year-old dry specimens because DNA degradation of these samples has progressed under 300bp length. To resolve this program, a direct sequencing using species-specific overlapping primer sets per species was employed to construct of full length for DNA barcoding region and successfully obtained the sequences from 60 butterfly species. Introducing long-horned beetles and singing insects into the market place has begun, based on the establishment of a stable and continuous system of production. A total of 17 endangered insect species were successfully maintained under laboratory conditions. In addition, cabbage butterfly and a few other insect species that are produced on a large rearing scale on newly developed artificial diet were used for education material.
Utilization of the Black Soldier Fly for High-tech Fusion-based Environment Remediation and Development of High Value-added Substance
The larvae of the black soldier fly, Hermetia illucens (Diptera: Strationmyidae), are a detritivore which eat organic materials such as animal carcasses and food wastes that various microorganisms commonly colonize. In 2011, the outstanding achievements generated by this research included a) the technical method for indoor mating and egg-laying of H. illucens under the 500-watt Halogen lamp; b) the biochemical characterization and analysis of the digestive enzymes in H. illucens; c) isolation of two microorganisms which secret antibacterial substance; d) purification of antibacterial material from black soldier larvae; and e) the registration of the black soldier fly by-products as fertilizer production (Public notice in RDA, 2011-49). These research achievements were highlighted the best 100 national R&D results in 2011.
Effect of Foraging Activity of Pollinators and Productivity Increase of Major Agricultural Crops
The rate of blueberry fruit setting when pollinated by Bombus terrestris was recorded at 87.7%, 89.6% under Apis mellifera, and 66.5% with Osmia cornifrons as pollinator. Compared to natural field conditions, the economic benefits to blueberry crop productivity of using B. terrestris as pollinators was higher by 9% and 15% when using A. mellifera. Under vinyl-house conditions, the fruit set rate of apricot was higher when pollinated by A. mellifera (92%) and B. terrestris (89%) compared to the control (83%). Consequently, the economic benefit to the apricot crop when A. mellifera was used as pollinator, compared with natural field conditions, was higher by 4% and 10% when B. terrestris was used. For welsh onion (Allium fistulosum) pollinated by B. terrestris, an economic benefit of 3.4% higher in the breeder's case was obtained.
Effects of the Synthetic Coprisin Analog Peptide, CopA3, in Pathogenic Microorganisms and Mammalian Cancer Cells
A synthetic coprisin analog peptide, 9-mer dimer CopA3 was designed based on a defensin-like peptide, Coprisin, isolated from the bacteria-immunized dung beetle, Copris tripartitus. CopA3 was investigated for its antimicrobial activity and cancer cell growth inhibition. CopA3 exhibited antimicrobial activities against various pathogenic bacteria and yeast fungus with MIC values in the 2-32 μM range, and inhibited the cell viabilities of pancreatic and hepatocellular cancer cells in a dose-dependent manner, except MIAPaca2, Hep3B, and HepG2 cells. The average IC50 values of CopA3 was 61.7 μM against pancreatic cancer cells, and 67.8 μM against hepatocellular cancer cells.
Agricultural Microbiology Division
Korean Agricultural Culture Collection (KACC)
KACC is national culture collection which is responsible for the collection and management of agriculture- and food-related microorganisms. The mission of KACC is based on the national law "The preservation, management and utilization for the agricultural genetic resources". KACC has collected microbial strains from diverse sources such as nine national sub-banks of microorganisms and the foreign culture collections like CBS of Netherlands, and NBRC of Japan. In 2011, a total of 1,823 strains, including 1,003 strains of bacteria and 820 strains of fungi, were newly registered at the KACC. The overall number of microbial strains registered has reached 15,297 at the end of 2011. The registered strains were stored in the database of KACC homepage (www.genebank.go.kr). Also, a total of 3,395 strains, consisting of 1,516 bacterial and 1,876 fungal strains, were distributed to universities, research institutes and private companies for the purpose of microbial researches.
Mapping Soil Bacterial Communities of Paddy Soils in Korea
To study how soil bacterial communities of paddy soils are affected by specific environmental changes or disturbances, 230 soil samples were collected across Korea in collaboration with nine Agricultural Research & Extension Services (Fig. 2). The average microbial biomass was 517.4 mg kg-1 with a range of 2.0-2,471.0, while average dehydrogenase activity was 65.1 μg TPF g124 h1 with a range of 3.3-447.0. Through high-quality screening of 1,104,229 16S rRNA pyrosequences, 132,633 operational taxonomic units (OTU) were found to exist in 230 soils studied. We estimated about 313,402 and 236,935 putative species based on Ace and Chao richness estimator, respectively. The dominant phyla of soil bacteria were Proteobacteria (36.7%), Chloroflexi (15.7%), Actinobacteria (12.5%) and Acidobacteria (10.4%). This study provides the first comprehensive map of bacterial communities in the paddy soils of Korea.
Fig. 2. Location of sampling sites for bacterial community analysis (left), and phylum-level distributions of soil bacteria (right).
Research on Microorganisms for Pest Biological Control
The cucumber leaf disk method as a bioassay was developed to select promising strains for the biological control of the cucumber downy mildew. The prototype of the mycoparasite, Trichoderma spp., at 1.0-4.2x107 spore/g was mass produced in solid medium for the biological control of white rot. An isolate of Isaria javania Pf 04 showed the highest virulence against sweetpotato whitefly (Bemisia tabaci). High relative humidity for 24 hours after spore treatment was important to get high control efficiency. Seventeen kinds of environment-friendly agricultural materials had no influence on the conidia of the biopesticide Botanigard (Beauveria bassiana GHA).
Granulation of Beneficial Peptides and Identification of Secondary Metabolites from Bacillus sp.
To enhance their control value, paromomycin and fusaricidin of ISR agents were impregnated with 0.3% alginic acid and kaoline (300 g/L). The soil treatment using 0.1 % fusaricidin granules showed excellent control value against bacterial soft rot caused by Pectobacterium carotovora SCC1 compared with soil drenched with fusaricidin with the same concentration. In the study on bacterial metabolites, five kinds of cyclic lipopeptides were identified after purifying the bacterial suspension of Bacillus vallismortis EXTN-1(Fig. 3). Each metabolite of CLP showed different antibiotic activities against major pathogens and induced systemic resistance against Phytophthora capsici. Among five (5) derivatives of iturins, iturin A4 showed the strongest activity against Colletotricum acutatum, Botrytis cinerea, Fusarium oxysporum and Sclerotinia sclerotiorum but not to Phytophthora capsici.