J_Environmetal Microbiology and Engineering

Virulence of Entomopathogenic Fungus Lecanicilium sp. Le85
towards Cotton Aphid
Van Hanh VU* 1 , Dinh Thi QUYEN 2 , Xuan Dat VU 2 , Huu Quan NGUYEN 2
and Keun KIM 3
1
Institute of Biotechnology, Vietnam Academy of Science and Technology, Hanoi
10600, Vietnam/ Department of Bioscience and Biotechnology, The University of
Suwon, Hwaseong-si 445-743, Korea. 2 Institute of Biotechnology, Vietnam
Academy of Science and Technology, Hanoi 10600, Vietnam. 3 J-60
Department of
Bioscience and Biotechnology, The University of Suwon, Hwaseong-si 445-743,
Korea.
*Corresponding author: vvhanh@ibt.ac.vn
Twenty-two entomopathogenic fungal strains were used for laboratory
bioassay against aphid Aphis gossypii living on cucumber leaves. Among
them, four strains of Lecanicillium spp. isolated from infected aphid’s
cadavers had high virulence towards A. gossypii causing 84 to 100%
mortality after 5 to 7 days of conidial treatment. Especially, one fungus
Lecanicillium sp. Le85 showed the highest virulence towards development
and reproduction of A. gossypii. At 20~24 o C and relative humidity of
75~85%, after 5 days of application with 1x10 8 conidia of Le85 /ml, A.
gossypii did not develop and exhibited a mortality of 100% with LT50
of 2.6 days. Moreover, at 25~31 o C and relative humidity of 60~70%,
the mortality of A. gossypii by Le85 was about 95 ~100% after 5 days
with LT50 of 2.8 days. These results suggested the potential role of Le85
for use as microbial control agent against A. gossypii in greenhouses.
Keywords: Cotton aphids Aphis gossypii, entomopathogenic fungi,
Lecanicillium sp.
J-61
Partial Identification of Microorganisms from Artificially
Constructed Tunnel and Dokdo Soil to Develop Antifungal
Construction Material
Jong-Myong PARK, Sung-Jin PARK and Sa-Youl GHIM*
School of Life Sciences, Kyungpook National University, Daegu 702-701, Korea.
*Corresponding author: eveningwater@hanmail.net
To develop antifungal concrete, we sampled microorganisms from the
tunnel to determine the most widely distributed fungal strain. In addition,
we are finding the multi-functional (antifungal and calcite forming)
bacterium from the Dokdo soil. Isolation and pure culture of bacterium
and fungi were done using potato dextrose agar and several bacteriological
media.As the result of partial identification, fungal strain showed the
closest homologies with Penicillium sp., Tritirachium sp., Elsinoaceae sp.,
Cladosporium spp., Alternaria spp., Pestalotiopsis cocculi, Pseudozyme
prolifica or Aureobasidium pullulans, respectively. Each bacterial strains
showed the closest similarity with Rhodococcus erythropolis (99.794%),
Bacillus aryabhattii (99.791%) or Bulkholderia glathei (96.369%),
respectively. The most widely distributed fungal strain was Cladosporium
spp. As the result of the calcite forming assay, 52 Dokdo derived bacterial
strains and five tunnel derived strains were identified as calcite forming
bacteria (CFB). Qualitative antimycotic assay showed that 23 Dokdo and
two tunnel derived CFB strains have antimycotic activity against
Aspergillus niger KCTC6906 and Cladosporium spp. using the strain's
crude liquid culture.
Keywords: Antifungal, Construction, Material.
2011 International Symposium & Annual Meeting
Novel Esterases Isolated from Marine Sediment Metagenome
So-Hyeon SEO 1 , Sang-Hong YOON 1 , Young-Seok LEE 1 ,
Sung-Gyun KANG 2 , Jung-Hyun LEE 2 and Chang-Muk LEE* 1
1
Functional Biomaterial Division, National Academy of Agricultural Science,
Rural Development Administration, Suwon 441-707, Korea. 2 J-62
Korea Ocean
Research and Development Institute, Ansan 426-744, Korea.
*Corresponding author: changmuk@rda.go.kr
Metagenomes from uncultured microbial communities are rich sources
for identifying novel biocatalysts. With deep sea sediments at an island,
Dokdo, we have constructed the metagenomic libraries comprising total
60,672 fosmid clones. A fosmid clone with lipolytic activity was selected
by functional screening of the metagenomic libraries using tributyrin agar
plates. To identify genes, a shot-gun library was constructed from the
selected clone by random shearing. Further functional screening of the
shot-gun library revealed one novel clones. The sequence analysis of the
clone revealed the presence of an open reading frame encoding acidic
polypeptide of 59.4kDa (553 amino acids, pI of 4.45) with the highest
homology to a carboxyl esterase from δ-proteobacterium Haliagium
ochaceum DSM 14365(44% identity, 61% similarity). The sequence
analysis showed that the protein harbors the typical catalytic triad formed
by Ser229, Asp347 and His461. Multiple sequence alignments with known
carboxyl esterases showed the clone belongs to the carboxylesterase BioH
member, which is involved in biotin biosynthesis in Aromatoleum
aromaticum [This experiment is supported by grants from the Rural
Development Administration project number PJ0067032011 and IPET
project number 110037-03-1-HD110].
Keywords: carboxylesterase, metagenome, dokdo
K_ Host-Microbe Interactions
K-1
Aphids Feeding Manipulates Host Plant Immunity against Plant
Pathogens
Choong-Min RYU* and Soohyun LEE
Laboraytory of Bio-industry and Biochemistry Research Center, KRIBB 111
Gwahangno, Yuseong-gu, Daejeon 305-806, S. Korea.
*Corresponding author: cmryu@kribb.re.kr
Plants modulate defense signaling networks to response against different
biotic stresses. In this work, we evaluated whether insect infestation can
change of plant defense mechanism charging to subsequent pathogen
attack. Aphids and/or a chemical trigger benzothiadiazol (BTH) was
pretreated seven days before challenging two pathogenic bacteria,
Xanthomonas axonopodis pv. vesicatoria (Xav) as a compatible pathogen
and X. axonopodis pv. glycines 8ra (Xag 8ra) as an incompatible pathogen.
Disease severity was noticeably lower in aphid and BTH + aphid
treatments than control. BTH or aphids alone treatment did not differ
induction of hypersensitive response (HR) against Xag 8ra. However, the
combination treatment showed synergistically to reduced HR appearance.
Pretreatment of BTH resulted in significant reduction of aphids population.
Expression of the two defense-related genes, Capsicum annum
Pathogenesis-related genes 1 (CaPR1) and CaPR4 revealed that aphid
infestation primes resistance genes resulting in induction of systemic
defense response against compatible and incompatible pathogens. Taken
together, our results suggest that insect feeding itself elicits propound plant
resistance and help plant coping subsequent attack of pathogens.
Keywords: Aphid, immunity, Xanthomonas
The Korean Society for Microbiology and Biotechnology
411