• Journal of Plant Biotechnology
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• 제37권4호
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• pp.465-471
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• 2010

We assessed whether the cow1 mutant defects are associated with growth of Tos17 and T-DNA insertional rice in blue light (BL). Growth of oscow1 mutants which encoded a member of the YUCCA protein family was retarded in BL. Root to shoot ratios of the mutants were reduced about 2 times lower in the absence of NAA and about 2.5 times lower in the presence of NAA; the shoot growth was not significantly changed by NAA addition. Photosynthetic activity of the mutants was however inhibited in high light. Pigment analysis showed significant difference between wild-type (Chl a:b = 3.02) and mutants (3.84). Carotenoid contents of the mutants were also decreased considerably, implying the involvement of cow1 in pigment formation. These findings lead us to suggest that the growth retardation of oscow1 mutant plants by BL results from the difference of photosynthetic activity in part.

• 한국지하수토양환경학회지:지하수토양환경
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• 제26권5호
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• pp.1-8
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• 2021

A series of pot experiments were conducted to quantitatively estimate inhibitory effects of reclaimed soil on the growth of Lentil (Lens culinaris) with two soils remediated by land farming (DDC) and low temperature thermal desorption(YJ), respectively. After cultivation in a growth chamber for 8 days, plants were harvested for the analysis of 8 indices including chlorophyll-a and carotenoid in leaves, shoot fresh weight, root dry weight, root length, number of later roots, specific root length (SRL) as well as germination rate in comparison to control experiment conducted on nursery soil. Root length was estimated by SmartRoot program from the digital images of the roots. The results showed germination rate on YJ and DDC soil decreased 29 and 71%, respectively. In comparison to the control, the averaged value of the 8 indices for YJ and DDC soil showed overall growth inhibition was 48 and 68%, respectively. When the same experiment was conducted with 25% (W/W) vermiculate amended soil, plant growth on each soil was comparable to that of the control. The results implies reclaimed soils requires additional processes and/or amendments to reuse for plant growth.

• Journal of Microbiology and Biotechnology
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• 제22권11호
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• pp.1549-1556
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• 2012

Endophytic fungi were isolated from roots of six halophytes in Suncheon Bay. The endophytic fungi of 35 species isolated from halophytes were identified by internal transcribed spacer (ITS) containing the ITS1, 5.8s, and ITS2 regions. All fungal strains were analyzed to diversity at the genus level. Fungal culture filtrates (FCF) of endophytic fungi were treated to Waito-c rice (WR) seedling for plant growth-promoting verification. It was confirmed that fungal strain Sj-2-2 provided plant growth promotion (PGP) to WR seedling. Then, PGP of Suaeda japonica was confirmed by treating culture filtrate of Sj-2-2. As a result, it was verified that culture filtrate of Sj-2-2 had more advanced PGP than positive control when treated to S. japonica. The secondary metabolites involved in culture filtrate of Sj-2-2 were identified by HPLC and GC-MS SIM analysis. The presence of physiologically bioactive gibberellins (GAs) and other inactive GAs in culture filtrate of Sj-2-2 was detected. The molecular analysis of sequences of Sj-2-2 showed the similarity to Penicillium sp. of 99% homology. The PGP of Sj-2-2 as well as symbiosis between endophytic fungi and halophytes growing naturally in salt marsh was confirmed. Sj-2-2 was identified as a new fungal strain producing GAs by molecular analysis of sequences. Consequently, the Sj-2-2 fungal strain was named as Penicillium sp. Sj-2-2. In this study, the diversity of endophytic fungi isolated from roots of halophytes in salt marsh and the PGP of a new gibberellin-producing fungal strain were confirmed.

• 한국환경복원기술학회지
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• 제4권1호
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• pp.98-109
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• 2001

This study aimed to investigate the effect of revegetation technique for water attacking point using waterlogged prevention frame revetment. In this study, we evaluate frame revetment stability, water quality, plant growth and ecological and envirnomental changes in Mooshim streamside landscape. The results are as follows; 1) The waterlogged prevention frame revetment appeared to be stable despite of two big floods. The materials used for the revetment were not eroded on the water attacking point. Thus, we confirmed the effect of scour prevention of the frame work. 2) The effects of the frame revetment on the water quality appeared to be good for the surrounding environment. Dissolved Oxygen(DO) was higher about $0.4{\sim}0.6mg/{\ell}$ at the frame revetment than that of the main stream flow. pH value was lower about 0.4~0.5. Electric Conductivity(EC) showed lower about $0.8{\sim}1.1{\mu}s/cm$. at submersion prevent frame than the low-flow of the stream. Turbidity was lower about $0.6{\sim}1.2mg/{\ell}$. 3) As the effects on ecological and environmental conditions, we discovered a number of carassius auratus and Zacco platypus in the frame revetment area. Also, sympetrum balteata, coenagrionidae was observed frequently. 4) The plant growth did not appear to tumble or wither despite of two big floods. The visual rating of plant growth was evaluated as medium (around 5 point) 5) The landscape analysis derived four factors(i.e. the harmony, the variation, the flexibility and the provincial characteristics) from the factor analysis.

• Plant Biotechnology Reports
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• 제2권1호
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• pp.21-31
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• 2008

In plants, the oxygen generated by photosynthesis can be excited to form reactive oxygen species (ROS) under excessive sunlight. Excess ROS including singlet oxygen ($^1O_2$) inhibit the growth, development and photosynthesis of plants. To isolate ROS-resistant crop plants, we used paraquat (PQ), a generator of $O_2{^-}$ as a source of screening and mutagen, and obtained two PQ-resistant lines in Pisum sativum, namely R3-1 and R3-2. Both lines showed greater resistance to PQ than their wild type (WT) siblings with respect to germination, root growth, and shoot growth. Biochemical analysis showed differences in these lines, in which ROS-scavenging enzymes undergo changes with a distinguishable increase in Mn-SOD. We further observed that the cytosolic catalases (CATs) in leaves in both lines were shifted in a native-PAGE analysis compared with that of the WT, indicating that the release of bound $^1O_2$ was enhanced. Phenotypic analysis revealed distinguishable differences in leaf development, and in flowering time and position. In addition, R3-1 and R3-2 showed shorter individual inter-node lengths, dwarf plant height, and stronger branching compared with the WT. These results suggested that PQ-induced ROS-resistant Pisum have the potential pleiotropic effects on flowering time and stem branching, and that ROS including $^1O_2$ plays not only important roles in plant growth and development as a signal transducer, but also appears as a strong inhibitor for crop yield.

• 농업과학연구
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• 제37권3호
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• pp.377-382
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• 2010

An auxin-producing bacterium (AMT-54) was isolated from ginseng cultivating soil of Geumsan area. The isolate AMT-54 was confirmed to produce indole-3-acetic acid (IAA) which is one of auxin hormone by TLC analysis. When the concentration of IAA was assessed by performing HPLC quantitative analysis, the maximal 457ppm of IAA was detected from the culture filtrate after culturing in R2A broth containing 0.1% tryptophan for 24h at $35^{\circ}C$. The molecular weight of the main peak obtained by LC-mass analysis was correspondent well to 175, that of IAA. The strain AMT-54 was identified as a novel species belongs to Klebsiella mobilis by a chemotaxanomic and phylogenetic analysis. To investigate the growth promoting effect of crop, when the culture broth of K. mobilis AMT-54 was infected onto seed pot of mung bean, the adventitious root induction and root growth of mung bean were 3.3times higher than control.

• Journal of Microbiology and Biotechnology
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• 제21권8호
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• pp.777-790
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• 2011

To elucidate the biodiversity of plant growth-promoting rhizobacteria (PGPR) in Korea, 7,638 bacteria isolated from the rhizosphere of plant species growing in many different regions were screened. A large number of PGPR were identified by testing the ability of each isolate to promote the growth of cucumber seedlings. After redundant rhizobacteria were removed via amplified rDNA restriction analysis, 90 strains were finally selected as PGPR. On the basis of 16S ribosomal RNA sequences, 68 Gram-positive (76%) and 22 Gram-negative (24%) isolates were assigned to 21 genera and 47 species. Of these genera, Bacillus (32 species) made up the largest complement, followed by Paenibacillus (19) and Pseudomonas (11). Phylogenetic analysis showed that most of the Grampositive PGPR fell into two categories: low- and high- G+C (Actinobacteria) strains. The Gram-negative PGPR were distributed in three categories: ${\alpha}$-proteobacteria, ${\beta}$- proteobacteria, and ${\gamma}$-proteobacteria. To our knowledge, this is the largest screening study designed to isolate diverse PGPR. The enlarged understanding of PGPR genetic diversity provided herein will expand the knowledge base regarding beneficial plant-microbe interactions. The outcome of this research may have a practical effect on crop production methodologies.

• Journal of Microbiology and Biotechnology
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• 제31권9호
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• pp.1241-1255
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• 2021

This study was carried out to explore a non-chemical strategy for enhancing productivity by employing some antagonistic rhizobacteria. One hundred eighteen bacterial isolates were obtained from the rhizospheric zone of various crop fields of Gangwon-do, Korea, and screened for antifungal activity against Fusarium wilt (Fusarium oxysporum f. sp. lactucae) in lettuce crop under in vitro and in vivo conditions. In broth-based dual culture assay, fourteen bacterial isolates showed significant inhibition of mycelial growth of F. oxysporium f. sp. lactucae. All of the antagonistic isolates were further characterized for the antagonistic traits under in vitro conditions. The isolates were identified on the basis of biochemical characteristics and confirmed at their species level by 16S rRNA gene sequencing analysis. Arthrobacter sulfonivorans, Bacillus siamensis, Bacillus amyloliquefaciens, Pseudomonas proteolytica, four Paenibacillus peoriae strains, and Bacillus subtilis were identified from the biochemical characterization and 16S rRNA gene sequencing analysis. The isolates EN21 and EN23 showed significant decrease in disease severity on lettuce compared to infected control and other bacterial treatments under greenhouse conditions. Two bacterial isolates, EN4 and EN21, were evaluated to assess their disease reduction and growth promotion in lettuce in field conditions. The consortium of EN4 and EN21 showed significant enhancement of growth on lettuce by suppressing disease caused by F. oxysporum f. sp. lactucae respectively. This study clearly indicates that the promising isolates, EN4 (P. proteolytica) and EN21 (Bacillus siamensis), can be commercialized and used as biofertilizer and/or biopesticide for sustainable crop production.

• The Plant Pathology Journal
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• 제37권3호
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• pp.307-314
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• 2021

Pepper (Capsicum annuum L.) is an important agricultural crop worldwide. Recently, Colletotrichum scovillei, a member of the C. acutatum species complex, was reported to be the dominant pathogen causing pepper anthracnose disease in South Korea. In the present study, we isolated bacterial strains from rhizosphere soil in a pepper field in Gangwon Province, Korea, and assessed their antifungal ability against C. scovillei strain KC05. Among these strains, a strain named BS1 significantly inhibited mycelial growth, appressorium formation, and disease development of C. scovillei. By combined sequence analysis using 16S rRNA and partial gyrA sequences, strain BS1 was identified as Bacillus velezensis, a member of the B. subtilis species complex. BS1 produced hydrolytic enzymes (cellulase and protease) and iron-chelating siderophores. It also promoted chili pepper (cv. Nockwang) seedling growth compared with untreated plants. The study concluded that B. velezensis BS1 has good potential as a biocontrol agent of anthracnose disease in chili pepper caused by C. scovillei.

• Journal of Microbiology and Biotechnology
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• 제17권8호
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• pp.1361-1368
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• 2007

Endophytic bacteria associated with the roots of coastal sand dune plants were isolated, taxonomically characterized, and tested for their plant growth-promoting activities. Ninety-one endophytic bacterial isolates were collected and assigned to 17 different genera of 6 major bacterial phyla based on partial 16S rDNA sequence analyses. Gammaproteobacteria represented the majority of the isolates (65.9%), and members of Pseudomonas constituted 49.5% of the total isolates. When testing for antagonism towards plant pathogenic fungi, 25 strains were antagonistic towards Rhizoctonia solani, 57 strains were antagonistic towards Pythium ultimum, 53 strains were antagonistic towards Fusarium oxysporum, and 41 strains were antagonistic towards Botrytis cinerea. Seven strains were shown to produce indole acetic acid (IAA), 33 to produce siderophores, 23 to produce protease, 37 to produce pectinase, and 38 to produce chitinase. The broadest spectra of activities were observed among the Pseudomonas strains, indicating outstanding plant growth-promoting potential. The isolates from C. kobomugi and M. sibirica also exhibited good plant growth-promoting potential. The correlations among individual plant growth-promoting activities were examined using phi coefficients, and the resulting data indicated that the production of protease, pectinase, chitinase, and siderophores was highly related.