• Journal of Microbiology and Biotechnology
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• 제20권1호
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• pp.202-207
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• 2010

Plant growth promoting fungi (PGPF) are well known for the production of useful secondary metabolites. However, limited information is available on the gibberellin (GA) production capacity of PGPF of endophytic origin. In the current study, 15 fungal endophytes were isolated from the roots of Crown daisy, and then screened on Waito-c rice, in order to identify plant growth promoting fungi. The fungal isolate MH7 significantly increased the shoot length (12.1 cm) of Waito-c in comparison with control treatment (7.9 cm). In a separate experiment, the culture filtrate (CF) of MH7 significantly promoted the growth attributes of Crown daisy. The MH7 CF was analyzed for gibberellins and it contained all physiologically active gibberellins ($GA_1$, 1.37 ng/ml; $GA_3$, 5.88 ng/ml; $GA_4$, 8.62 ng/ml; and $GA_7$, 2.05 ng/ml) in conjunction with physiologically inactive $GA_9$ (0.83 ng/ml), $GA_{12}$ (0.44 ng/ml), $GA_{15}$ (0.74 ng/ml), $GA_{19}$ (1.16 ng/ml), and $GA_{20}$ (0.98 ng/ml). The CF of MH7 produced higher amounts of $GA_3$, $GA_4$, $GA_7$, $GA_9$, and $GA_{12}$ than wild-type Fusarium fujikuroi, which was used as a control for GA production. The fungal isolate MH7 was later identified as a new strain of Penicillium on the basis of its morphological characteristics and phylogenetic analysis of the 188 rDNA sequence.

• Journal of Microbiology and Biotechnology
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• 제20권2호
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• pp.238-244
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• 2010

Rhizobia are well-known for their ability to infect and nodulate legume roots, forming a nitrogen-fixing symbiosis of agricultural importance. In addition, recent studies have shown that rhizobia can colonize roots and aerial plant tissues of rice as a model plant of the Graminaceae family. Here we show that rhizobia can invade tobacco, a model plant belonging to the Solanaceae family. Inoculation of seedling. roots with five GFP-tagged rhizobial species followed by microscopy and viable plating analyses indicated their colonization of the surface and interior of the whole vegetative plant. Blockage of ascending epiphytic migration by coating the hypocotyls with Vaseline showed that the endophytic rhizobia can exit the leaf interior through stomata and colonize the external phyllosphere habitat. These studies indicate rhizobia can colonize both below- and above-ground tissues of tobacco using a dynamic invasion process that involves both epiphytic and endophytic lifestyles.

• Journal of Microbiology and Biotechnology
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• 제29권11호
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• pp.1777-1789
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• 2019

Drought is more concerned to be a huge problem for agriculture as it affects plant growth and yield. Endophytic bacteria act as plant growth promoting bacteria that have roles for improving plant growth under stress conditions. The properties of four strains of endophytic bacteria were determined under water deficit medium with 20% polyethylene glycol. Bacillus aquimaris strain 3.13 showed high 1-aminocyclopropane-1-carboxylate (ACC) deaminase production; Micrococcus luteus strain 4.43 produced indole acetic acid (IAA). Exopolysaccharide production was high in Bacillus methylotrophicus strain 5.18 while Bacillus sp. strain 5.2 did not show major properties for drought response. Inoculation of endophytic bacteria into plants, strain 3.13 and 4.43 increased height, shoot and root weight, root length, root diameter, root volume, root area and root surface of Jerusalem artichoke grown under water limitation, clearly shown in water supply at 1/3 of available water. These increases were caused by bacteria ACC deaminase and IAA production; moreover, strain 4.43 boosted leaf area and chlorophyll levels, leading to increased photosynthesis under drought at 60 days of planting. The harvest index was high in the treatment with strain 4.43 and 3.13 under 1/3 of available water, promoting tuber numbers and tuber weight. Inulin content was unchanged in the control between well-watered and drought conditions. In comparison, inulin levels were higher in the endophytic bacteria treatment under both conditions, although yields dipped under drought. Thus, the endophytic bacteria promoted in plant growth and yield under drought; they had outstanding function in the enhancement of inulin content under well-watered condition.

• ALGAE
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• 제24권4호
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• pp.249-256
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• 2009

The occurrence of Laminarionema elsbetiae (Ectocarpaceae, Phaeophyceae), as epi-endophyte of Rhodymenia pseudopalmata (Rhodymeniales, Rhodophyta), described from Santa Isabel, Rawson, Argentina. L. elsbetiae grows in the host tissues forming epi-endophytic relationship in the epidermal, cortical and medullar layers. Epiphytic thalli of L. elsbetiae were unbranched filaments emerging from hostis surface. Reproductive structures of L. elsbetiae on the host were absent. On the contrary, free cultured individuals formed different reproductive structures. Macrozoosporangia containing a single large motile zoospore originated from vegetative cells, they were conical to cylindrical in shape, 30-50 ${\mu}m$ in length and 18-20 ${\mu}m$ in wide. Uniseriate plurilocular zoosporangia were cylindrical shape, 40 ${\mu}m$ in length and 10-13 ${\mu}m$ in wide. Sexual fusion was not seen. In mixed cultures of L. elsbetiae with R. pseudopalmata fronds, L. elsbetiae infected the host, grew as in natural host and, formed macrosporangia between host subcortical cells. Gametophytes of L. elsbetiae were filaments with diffuse growth, branched with a branch pattern alternate or opposite. Gametangia were plurilocular, uni or biseriate and lateral. When mature they contained 2 to 6 isogametes. The presence L. elsbetiae on R. pseudopalmata could be defined as an epi-endophytic relationship. The percentage of infection of R. pseudopalmata thalli by L. elsbetiae was 34%.A25% of the infected thalli presented a low, non-symptomatic level infection, whereas a 62% and a 13% of them exhibited respectively moderate and high indexes of infection.

• The Plant Pathology Journal
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• 제28권1호
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• pp.20-31
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• 2012

Endophytic bacterial communities of tidal flat plants antagonistic to oomycete plant pathogens were studied by the isolation of 256 root colonizing endophytic bacteria from surface-disinfected root tissues of six plants ($Rosa$ $rugosa$, $Suaeda$ $maritima$, $Vitex$ $rotundifolia$, $Carex$ $scabrifolia$, $Glehnia$ $littoralis$ and $Elymus$ $mollis$) growing in a tidal flat area of Namhae Island, Korea. To understand the antagonistic potential, an $in$ $vitro$ antagonistic assay was performed to characterize and identify strains that were antagonistic to the oomycete plant pathogens $Phytophthora$ $capsici$ and $Pythium$ $ultimum$ from the total population. Nine percent of the total number of isolated bacteria exhibited in vitro inhibitory activity against target plant pathogenic oomycetes. Taxonomic and phylogenetic placement of the antagonistic bacteria was investigated by analysis of the 16S rRNA gene sequences. The sequence analysis classified the antagonistic strains into four major classes of the domain bacteria ($Firmicutes$, ${\alpha}-Proteobacteria$, ${\gamma}-Proteobacteria$ and $Actinomycetes$) and 10 different genera. Further production of secondary metabolites, hydrolytic enzymes and plant growth promoting traits were determined for the putative new species of antagonistic endophytic bacteria. These new strains could not be identified as known species of ${\alpha}-Proteobacteria$, and so may represent novel bacterial taxa. The unexpected high antagonistic bacterial diversity associated with the tidal flat plants may be indicative of their importance in tidal flat plants as a promising source of novel antimicrobial compounds and biocontrol agents.

• Journal of Microbiology and Biotechnology
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• 제20권12호
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• pp.1744-1749
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• 2010

The role of endophytic fungi in plant growth and development is well documented. However, endophytic fungi with growth promotion capacity have never been isolated from weeds previously. In the current study, we isolated 8 fungal endophytes from the roots of Monochoria vaginalis, a serious weed of rice paddy in Korea. These isolates were screened on Waito-C, in order to identify plant growth promoting metabolites. Two fungal isolates (M5.A & M1.5) significantly promoted the plant height and shoot length of Waito-C during preliminary screening experiments. The culture filtrates (CFs) of M5.A and M1.5 also promoted the shoot length of Echinocloa crusgalli. Gibberellins (GAs) analysis of the CFs of M5.A and M1.5 showed that these endophytic fungi secrete higher quantities of GAs as compared with wild-type G. fujikuroi KCCM12329. The CF of M5.A contained bioactive GAs ($GA_3$, 2.8 ng/ml; $GA_4$, 2.6 ng/ml, and $GA_7$, 6.68 ng/ml) in conjunction with physiologically inactive $GA_9$ (1.61 ng/ml) and $GA_{24}$ (0.18 ng/ml). The CF of M1.5 contained physiologically active GAs ($GA_3$, 1.64 ng/ml; $GA_4$, 1.37 ng/ml and $GA_7$, 6.29 ng/ml) in conjunction with physiologically inactive $GA_9$ (3.44 ng/ml), $GA_{12}$ (0.3 ng/ml), and $GA_{24}$ (0.59 ng/ml). M5.A and M1.5 were identified as new strains of Penicillium sp. and Aspergillus sp., respectively, based on their 18S rDNA sequence homology and phylogenetic analysis.

• Journal of Ginseng Research
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• 제36권2호
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• pp.211-217
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• 2012

Endophytic fungi were isolated from various tissues (root, stem, petiole, leaf, and flower stalk) of 3- and 4-year-old ginseng plants (Panax ginseng Meyer) cultivated in Korea. The isolated endophytic fungi were identified based on the sequence analysis of the internal transcribed spacer (ITS), 1-5.8-ITS 2. A morphological characterization was also conducted using microscopic observations. According to the identification, 127 fungal isolates were assigned to 27 taxa. The genera of Phoma, Alternaria and Colletotrichum were the most frequent isolates, followed by Fusarium, Entrophospora and Xylaria. Although 19 of the 27 taxa were identified at the species level, the remainder were classified at the genus level (6 isolates), phylum level (Ascomycota, 1 isolate), and unknown fungal species (1 isolate). Endophytic fungi of 13 and 19 species were isolated from 3- and 4-year-old ginseng plants, respectively, and Phoma radicina and Fusarium solani were the most frequently isolated species colonizing the tissues of the 3- and 4-year-old ginseng plants, respectively. The colonization frequency (CF%) was dependant on the age and tissue examined: the CFs of the roots and stems in the 3-year-old ginseng were higher than the CF of tissues in the 4-year-old plants. In contrast, higher CFs were observed in the leaves and petioles of 4-year-old plants, and endophytic fungi in the flower stalks were only detected in the 4-year-old plants. In conclusion, we detected diverse endophytic fungi in ginseng plants, which were distributed differently depending on the age and tissue examined.

• 한국균학회지
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• 제41권3호
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• pp.137-141
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• 2013

오서산의 소나무와 일본잎갈나무 두 수종의 침엽에서 내생균의 다양성을 분석하였다. 총 13개체의 숙수식물에서 채집한 침엽을 표면살균하여 분리한 균주들은 형태적인 특징과 rDNA 유전자(ITS 부위) 분석을 수행하였다. 그 결과 총 37개의 균주가 분리되었으며 이들은 17개의 분류군으로 묶을 수 있었다. 그 중 59%는 Leotiomycetes에 속하였으며, 30%는 Sordariomyetes에, 8%는 Dothideomycetes에 속하였으며, 3%는 Agaricomycetes에 속하는 균으로 판명 되었다. 이러한 결과들은 선행연구의 결과들과 매우 유사하였으며 소나무에서보다 일본잎갈나무에서 내생균의 종 다양성이 높게 나타났다. 특히 Lophodermium 속에 속하는 분류군들이 내생균의 다양성에서 주요한 균류로 확인되었으며, 한국에 분포하는 Lophodermium 속 내 종들에 대한 심도 있는 연구가 요구된다.

• 농업과학연구
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• 제48권3호
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• pp.493-503
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• 2021

Tricholoma matsutake (Pinus mushroom, PM) is one of the most valued ectomycorrhizal fungi in Asia because it is an expensive forest product with a unique flavor and taste. Therefore, many studies have tried to successfully cultivate Tricholoma matsutake artificially in Korea and other countries. However, its physiological and ecological characteristics are still unknown. Thus, we need to understand the diversity and clusters of microorganisms related to Tricholoma matsutake and to identify their core microorganisms related to their growth and production. In this study, we obtained an average of 11,661 fragments from three pine mushrooms with metagenome (an assemblage of genes of all microorganisms in the natural world) analysis from a pine forest located in Pohang, Gyeongsang-Bukdo. Of these, the valid reads were on average 5,073 per sample available for analysis, and the average length of a read was 456 bp. There were an average of 33.3 phyla in the metagenome analysis. Firmicutes phylum made up on an average 46% of the phyla and was dominant among the phyla. The next dominant phylum was Proteobacteria at 27% followed by Bacteroidetes at 17%, Actinobacteria at 5% and Verrucomicrobia at 2%. The Proteobacteria phylum consisted of the γ-proteobacteria class at 54% followed by β-proteobacteria at 37%, α-proteobacteria at 6%, δ-proteobacteria at 2% and ζ-proteobacteria at 0%. The metagenome consisted of the Ruminococcaceae family at 17% followed by Pseudomonadaceae at 13%, Burkholderiaceae at 7%, Bacteroidaceae at 7%, Lachnospiraceae at 7% and Clostridiaceae at 6%.

• Mycobiology
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• 제49권4호
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• pp.385-395
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• 2021

Fungal endophytes have been recorded in various plant species with a richness of diversity, and their presence plays an essential role in host plant protection against biotic and abiotic stresses. This study applied the Illumina MiSeq sequencing platform based on the amplification of fungal ribosomal ITS2 region to analyze fungal endophytic communities of two oak species (Quercus mongolica and Q. serrata) with different oak wilt disease susceptibilities in Korea. The results showed a total of 230,768 sequencing reads were obtained and clustered at a 97% similarity threshold into 709 operational taxonomic units (OTUs). The OTUs of Q. serrata were higher than that of Q. mongolica with the number of 617 OTUs and 512 OTUs, respectively. Shannon index also showed that Q. serrata had a significantly higher level of fungal diversity than Q. mongolica. Total of OTUs were assigned into 5 fungal phyla, 17 classes, 60 orders, 133 families, 195 genera, and 280 species. Ascomycota was the dominant phylum with 75.11% relative abundance, followed by Basidiomycota with 5.28%. Leptosillia, Aureobasidium and Acanthostigma were the most abundant genera detected in Q. serrata with the average relative abundance of 2.85, 2.76, and 2.19%, respectively. On the other hand, Peltaster, Cladosporium and Monochaetia were the most common genera detected in Q. mongolica with the average relative abundance of 4.83, 3.03, and 2.87%, respectively. Our results indicated that fungal endophytic communities were significantly different between two oak species and these differences could influence responses of host trees to oak wilt disease caused by Raffaelea quercus-mongolicae.