• Journal of Microbiology
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• v.40 no.1
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• pp.20-25
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• 2002

An extracellular PHB depolymerase was purified from P. simplicissimum LAR13 cultural medium by Sepharose CL-6B chromatography. When the fungus was grown in a basal salt medium with poly(3-hydroxybutyrate) (PHB) as the sole carbon source, PHB depolymerase production reached maximum at its stationary phase. The mycelial growth rate was higher at 37$^{\circ}C$ than at 30$^{\circ}C$ and even higher than at 25$^{\circ}C$, However, the enzyme production was lower at 37$^{\circ}C$ than 30$^{\circ}C$ or 25$^{\circ}C$. The isolated enzyme is composed of a single polypeptide chain with a molecular mass of about 36 kDa as determined by SDS-PAGE. The optimum conditions for the enzyme activity are pH 5.0 and 45$^{\circ}C$. The enzyme was stable for 30 min at a temperature lower than 50$^{\circ}C$, and stable at pH higher than 2.0 but it was unstable at pH 1.0.1 mM Fe$\^$2+/ reduced the enzyme activity by 56% and the enzyme was inhibited almost completely by 4 mM Fe$\^$2+/ . The enzyme was partially inhibited by phenylmethylsulfonyl fluoride and was very sensitive to diazo-DL-norleucine methyl esters dithiothreitol and mercuric ion. However, N-p - tosyl - L - Iysinechloromethyl ketone, p -hydroxymercuricbenzoate and N- acetylimidazole had no influence upon its activity.

• Mycobiology
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• v.42 no.2
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• pp.100-108
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• 2014

Twelve plant species were collected from the east coast of Korea to identify culturable endophytes present in their roots. The fungal internal transcribe spacer (ITS) region (ITS1-5.8SrRNA-ITS2) was used as a DNA barcode for identification of fungi. A total of 194 fungal strains were identified and categorized into 31 genera. The genus Penicillium accounted for the largest number of strains, followed by the genus Aspergillus. Furthermore, using 5 statistical methods, the diversity indices of the fungi were calculated at the genus level. After comprehensive evaluation, the endophytic fungal group from Phragmites australis ranked highest in diversity analyses. Several strains responsible for plant growth and survival (Penicillium citrinum, P. funiculosum, P. janthinellum, P. restrictum, and P. simplicissimum), were also identified. This study provides basic data on the sheds light on the symbiotic relationship between coastal plants and fungi.

• Journal of Microbiology and Biotechnology
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• v.24 no.9
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• pp.1149-1161
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• 2014

Cotton plants were sampled and ranked according to their resistance to Verticillium wilt. In total, 642 endophytic fungi isolates representing 27 genera were recovered from Gossypium hirsutum root, stem, and leaf tissues, but were not uniformly distributed. More endophytic fungi appeared in the leaf (391) compared with the root (140) and stem (111) sections. However, no significant difference in the abundance of isolated endophytes was found among resistant cotton varieties. Alternaria exhibited the highest colonization frequency (7.9%), followed by Acremonium (6.6%) and Penicillium (4.8%). Unlike tolerant varieties, resistant and susceptible ones had similar endophytic fungal population compositions. In three Verticillium-wilt-resistant cotton varieties, fungal endophytes from the genus Alternaria were most frequently isolated, followed by Gibberella and Penicillium. The maximum concentration of dominant endophytic fungi was observed in leaf tissues (0.1797). The evenness of stem tissue endophytic communities (0.702) was comparatively more uniform than the other two tissues. Eighty endophytic fungi selected from 27 genera were evaluated for their inhibition activity against highly virulent Verticillium dahliae isolate Vd080 in vitro. Thirty-nine isolates exhibited fungistasis against the pathogen at varying degrees. Seven species, having high growth inhibition rates (${\geq}75%$), exhibited strong antifungal activity against V. dahliae. The antifungal activity of both volatile and nonvolatile metabolites was also investigated. The nonvolatile substances produced by CEF-818 (Penicillium simplicissimum), CEF-325 (Fusarium solani), CEF-714 (Leptosphaeria sp.), and CEF-642 (Talaromyces flavus) completely inhibited V. dahliae growth. These findings deepen our understanding of cotton-endophyte interactions and provide a platform for screening G. hirsutum endophytes with biocontrol potential.