Efficient production of polysaccharide by Chaetomium globosum CGMCC 6882 through co-culture with host plant Gynostemma pentaphyllum.

Endophytic fungus, as a new kind of microbial resources and separated from plants, has attracted increasing attention due to its ability to synthesize the same or similar bioactive secondary metabolites as the host plants. Nevertheless, the effects of the symbiotic relationship between microorganisms and elicitors existed in host plant on metabolite production are not adequately understood. In the present work, the impacts of elicitors (ginseng saponin and puerarin) and symbiotic microorganisms on endophytic fungus Chaetomium globosum CGMCC 6882 synthesizing polysaccharide were evaluated. Results show that the polysaccharide titers increased from 2.36 to 3.88 g/L and 3.67 g/L with the addition of 16 µg/L ginseng saponin and puerarin, respectively. Moreover, the maximum polysaccharide titer reached 4.55 g/L when C. globosum CGMCC 6882 was co-cultured with UV-irradiated G. pentaphyllum. This work brings a significant contribution to the research and interpretation of the relationship between endophytic fungus and its host plant.

[Diversity of Endogeny Eumycetes in Gynostemma pentaphyllum and Its Correlation with Gypenoside XLIX].

OBJECTIVE: To study the correlation between active components and endogeny eumycetes in Gynostemma pentaphyllum of different types from different habitats. METHODS: Endogeny eumycetes from different parts of Gynostemma pentaphyllum were isolated by general isolation methods. Insert method and point planting method were used for identification. The content of gypenoside XLIX were determined by HPLC. RESULTS: 125 endogeny eumycetes inhabiting in Gynostemma pentaphyllum were isolated from roots, rhizomes and leaves. By colony morphology and microscopic characteristics, 22 genera from 10 families, 7 orders, 2 classes were identified. Fusarium was the most abundant endogeny eumycetes in Gynostemma pentaphyllum with the account of 22. 4%. Penicillium and Leptosphaeria was 12. 8% and 9. 6% respectively. The correlation between Gypenoside XLIX and endogeny eumycetes in Gynostemma pentaphyllum was revealed. CONCLUSION: Endogeny eumycetes are diverse in species and quantity. The endogeny eumycetes species is related to the quality of Gynostemma pentaphyllum.

Arthrobacter gyeryongensis sp. nov., isolated from soil of a Gynostemma pentaphyllum field.

A Gram-stain-positive, flagellate, rod-shaped, catalase- and oxidase-positive bacterium, designated DCY72(T), was isolated from the soil of a Gynostemma pentaphyllum field. Growth occurred at 4-34 °C (optimum 30 °C), at pH 4-10 (optimum pH 7), and with 0-5% NaCl (w/v). The major menaquinones of strain DCY72(T) were MK-9(H2) (81.0 %) and MK-10(H2) (12.2%). The major amino acid present in the cell-wall peptidoglycan was L-lysine. The major fatty acids were anteiso-C(15 : 0) and anteiso-C(17 : 0). The genomic DNA G+C content was 64.5 mol%. 16S rRNA gene sequence analysis revealed that strain DCY72(T) belonged to the family Micrococcaceae and was most closely related to Arthrobacter ramosus CCM 1646(T) (98.2% similarity). The DNA-DNA relatedness between strain DCY72(T) and A. ramosus KACC 14391(T) (98.2% 16S rRNA gene sequence similarity), Arthrobacter nitroguajacolicus KACC 14581(T) (97.6%), Arthrobacter nicotinovorans KACC 20508(T) (97.3%) and Arthrobacter aurescens KACC 20528(T) (97.3%). was 12.9% ± 0.3, 25.6% ± 0.3, 26.6% ± 0.5 and 23.2% ± 0.9, respectively. On the basis of the phenotypic characteristics, genotypic analysis and physiological characteristics, strain DCY72(T) represents a novel species of the genus Arthrobacter, for which the name Arthrobacter gyeryongensis sp. nov. is proposed. The type strain is DCY72(T) ( = KCTC 33072(T) = JCM 18514(T)).

[Molecular diversity of arbuscular mycorrhizal fungi in wild and cultured Gynostemma pentaphyllum roots in Xishuangbanna, Southwest China].

By using nested-PCR, DNA cloning, and sequencing techniques, this paper studied the diversity of the community structure of arbuscular mycorrhizal fungi (AMF) in wild and cultured Gynostemma pentaphyllum roots. A total of 551 clones containing 18S rDNA genes of AMF were obtained from the roots. After the analysis of the restriction fragment length polymorphism, 100 different RFLP types were obtained, which were further divided into 20 AMF phylotypes belonging to seven families. The comparison of the sequences of 20 AMF phylotypes with the GenBank database showed that there were 5 AMF phylotypes having high similarity to the sequences of reported AMF species Glomus viscosum, Claroideoglomus etunicatum, Racocetra tropicana, Acaulospora spinosa, and Acaulospora mellea, respectively. These sequences were then assessed for the similarities against the MaarjAM database, and 12 phylotypes showed high similarity to the corresponding molecular virtual taxa, of which, 7 phylotypes were not obtained by the morphological identification of soil asexual spores. Statistical analysis indicated that there were significant differences in the AMF community between wild and cultured G. pentaphyllum roots. The analysis of relative abundance data indicated that Glo-2, Amb-1, and Para-1 were the dominant phylotypes in wild G. pentaphyllum roots, while Glo-3, Glo-8, Glo-10, and Div-1 were the prevalent phylotypes in cultured ones. Claroideoglomeraceae and Ambisporaceae were only detected in wild G. pentaphyllum roots, and Diversisporaceae was only identified in cultured ones.

[Effects of different factors on transformed hairy root in Gynostemm apentaphyllum].

OBJECTIVE: To induce hairy roots of Gynostemm apentaphyllum by Agrobacterium rhizogenes strains. METHODS: Hairy roots were induced by the co-culture method of explants and Agrobacterium rhizogenes strains. Effects of different Agrobacterium rhizogenes strains, explants, pre(co)-culture time, Bacterial concentration, infecting time, As concentration and antibiotic medium on the transformation frequency were studied. RESULTS: The highest induction frequency was obtained form leaf 2 days co-cultivation, which were induced by Agrobacterium rhizogenes OD 600 0. 8 for 10 min, 100 micromol/L As and MS + 300 mg/L Cab. CONCLUSION: Hairy roots were induced by co-cultivation and the optimum induced condition were determined.