Control Efficacy of Streptomyces sp. A501 against Ginseng Damping-off and Its Antifungal Substance.

Ginseng damping-off, caused by the fungal pathogens Rhizoctonia solani and Pythium sp., is a critical disease in ginseng seedling. In a continuing effort to find microorganisms with the potential of acting as a biocontrol agent against Rhizoctonia damping-off, we found that a Streptomyces sp. A501 showed significant antifungal activity against Rhizoctonia solani. In field experiment to test the efficacy of Streptomyces sp. A501 in controlling ginseng damping-off, the incidence of damping-off disease was meaningfully reduced when ginseng seeds were soaked in the culture broth of Streptomyces sp. A501 before sowing. To perform characterization of the antifungal compound, we isolated it from the culture broth of strain A501 through Diaion HP-20 and silica gel column chromatographies and preparative high-performance liquid chromatography. The structure of the antifungal compound was assigned as fungichromin by spectroscopic methods, mainly nuclear magnetic resonance and electrospray ionization-mass analysis.

Ginsenoside Rg1 and 20(S)-Rg3 Induce IgA Production by Mouse B Cells.

Ginsenosides are the major components of ginseng, which is known to modulate blood pressure, metabolism, and immune function, and has been used to treat various diseases. It has been reported that ginseng and several ginsenosides have immunoregulatory effects on the innate and T cell-mediated immune response. However, their effects on the humoral immune response have not been fully explored. The present study examined the direct effects of red ginseng extract (RGE) and ginsenosides on mouse B cell proliferation and on antibody production and the expression of germline transcripts (GLT) by mouse B cells in vitro. RGE slightly reduced B cell proliferation, but increased IgA production by LPS-stimulated B cells. Furthermore, ginsenoside Rg1 and 20(S)-Rg3 selectively induced IgA production and expression of GLTα transcripts by LPS-stimulated B cells. Collectively, these results suggest that ginsenoside Rg1 and 20(S)-Rg3 can drive the differentiation of B cells into IgA-producing cells through the selective induction of GLTα expression.

Protective effect of ginsenoside-Rb2 from Korean red ginseng on the lethal infection of haemagglutinating virus of Japan in mice.

Korean red ginseng has been shown to possess a variety of biological activities. However, little is known about antiviral activity of ginsenosides of Korean red ginseng. Here, we investigated the protective effect by oral administration of various ginsenosides on the lethal infection of haemagglutinating virus of Japan (HVJ) in mice. In a lethal infection model in which almost all mice infected with HVJ died within 15 days, the mice were administered orally (per os) with 1 mg/mouse of dammarane-type (ginsenoside-Rb1, -Rb2, -Rd, -Re, and -Rg2) or oleanolic acid-type (ginsenoside-Ro) ginsenosides 3, 2, and 1 d before virus infection. Ginsenoside-Rb2 showed the highest protective activity, although other dammarane-type and oleanolic acid-type ginsenosides also induced a significant protection against HVJ. However, neither the consecutive administration with a lower dosage (300 µg/mouse) nor the single administration of ginsenoside-Rb2 (1 mg/mouse) was active. In comparison of the protective activity between ginsenoside-Rb2 and its two hydrolytic products [20(S)- and 20(R)-ginsenoside-Rg3], 20(S)-ginsenoside-Rg3, but not 20(R)-ginsenoside-Rg3, elicited a partial protection against HVJ. The protective effect of ginsenoside-Rb2 and 20(S)-ginsenoside-Rg3 on HVJ infection was confirmed by the reduction of virus titers in the lungs of HVJ-infected mice. These results suggest that ginsenoside-Rb2 is the most effective among ginsenosides from red ginseng to prevent the lethal infection of HVJ, so that this ginsenoside is a promising candidate as a mucosal immunoadjuvant to enhance antiviral activity.

How do weather extremes affect rice productivity in a changing climate? An answer to episodic lack of sunshine.

Here, we experimentally examined how an episodic lack of sunshine (ELS), as an extreme weather event, would affect rice productivity under warming with elevated [CO2 ]. In 2009 and 2010, rice plants were grown at two levels of [CO2 ] (ca. 390 and 650 µl l(-1) ) and three levels of warming (≈ambient, +1.2 °C, and +2.2/2.4 °C) in six independent temperature gradient field chambers (three each for ambient and elevated [CO2 ]). At panicle initiation (PI), booting (BT), or flowering (FL), rice plants were exposed to ELS (ca. 18% of full sunlight) for 10-14 days consecutively. As expected, ELS elicited a significant reduction in aboveground biomass (AGB) and yields. However, elevated [CO2 ] had the potential to relieve the ELS-induced reduction in AGB and yield, whereas warming had the reverse effect for yields, without a significant warming × [CO2 ] interaction. When ELS applied at PI, BT, and FL, the extents to which warming-reduced yields (averaged across [CO2 ] levels) ranged from 9 to 25%, 7 to 14, and 10 to 18% at +1.2 °C, and ranged from 24 to 56%, 22 to 55%, and 18 to 46% at +2.2/2.4 °C across two seasons, respectively. Meanwhile, under normal sunshine they ranged from 1 to 3% at +1.2 °C and 7 to 21% at +2.2/2.4 °C. Warming predisposed rice plants that had experienced ELS to be more sensitive to spikelet sterility and spikelet number per panicle, accounting for most of the yield reductions. These findings provide evidence that an expected warming could further exacerbate rice productivity if ELS occurs simultaneously during reproductive stages. Our results collectively suggest that it might be critically important to consider extreme events for a holistic evaluation of the potential impact of warming and [CO2 ] on crop productivity, when considering changing climate.

Increase in Insulin Secretion Induced by Panax ginseng Berry Extracts Contributes to the Amelioration of Hyperglycemia in Streptozotocininduced Diabetic Mice.

Panax ginseng has long been used as a traditional herbal medicine. More recently, it has received attention for its anti-diabetic and anti-obesity effects in humans and in animal models of type 2 diabetes. In the present study, we tested the hypoglycemic effects of ginseng berry extract in beta-cell-deficient mice and investigated the mechanisms involved. Red (ripe) and green (unripe) berry extracts were prepared and administered orally (100 or 200 mg/kg body weight) to streptozotocin-induced diabetic mice daily for 10 wk. The body weight was measured daily, and the nonfasting blood glucose levels were measured after 5 and 10 wk after administration. Glucose tolerance tests were performed, and the serum insulin levels were measured. The proliferation of betacells was measured in vitro. The administration of red or green ginseng berry extract significantly reduced the blood glucose levels and improved the glucose tolerance in beta-cell deficient mice, with the higher doses resulting in better effects. Glucose-stimulated insulin secretion was significantly increased in berry extract-treated mice compared with streptozotocin-induced diabetic control mice. Treatment with ginseng berry extract increased beta-cell proliferation in vitro. Both red berry and green berry extracts improved glycemic control in streptozotocin-induced diabetic mice and increased insulin secretion, possibly due to increased beta-cell proliferation. These results suggest that ginseng berry extracts might have beneficial effects on beta-cell regeneration.

Enzymes hydrolyzing structural components and ferrous ion cause rusty-root symptom on ginseng (Panax ginseng).

Microbial induction of rusty-root was proved in this study. The enzymes hydrolyzing plant structural materials, including pectinase, pectolyase, ligninase, and cellulase, caused the rusty-root in ginseng. Pectinase and pectolyase produced the highest rusty-color formation. Ferrous ion (Fe+++) caused the synergistic effect on rusty-root formation in ginseng when it was used with pectinase. The effect of ferric ion (Fe++) on rusty-root formation was slow, compared with Fe+++, probably due to gradual oxidation to Fe+++. Other metal ions including the ferric ion (Fe++) did not affect rusty-root formation. The endophytic bacteria Agrobacterium tumefaciens, Lysobacter gummosus, Pseudomonas veronii, Pseudomonas marginalis, Rhodococcus erythropolis, and Rhodococcus globerulus, and the rotten-root forming phytophathogenic fungus Cylindrocarpon destructans, caused rusty-root. The polyphenol formation (rusty color) was not significantly different between microorganisms. The rotten-root-forming C. destructans produced large quantities of external cellulase activity (about 2.3 U[micronM/min/mg protein]), which indicated the pathogenecity of the fungus, whereas the bacteria produced 0.1-0.7 U. The fungal external pectinase activities (0.05 U) and rusty-root formation activity were similar to those of the bacteria. In this report, we proved that microbial hydrolyzing enzymes caused rusty-root (Hue value 15 degrees) of ginseng, and ferrous ion worsened the symptom.

Application of genetic marker and real-time polymerase chain reaction for discrimination between Forsythia viridissima and Forsythia suspensa.

Forsythiae Fructus has been used as a herbal medicine for a fruit of Forsythia viridissima LINDLEY or Forsythia suspensa VAHL (Oleaceae). In Korea, the fruit of Forsythia viridissima is used and in China, the fruit of Forsythia suspensa is used generally. There are differences in the amount and distribution of constituents between Forsythia viridissima (FV) and Forsythia suspensa (FS). Accordingly, a discrimination of these two herbal drugs is needed. In this study, we designed FV genetic marker based on the internal transcribed spacer (ITS) sequence of nuclear ribosomal DNA that can discriminate Forsythia viridissima and Forsythia suspensa and species-specific amplification product 252 bp was confirmed. Using the real-time polymerase chain reaction (PCR) (allelic discrimination) analysis, an accurate discrimination between Forsythia viridissima and Forsythia suspensa was accomplished. Accordingly, with the use of PCR analysis based on ITS region sequence of ribosomal DNA and the real-time PCR analysis which can efficiently discriminate between Forsythia viridissima and Forsythia suspensa was developed.

Ginsenoside content of berries and roots of three typical Korean ginseng (Panax ginseng) cultivars.

The ginsenoside content of berries and roots of three cultivars of Korean ginseng have been investigated. For all cultivars, ginsenoside Re was the most abundant ginsenoside in roots and berries. However, berries produced more total ginsenosides, and berry the ginsenoside profile differed from that of roots. The ginsenoside Re content of berries was 4-6 times more than that of roots. Averaged across all cultivars, the amounts of the five ginsenosides in berries was Re > Rc approximately = Rg1 approximately = Rb1 approximately = Rd. For roots, the amounts were Re > Rg1 > Rb1 > Rc > Rd. Roots of the Yunpoong cultivar had the greatest ginsenoside content, followed by roots of the Chunpoong cultivar and the Gumpoong cultivar. The total amount of ginsenosides (especially Rb1, Re, and Rg1) was greatest in the Yunpoong cultivar.

Enhancement of tolerance to soft rot disease in the transgenic Chinese cabbage (Brassica rapa L. ssp. pekinensis) inbred line, Kenshin.

We developed a transgenic Chinese cabbage (Brassica rapa L. ssp. pekinensis) inbred line, Kenshin, with high tolerance to soft rot disease. Tolerance was conferred by expression of N-acyl-homoserine lactonase (AHL-lactonase) in Chinese cabbage through an efficient Agrobacterium-mediated transformation method. To synthesize and express the AHL-lactonase in Chinese cabbage, the plant was transformed with the aii gene (AHL-lactonase gene from Bacillus sp. GH02) fused to the PinII signal peptide (protease inhibitor II from potato). Five transgenic lines were selected by growth on hygromycin-containing medium (3.7% transformation efficiency). Southern blot analysis showed that the transgene was stably integrated into the genome. Among these five transgenic lines, single copy number integrations were observed in four lines and a double copy number integration was observed in one transgenic line. Northern blot analysis confirmed that pinIISP-aii fusion gene was expressed in all the transgenic lines. Soft rot disease tolerance was evaluated at tissue and seedling stage. Transgenic plants showed a significantly enhanced tolerance (2-3-fold) to soft rot disease compared to wild-type plants. Thus, expression of the fusion gene pinIISP-aii reduces susceptibility to soft rot disease in Chinese cabbage. We conclude that the recombinant AHL-lactonase, encoded by aii, can effectively quench bacterial quorum-sensing and prevent bacterial population density-dependent infections. To the best of our knowledge, the present study is the first to demonstrate the transformation of Chinese cabbage inbred line Kenshin, and the first to describe the effect of the fusion gene pinIISP-aii on enhancement of soft rot disease tolerance.

Growth and rutin production in hairy root cultures of buckwheat (Fagopyrum esculentum M.).

Buckwheat (Fagopyrum esculentum Moench.) is a potentially important source of rutin, a natural flavonoid with antihyperglycemic, antihypertensive, and antioxidative properties. To examine in vitro production of rutin, we established a hairy root culture of buckwheat by infecting leaf explants with Agrobacterium rhizogenes R1000, and tested the growth conditions and rutin production rates of these cultures. Ten hairy root clones were established; their growth and rutin production rates ranged from 233 to 312 (mg dry wt per 30 mL flask, and 0.8 to 1.2 (mg/g dry wt), respectively. Clone H8, which had high growth and rutin production rates (312 mg dry wt per 30 mL flask and 1.2 mg/g dry wt, respectively), was selected for further experiments. H8 showed maximal growth and rutin content at 30 days in culture in MS medium. Of four tested culture media, half-strength MS medium was found to induce the highest levels of growth (378 mg dry wt per 30 mL flask) and rutin production (1.4 mg/g dry wt) by clone H8. In contrast, supplementation with auxins (0.1-1 mg/l IAA, IBA and NAA) increased the growth rate, but had no significant effect on rutin production by H8. Collectively, these findings indicate that hairy root cultures of buckwheat culture could be a valuable alternative approach for rutin production.

Pseudomonas panacis sp. nov., isolated from the surface of rusty roots of Korean ginseng.

A Gram-negative, aerobic bacterium, designated CG20106(T), was isolated from the surface tissues of rusty root lesions of Korean ginseng. Phylogenetic analysis of the 16S rRNA gene sequence revealed that this isolate represents a hitherto unknown subline within the genus Pseudomonas. Strain CG20106(T) was catalase- and oxidase-positive, motile and rod-shaped. The overall phenotypic features of the ginseng isolate were similar to those of Pseudomonas cedrina, Pseudomonas migulae and Pseudomonas azotoformans. However, several physiological and chemotaxonomic properties can be weighted to distinguish the isolate from these organisms. The major fatty acids were C(16:1)omega7c and/or iso-C(15:0) 2-OH (summed feature 3, 36.4+/-0.4%), C(16:0) (27.5+/-0.7%) and C(18:1)omega7c (19.4+/-0.2%). The DNA G+C content was 61.4 mol%. On the basis of the polyphasic results revealed in this study, the name Pseudomonas panacis sp. nov. is proposed for strain CG20106(T). The type strain is CG20106(T) (=IMSNU 14100(T)=CIP 108524(T)=KCTC 12330(T)).

Janibacter melonis sp. nov., isolated from abnormally spoiled oriental melon in Korea.

Two Gram-positive bacterial strains, CM2104(T) and CM2110, isolated from the inner part of abnormally spoiled oriental melon (Cucumis melo) in Korea, were subjected to a polyphasic taxonomic study. The cell-wall peptidoglycan of strains CM2104(T) and CM2110 contained meso-diaminopimelic acid as the diagnostic diamino acid. The predominant menaquinone was MK-8(H(4)). The major fatty acids detected in the two strains were iso-C(16 : 0), C(17 : 1)omega8c and C(18 : 1)omega9c or C(17 : 0). The DNA G+C content of the two strains was 73 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that the strains formed a coherent cluster with a clade comprising two Janibacter species, Janibacter limosus and Janibacter terrae. Strains CM2104(T) and CM2110 exhibited a 16S rRNA gene sequence similarity value of 99.7 % and a mean DNA-DNA relatedness level of 89 %. Strains CM2104(T) and CM2110 showed 16S rRNA gene sequence similarity levels of 97.8-98.4 % to the type strains of J. limosus and J. terrae. DNA-DNA relatedness between strains CM2104(T) and CM2110 and the type strains of these two Janibacter species was 7-11 %. On the basis of the phenotypic and phylogenetic data and genomic distinctiveness, strains CM2104(T) and CM2110 should be placed within the genus Janibacter as members of a novel species, for which the name Janibacter melonis sp. nov. is proposed. The type strain is CM2104(T) (=KCTC 9987(T)=DSM 16063(T)=JCM 12321(T)).

Identification of rice genes induced in a rice blast-resistant mutant.

To clarify mechanisms of rice blast resistance in rice plants we used suppression subtractive hybridization (SSH) to isolate genes induced upon rice blast inoculation in a rice blast-resistant mutant. A total of 26 rice cDNAs were isolated and found to have elevated expression upon rice blast infection in a rice blast-resistant derivative, SHM-11, of the rice cultivar, Sanghaehyanghyella. Sequencing of the cDNAs revealed that many of the proteins they encoded had been previously described as involved in plant responses against pathogen attack. Two interesting groups of the defense-related proteins consisted of three different PR5 homologues and four different protease inhibitors, all highly expressed in the rice blast mutant. Genes encoding proteins involved in signal transduction and regulation were also identified, including translation initiation factor eIF5A, C2 domain DNA binding protein, putative rice EDS and putative receptor like kinase. Most of the identified cDNAs were highly expressed 24 h after blast inoculation. Our results suggest that a pathway regulating defense gene expression may be altered in the mutant, resulting in early induction of the defense genes upon fungal infection.